diff --git a/CLAUDE.md b/CLAUDE.md
index 5ff74582..2f20d219 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -145,6 +145,9 @@ Swarm-level:
   crates.
 - **`swarm-builder/`** — builds agent config PR heads for commit status.
   Design: [`docs/swarm/builder.md`](docs/swarm/builder.md).
+- **`swarm-claude-login/`** — runs `claude auth login` for one agent and
+  stores the credentials at `swarm/agents/<agent>/claude-credentials`.
+  Design: [`docs/swarm/claude-login.md`](docs/swarm/claude-login.md).
 - **`swarm-review-classifier/`** — one `claude --print` per PR
   classification, no tools, no forge credential. Design:
   [`docs/swarm/review-classifier.md`](docs/swarm/review-classifier.md).
diff --git a/Cargo.lock b/Cargo.lock
index c735e9e0..2308ca36 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4851,6 +4851,21 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "swarm-claude-login"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "async-nats",
+ "futures-util",
+ "hive-log",
+ "serde_json",
+ "swarm-queue-client",
+ "swarm-secret-client",
+ "tokio",
+ "tracing",
+]
+
 [[package]]
 name = "swarm-controller"
 version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
index 096d4bd8..8f9f1a9b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,6 +28,7 @@ members = [
   "swarm-agent-verify",
   "swarm-authelia-bridge",
   "swarm-builder",
+  "swarm-claude-login",
   "swarm-authelia-bridge-sock",
   "swarm-controller",
   "swarm-matrix-client",
diff --git a/docs/README.md b/docs/README.md
index 0121a33e..95c804ef 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -91,6 +91,9 @@ declarations.
   (planned, not implemented yet).
 - **Does an agent config PR build before it's merged?** →
   [`swarm/builder.md`](swarm/builder.md).
+- **How do I log an agent in to claude from the swarm UI, and why doesn't a
+  stale stored copy log it out again?** →
+  [`swarm/claude-login.md`](swarm/claude-login.md).
 
 ## Scheduler, CI, observability
 
diff --git a/docs/swarm/claude-login.md b/docs/swarm/claude-login.md
new file mode 100644
index 00000000..10fa3d42
--- /dev/null
+++ b/docs/swarm/claude-login.md
@@ -0,0 +1,66 @@
+# Claude login from the swarm UI
+
+An operator logs an agent in to claude from the agent's card in the swarm UI.
+No hive is in the path: the login runs in the swarm's `swarm-claude-login`
+service, the credentials go to the agent's own leaf in the secret store, and the
+agent's harness installs them from there.
+
+Where it runs and how it's enabled: [`services.md`](services.md#claude-login-minter).
+
+## What happens on a login
+
+1. The agent publishes `needs_login` in its turn-state header, and its card
+   shows **login needed** with a **log in** button.
+2. **log in** opens a dialog, which calls
+   `POST /api/agents/<agent>/claude-login`. swarm-controller relays the start as
+   a request on the queue subject `$SWARM.claude-login.request`.
+3. The minter runs `claude auth login` with `HOME` and `CLAUDE_CONFIG_DIR` in a
+   fresh scratch directory, over plain stdio pipes, and answers with the first
+   `https://` URL it prints. The dialog shows that URL.
+4. The operator opens the URL, signs in to the agent's own claude account, and
+   pastes the code the page shows into the dialog, which posts it to
+   `POST /api/agents/<agent>/claude-login/code`.
+5. The minter writes the code to claude's stdin and waits for it to exit. It
+   stores the `.credentials.json` claude wrote at
+   `swarm/agents/<agent>/claude-credentials` (field `value`), as a new version
+   over any stored before, and removes the scratch directory.
+6. The agent's harness, while it waits for a login, reads that leaf every 30
+   seconds under the agent's own certificate. When the stored version is newer
+   than the one it installed last, it writes the file to
+   `~/.claude/.credentials.json`, records the version, and resumes its turn
+   loop as it does after a login from the agent's web UI.
+
+A started login waits 15 minutes for its code, then the minter stops it.
+Starting another login for the same agent replaces the running one. Each step
+has a minute to finish; a refused code fails the login, and the dialog shows
+what claude printed.
+
+## Why the harness takes only a newer version
+
+`claude` rotates the refresh token in `.credentials.json` as it uses the
+session, and the agent can't write the store. After the first refresh the
+stored copy is stale. A harness that installed it whenever the bytes differed
+would replace the agent's live session with a stale copy and log the agent
+out. The harness therefore compares the store's KV version with the last
+version it installed (`claude-credentials-version` under the harness dir):
+
+- it installs a newer version, that is, a new login;
+- it leaves an equal or older version alone, even when the agent needs a
+  login again, so it never puts back a session that has gone bad;
+- it reads nothing while the agent has a session.
+
+## Credentials
+
+| Principal                              | Grant                                                                                                                |
+| -------------------------------------- | -------------------------------------------------------------------------------------------------------------------- |
+| `swarm-claude-login`, in its container | `create`, `update` on `swarm/agents/+/claude-credentials`; `read` on `swarm/services/<minter client id>/oidc/client` |
+| the agent, under its own certificate   | `read` on its own `swarm/agents/<agent>/*`, which covers the leaf                                                    |
+
+The minter has no read on the leaf and nothing else under an agent. Every
+hive's policy reads `swarm/agents/*`, so every hive can read every agent's
+claude session, as it can read the GitHub token.
+
+## What stays
+
+The agent's own web UI login (`/login`) still works, unchanged. It goes away
+once the operator has confirmed the swarm login works.
diff --git a/docs/swarm/credentials.md b/docs/swarm/credentials.md
index 7fd613a3..2c5cd4e4 100644
--- a/docs/swarm/credentials.md
+++ b/docs/swarm/credentials.md
@@ -68,6 +68,7 @@ of the cell says how.
 | `swarm/agents/<agent>/forge-token`                          | `swarm-controller`, at agent creation and in a pass every 5 minutes over every agent with a store identity                                                                                                  | the agent container itself, under its own certificate, fetched to `/run/hive-agent-forge-token/token`                                                                                                                                                                                                                                                                                                               | ✅ the controller re-mints when the stored token is missing or no longer matches the forge (last eight characters and scopes)                                                                                                                                                                                                                                        | ✅ the agent re-fetches on a 10-minute timer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
 | `swarm/agents/<agent>/forge/<label>`                        | `swarm-controller`, when an operator links an external forge account in the swarm UI                                                                                                                        | `hive-agent-forge-accounts` in the agent container, under the agent's own certificate, into `<state>/forge-<label>-token` and `forge-<label>.json`                                                                                                                                                                                                                                                                  | ❌ an operator's token; replaced only by deleting it and linking the label again                                                                                                                                                                                                                                                                                     | ✅ the agent re-fetches on a 2-minute timer                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
 | `swarm/agents/<agent>/github-token`                         | `swarm-controller`, when an operator links a GitHub account in the swarm UI                                                                                                                                 | `hive-agent-github-token` in the agent container, under the agent's own certificate, into `<state>/github-token`                                                                                                                                                                                                                                                                                                    | ❌ an operator's token; replaced only by deleting it and linking it again                                                                                                                                                                                                                                                                                            | ✅ the agent re-fetches on a 2-minute timer, and `hive-github-notify` re-reads the file on every poll                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+| `swarm/agents/<agent>/claude-credentials`                   | `swarm-claude-login`, under its own certificate, when an operator logs the agent in from its card in the swarm UI; a new version per login                                                                  | `hive-agent` in the agent container, under the agent's own certificate, into `~/.claude/.credentials.json`, only while the agent waits for a login and only a version newer than the one it installed last                                                                                                                                                                                                          | ❌ an operator's login; a relogin writes a new version                                                                                                                                                                                                                                                                                                               | ✅ the waiting agent reads the store every 30 seconds                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
 | `swarm/hives/<hive>/matrix/sender-token`                    | `swarm-controller`, with the swarm's appservice token, for every hive in its directory in a five-minute pass                                                                                                | `swarm-controller` under its own certificate, before it decides whether to mint, and hive-c0re's `stored_sender_token()`, under the hive's own certificate                                                                                                                                                                                                                                                          | ✅ the controller's pass re-mints when the stored token is missing, unknown to the homeserver, or someone else's                                                                                                                                                                                                                                                     | ✅ hive-c0re's matrix sweep reads the store every run and overwrites its token file when the store's token differs                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
 | `swarm/hives/<hive>/forge/token`                            | `swarm-controller`, with the forge's admin API, for every hive in its directory in a five-minute pass                                                                                                       | `swarm-controller` under its own certificate, before it decides whether to mint, and hive-c0re's `forge::reader_token()`, under the hive's own certificate                                                                                                                                                                                                                                                          | ✅ the controller's pass re-mints when the stored token is missing or no longer matches the forge (last eight characters and scopes)                                                                                                                                                                                                                                 | ✅ hive-c0re reads the store on every forge read                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
 | `swarm/hives/<hive>/queue/agent`                            | authelia                                                                                                                                                                                                    | `swarm-bao-queue-agent` on the hive's host, under its own per-hive certificate; no agent's policy reaches it                                                                                                                                                                                                                                                                                                        | must be stated                                                                                                                                                                                                                                                                                                                                                       | must be stated                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
diff --git a/docs/swarm/secrets.md b/docs/swarm/secrets.md
index 0c590ac2..1acbdf35 100644
--- a/docs/swarm/secrets.md
+++ b/docs/swarm/secrets.md
@@ -405,10 +405,10 @@ next controller restart.
 ### Per-principal identities
 
 Bao matches a cert-auth role on the certificate's subject, so a certificate is an
-identity and sharing one merges the identities. Each of these eight leaves has
+identity and sharing one merges the identities. Each of these nine leaves has
 a role and a policy of its own, and reaches one path, except the review
-classifier's, the builder's, the forge host's and Grafana's, which reach two
-each:
+classifier's, the builder's, the claude login minter's, the forge host's and
+Grafana's, which reach two each:
 
 | unit                                                | option pair under `deploy.bao.`                                    | reads, or writes                                                                                                                                              |
 | --------------------------------------------------- | ------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
@@ -418,28 +418,30 @@ each:
 | `swarm-bao-forwarder-oidc`                          | `forwarderOidcClientCertFile` / `forwarderOidcClientKeyFile`       | `swarm/services/<store forwarder client id>/oidc/client`                                                                                                      |
 | `swarm-bao-ci-runner`                               | `ciRunnerClientCertFile` / `ciRunnerClientKeyFile`                 | `swarm/services/ci-runner/registration-token`                                                                                                                 |
 | `swarm-review-classifier`, in its container         | `reviewClassifierClientCertFile` / `reviewClassifierClientKeyFile` | `swarm/services/review-classifier/anthropic-api-key`, `swarm/services/review-classifier/acp-provider` and `swarm/services/<classifier client id>/oidc/client` |
+| `swarm-claude-login`, in its container              | `claudeLoginClientCertFile` / `claudeLoginClientKeyFile`           | creates and updates `swarm/agents/+/claude-credentials`; reads `swarm/services/<minter client id>/oidc/client`                                                |
 | `swarm-bao-forge-publisher`, `swarm-bao-forge-oidc` | `forgePublisherClientCertFile` / `forgePublisherClientKeyFile`     | writes `swarm/controller/swarm-controller/forge/token`; reads `swarm/services/<forge client id>/oidc/client`                                                  |
 
 The first exists **per hive**, because the path it reads carries a hive name
 and every hive runs its own reader. Its subject is
 `<deploy.bao.queueAgentCommonNamePrefix>-<hive>`; `swarm.nix` reserves that
 composed spelling as a hive name, so nobody can name a hive into another hive's
-role. The other seven reach a path that names a swarm service rather than a hive,
+role. The other eight reach a path that names a swarm service rather than a hive,
 so one role each is enough and their subjects are the flat
 `deploy.bao.grafanaOidcCommonName`, `deploy.bao.otelOidcCommonName`,
 `deploy.bao.forwarderOidcCommonName`, `deploy.bao.ciRunnerCommonName`,
-`deploy.bao.reviewClassifierCommonName`, `deploy.bao.builderCommonName` and
-`deploy.bao.forgePublisherCommonName`. The last is the only writer, and the one
-leaf two units share: the forge's host holds one store identity for the token it
-publishes and the OIDC client secret it reads.
+`deploy.bao.reviewClassifierCommonName`, `deploy.bao.builderCommonName`,
+`deploy.bao.claudeLoginCommonName` and `deploy.bao.forgePublisherCommonName`.
+The last two are the writers, and the last is the one leaf two units share:
+the forge's host holds one store identity for the token it publishes and the
+OIDC client secret it reads.
 
-On a host that mints its own PKI, `glue-bao-tls.nix` signs all seven and defaults
-all fourteen options, and there is nothing to do. Elsewhere you copy each leaf from
+On a host that mints its own PKI, `glue-bao-tls.nix` signs all eight and defaults
+all sixteen options, and there is nothing to do. Elsewhere you copy each leaf from
 the store's host and name it here: a service principal's from the top of
 `/var/lib/swarm-bao-pki/`, another hive's queue-agent pair from
 `/var/lib/swarm-bao-pki/hives/<hive>/` ([bao.md § TLS](bao.md#tls) lists that
 directory). That's one file per principal rather than one file
-shared by seven, which is the whole of what this buys. `swarm-ci-runner.nix`
+shared by eight, which is the whole of what this buys. `swarm-ci-runner.nix`
 refuses the build wherever the runner runs without its pair, as
 `swarm-review-classifier.nix` does for the classifier and `swarm-grafana.nix`
 for Grafana. The forge's pair refuses nothing: without
@@ -448,7 +450,7 @@ naming both options, and the controller runs without forge access and the forge
 without a login source until an operator places the leaf.
 
 On a host without the store, where the forwarder never runs, forgetting one of
-the other seven isn't a quiet degrade. A hand-configured remote-store hive that
+the other eight isn't a quiet degrade. A hand-configured remote-store hive that
 names the hive's own `clientCertFile` and misses a principal's pair has the
 build refused, by the module of the reader it missed, naming that pair — see
 [what a missing leaf costs](#what-a-missing-leaf-costs) below.
diff --git a/docs/swarm/services.md b/docs/swarm/services.md
index 6757ec9e..e4294da1 100644
--- a/docs/swarm/services.md
+++ b/docs/swarm/services.md
@@ -330,3 +330,23 @@ secret store by name, under its own `review-classifier` leaf. On a host
 without the store, that leaf is the one file to copy, as for the CI runner.
 The swarm UI's try-out drives it through swarm-controller; what a run is
 and what it costs are in [`review-classifier.md`](review-classifier.md).
+
+### Claude login minter
+
+The claude login minter, in a `swarm-claude-login` container on the host that
+sets `deploy.claude-login.enable`. `allSwarmServices` defaults it on wherever
+the host has the minter's store identity, on the review classifier's terms.
+Run one: a login in progress lives in the service's memory between its start
+and its code.
+
+An operator logs an agent in from the **log in** button on its card in the
+swarm UI. swarm-controller relays the start and the pasted code over the queue,
+the minter runs `claude auth login` and writes the credentials to the agent's
+`swarm/agents/<agent>/claude-credentials`, and the agent's harness installs a
+version newer than the one it installed last.
+
+It needs neither the forge nor a hive on its host. It reaches the queue and the
+secret store by name, under its own `claude-login` leaf, and reaches claude's
+login endpoints over the network. On a host without the store, that leaf is
+the one file to copy, as for the CI runner. The flow and the version rule are
+in [`claude-login.md`](claude-login.md).
diff --git a/docs/swarm/ui.md b/docs/swarm/ui.md
index a6634db5..da523eab 100644
--- a/docs/swarm/ui.md
+++ b/docs/swarm/ui.md
@@ -22,8 +22,11 @@ domain, covers host-level detail for one hive.
 Everything it shows comes from [`swarm-controller`](../../swarm-controller/README.md).
 An agent created here or with `swarmctl agent create` starts `paused`; set it
 `up` from its card. A card shows **login needed** when the agent's own
-turn-state header says its claude has no session. Log it in from the agent's
-own web UI.
+turn-state header says its claude has no session, and a **log in** button
+that runs the claude login from a dialog: open the URL it shows, then paste
+the code back. The credentials go to the agent through the secret store
+([`claude-login.md`](claude-login.md)). The agent's own web UI login still
+works too.
 
 ### Agent and subagent terminals
 
diff --git a/flake.nix b/flake.nix
index b63c8148..095af5dd 100644
--- a/flake.nix
+++ b/flake.nix
@@ -172,6 +172,9 @@
               services.hyperhive.deploy.builder.package =
                 lib.mkDefault
                   self.packages.${pkgs.stdenv.hostPlatform.system}.swarm-builder;
+              services.hyperhive.deploy.claude-login.package =
+                lib.mkDefault
+                  self.packages.${pkgs.stdenv.hostPlatform.system}.swarm-claude-login;
               services.hyperhive.deploy.authelia.bridgePackage =
                 lib.mkDefault
                   self.packages.${pkgs.stdenv.hostPlatform.system}.swarm-authelia-bridge;
diff --git a/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.css b/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.css
new file mode 100644
index 00000000..d8b07af4
--- /dev/null
+++ b/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.css
@@ -0,0 +1,13 @@
+/* <ClaudeLoginDialog> — the code form's column, as
+   `LinkMatrixAccountForm.css` lays its form out. */
+.claude-login-form {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 0.75em;
+  margin-top: 1em;
+}
+.claude-login-ok {
+  margin-top: 1em;
+  color: var(--green);
+}
diff --git a/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.tsx b/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.tsx
new file mode 100644
index 00000000..fa91a72e
--- /dev/null
+++ b/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.tsx
@@ -0,0 +1,130 @@
+// <ClaudeLoginDialog> — logs one agent in to claude through the swarm's
+// login minter. Opening it starts the login (`POST …/claude-login`), which
+// answers with the URL claude printed; the operator opens it and pastes the
+// code back (`POST …/claude-login/code`). Closing it while the code is
+// still awaited stops the login (`DELETE …/claude-login`).
+//
+// Mounted only while open, so each open is a fresh login.
+import { useEffect, useState } from "preact/hooks";
+import { ApiErrorPanel } from "@hive/shared/api-error-panel.js";
+import { readApiError, type ProblemDetails } from "@hive/shared/api-error.js";
+import { Button } from "../../ui/button/Button.js";
+import { Dialog } from "../../ui/dialog/Dialog.js";
+import { Panel } from "../../ui/panel/Panel.js";
+import { TextField } from "../../ui/text-field/TextField.js";
+import {
+  afterCode,
+  afterStart,
+  claudeLoginPath,
+  leavesLoginRunning,
+  pastedCode,
+  type LoginStep,
+} from "./ClaudeLoginSteps.js";
+import "./ClaudeLoginDialog.css";
+
+async function problemOf(r: Response): Promise<ProblemDetails | null> {
+  return r.ok ? null : await readApiError(r);
+}
+
+export function ClaudeLoginDialog({
+  agent,
+  onClose,
+}: {
+  agent: string;
+  onClose: () => void;
+}) {
+  const [step, setStep] = useState<LoginStep>({ step: "starting" });
+  const [code, setCode] = useState("");
+
+  useEffect(() => {
+    let live = true;
+    void (async () => {
+      try {
+        const r = await fetch(claudeLoginPath(agent), { method: "POST" });
+        const problem = await problemOf(r);
+        const next = afterStart(
+          problem ? { problem } : ((await r.json()) as { url: string }),
+        );
+        if (live) setStep(next);
+      } catch (err) {
+        if (live) setStep(afterStart({ problem: { detail: String(err) } }));
+      }
+    })();
+    return () => {
+      live = false;
+    };
+  }, [agent]);
+
+  function close() {
+    if (leavesLoginRunning(step)) {
+      void fetch(claudeLoginPath(agent), { method: "DELETE" });
+    }
+    onClose();
+  }
+
+  async function submit(e: Event) {
+    e.preventDefault();
+    const pasted = pastedCode(code);
+    if (step.step !== "code" || pasted === null) return;
+    const { url } = step;
+    setStep({ step: "submitting", url });
+    try {
+      const r = await fetch(claudeLoginPath(agent, true), {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ code: pasted }),
+      });
+      setStep(afterCode(await problemOf(r)));
+    } catch (err) {
+      setStep(afterCode({ detail: String(err) }));
+    }
+    setCode("");
+  }
+
+  return (
+    <Dialog open onClose={close} label={`log ${agent} in to claude`} plain>
+      <Panel title={`log in to claude — ${agent}`} icon="🔑" onClose={close}>
+        {step.step === "starting" && <p>starting the login…</p>}
+        {(step.step === "code" || step.step === "submitting") && (
+          <>
+            <p>
+              Open{" "}
+              <a href={step.url} target="_blank" rel="noopener noreferrer">
+                the claude login page
+              </a>
+              , sign in with this agent's account, and paste the code it shows.
+            </p>
+            <form class="claude-login-form" onSubmit={submit}>
+              <TextField
+                id="claude-login-code"
+                label="code"
+                value={code}
+                required
+                onInput={setCode}
+              />
+              <Button
+                variant="primary"
+                type="submit"
+                disabled={step.step === "submitting"}
+              >
+                {step.step === "submitting" ? "logging in…" : "log in"}
+              </Button>
+            </form>
+          </>
+        )}
+        {step.step === "stored" && (
+          <p class="claude-login-ok">
+            Stored. <strong>{agent}</strong> picks the login up within a minute
+            and resumes.
+          </p>
+        )}
+        {step.step === "failed" && (
+          <ApiErrorPanel
+            context="the claude login failed; close and start again"
+            problem={step.problem}
+          />
+        )}
+      </Panel>
+    </Dialog>
+  );
+}
diff --git a/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginSteps.ts b/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginSteps.ts
new file mode 100644
index 00000000..5366130b
--- /dev/null
+++ b/frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginSteps.ts
@@ -0,0 +1,42 @@
+// The claude login dialog's steps, kept out of the component so `npm test`
+// runs them. The routes are swarm-controller's `claude_login` module.
+import type { ProblemDetails } from "@hive/shared/api-error.js";
+
+export type LoginStep =
+  | { step: "starting" }
+  | { step: "code"; url: string }
+  | { step: "submitting"; url: string }
+  | { step: "stored" }
+  | { step: "failed"; problem: ProblemDetails };
+
+export function claudeLoginPath(agent: string, code = false): string {
+  return `/api/agents/${encodeURIComponent(agent)}/claude-login${code ? "/code" : ""}`;
+}
+
+// The step after the start answered: its URL, or why there is none.
+export function afterStart(
+  answer: { url: string } | { problem: ProblemDetails },
+): LoginStep {
+  return "url" in answer
+    ? { step: "code", url: answer.url }
+    : { step: "failed", problem: answer.problem };
+}
+
+// The step after the code was posted. The minter ends the login on a
+// refused code, so the next attempt is a fresh start.
+export function afterCode(problem: ProblemDetails | null): LoginStep {
+  return problem === null ? { step: "stored" } : { step: "failed", problem };
+}
+
+// Whether closing the dialog leaves a login running that should be
+// stopped.
+export function leavesLoginRunning(s: LoginStep): boolean {
+  return s.step === "code";
+}
+
+// What the code form may submit: the pasted code without surrounding
+// whitespace, or nothing.
+export function pastedCode(raw: string): string | null {
+  const code = raw.trim();
+  return code === "" ? null : code;
+}
diff --git a/frontend/packages/swarm-ui/src/agent/roster/AgentCard.css b/frontend/packages/swarm-ui/src/agent/roster/AgentCard.css
index dd1a86e2..4ceb20ec 100644
--- a/frontend/packages/swarm-ui/src/agent/roster/AgentCard.css
+++ b/frontend/packages/swarm-ui/src/agent/roster/AgentCard.css
@@ -17,6 +17,13 @@
   gap: 0.4em;
   margin-left: auto;
 }
+/* The "login needed" badge and its "log in" button, kept together; the
+   wrapper also keeps their clicks, and the dialog's, off the card. */
+.ui-agent-card-login {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.4em;
+}
 .ui-agent-card-message {
   color: var(--muted);
   white-space: normal;
diff --git a/frontend/packages/swarm-ui/src/agent/roster/AgentCard.tsx b/frontend/packages/swarm-ui/src/agent/roster/AgentCard.tsx
index 23dbe3e4..2a3fa6e0 100644
--- a/frontend/packages/swarm-ui/src/agent/roster/AgentCard.tsx
+++ b/frontend/packages/swarm-ui/src/agent/roster/AgentCard.tsx
@@ -12,11 +12,13 @@
 // `WantedMenu` below keeps its own clicks (mouse or keyboard-synthesized,
 // `WantedMenu` hosts real `<button>`s) from also firing `Card`'s
 // `onClick` and opening the detail panel.
+import { useState } from "preact/hooks";
 import { Badge } from "@hive/shared/badge.js";
 import type { ProblemDetails } from "@hive/shared/api-error.js";
 import { Card } from "../../ui/card/Card.js";
 import { RelativeTime } from "../../ui/relative-time/RelativeTime.js";
 import { AgentIcon } from "../AgentIcon.js";
+import { ClaudeLoginDialog } from "../claude-login/ClaudeLoginDialog.js";
 import { FRESHNESS, showsLoginNeeded, type AgentRow } from "../AgentTypes.js";
 import { WantedMenu } from "./WantedMenu.js";
 import "./AgentCard.css";
@@ -45,6 +47,7 @@ export function AgentCard({
   onOpenDetail: (row: AgentRow) => void;
 }) {
   const { tone, label } = FRESHNESS[row.freshness];
+  const [loggingIn, setLoggingIn] = useState(false);
   return (
     <Card selected={selected} onClick={() => onOpenDetail(row)}>
       <div class="ui-agent-card-row">
@@ -72,11 +75,28 @@ export function AgentCard({
               }
             />
             {showsLoginNeeded(row) ? (
-              <Badge
-                tone="warning"
-                value="login needed"
-                title="the agent's claude has no session; its turns wait until it is logged in"
-              />
+              <span
+                class="ui-agent-card-login"
+                onClick={(e) => e.stopPropagation()}
+              >
+                <Badge
+                  tone="warning"
+                  value="login needed"
+                  title="the agent's claude has no session; its turns wait until it is logged in"
+                />
+                <Badge
+                  variant="quiet"
+                  value="log in"
+                  title={`log ${row.name} in to claude from here`}
+                  onClick={() => setLoggingIn(true)}
+                />
+                {loggingIn ? (
+                  <ClaudeLoginDialog
+                    agent={row.name}
+                    onClose={() => setLoggingIn(false)}
+                  />
+                ) : null}
+              </span>
             ) : null}
             <span
               class="ui-agent-card-wanted"
diff --git a/frontend/packages/swarm-ui/test/claude-login.test.mjs b/frontend/packages/swarm-ui/test/claude-login.test.mjs
new file mode 100644
index 00000000..e61e05ff
--- /dev/null
+++ b/frontend/packages/swarm-ui/test/claude-login.test.mjs
@@ -0,0 +1,54 @@
+// The claude login dialog's step logic. Run by `npm test`, which Node runs
+// with its built-in test runner and type stripping, so the `.ts` module is
+// imported as it is.
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import {
+  afterCode,
+  afterStart,
+  claudeLoginPath,
+  leavesLoginRunning,
+  pastedCode,
+} from "../src/agent/claude-login/ClaudeLoginSteps.ts";
+
+test("the routes name the agent, escaped", () => {
+  assert.equal(claudeLoginPath("atlas"), "/api/agents/atlas/claude-login");
+  assert.equal(
+    claudeLoginPath("atlas", true),
+    "/api/agents/atlas/claude-login/code",
+  );
+  assert.equal(claudeLoginPath("a/b"), "/api/agents/a%2Fb/claude-login");
+});
+
+test("a started login asks for the code at its URL", () => {
+  assert.deepEqual(afterStart({ url: "https://claude.ai/oauth/x" }), {
+    step: "code",
+    url: "https://claude.ai/oauth/x",
+  });
+});
+
+test("a start that failed shows why and has no URL", () => {
+  const problem = { detail: "no claude login minter is listening" };
+  assert.deepEqual(afterStart({ problem }), { step: "failed", problem });
+});
+
+test("an accepted code is stored; a refused one is a failure", () => {
+  assert.deepEqual(afterCode(null), { step: "stored" });
+  const problem = { detail: "OAuth error: invalid code" };
+  assert.deepEqual(afterCode(problem), { step: "failed", problem });
+});
+
+test("only a login waiting for its code is stopped on close", () => {
+  assert.equal(leavesLoginRunning({ step: "code", url: "https://u" }), true);
+  assert.equal(leavesLoginRunning({ step: "starting" }), false);
+  assert.equal(
+    leavesLoginRunning({ step: "submitting", url: "https://u" }),
+    false,
+  );
+  assert.equal(leavesLoginRunning({ step: "stored" }), false);
+});
+
+test("a pasted code is trimmed, and a blank one is nothing", () => {
+  assert.equal(pastedCode("  abc-def \n"), "abc-def");
+  assert.equal(pastedCode(" \n "), null);
+});
diff --git a/hive-agent/src/claude_credentials.rs b/hive-agent/src/claude_credentials.rs
new file mode 100644
index 00000000..81797f43
--- /dev/null
+++ b/hive-agent/src/claude_credentials.rs
@@ -0,0 +1,305 @@
+//! The claude credentials the swarm's login minter stored for this agent, at
+//! `swarm/agents/<agent>/claude-credentials`, read under the agent's own
+//! certificate while it waits for a login ([`crate::login::wait_for_login`]).
+//!
+//! ⚠️ **Installed only when the store's version is newer than the last one
+//! installed here**, never because the bytes differ. `claude` rotates the
+//! refresh token in `~/.claude/.credentials.json`, so after its first refresh
+//! the stored copy is stale; putting it back would end the rotated session.
+//! The last installed version is kept in [`VERSION_FILE`] under the harness
+//! dir. A credentials file `wait_for_login` sees land resumes the agent as a
+//! web-UI login does.
+
+use std::future::Future;
+use std::path::{Path, PathBuf};
+use std::time::Duration;
+
+use anyhow::Context as _;
+use swarm_secret_client::{
+    SecretStore,
+    claude_login::{Credentials, credentials_path},
+    client::DEFAULT_CERT_MOUNT,
+};
+
+/// The file under the harness dir holding the last installed version.
+pub const VERSION_FILE: &str = "claude-credentials-version";
+
+/// How often a waiting agent asks the store.
+pub const POLL_INTERVAL: Duration = Duration::from_secs(30);
+
+/// How long one read of the store may take.
+const STORE_READ_TIMEOUT: Duration = Duration::from_secs(10);
+
+/// The file `claude` reads its session from.
+const CREDENTIALS_FILE: &str = ".credentials.json";
+
+/// Whether a stored `version` replaces what is installed: only a version
+/// newer than the last one installed, or any when none has been.
+#[must_use]
+pub fn is_newer(stored: u64, installed: Option<u64>) -> bool {
+    installed.is_none_or(|last| stored > last)
+}
+
+/// What one [`Pickup::check`] did.
+#[derive(Debug, PartialEq, Eq)]
+pub enum Outcome {
+    /// Nothing is stored for this agent.
+    NothingStored,
+    /// The stored version is not newer than the installed one.
+    NotNewer { stored: u64, installed: u64 },
+    /// The stored version is installed now.
+    Installed { version: u64 },
+}
+
+/// Where [`Pickup`] reads from. A trait so the guard can be exercised without
+/// a store.
+pub trait Source: Send + Sync {
+    /// The stored credentials and their version, or `None` when nothing is
+    /// stored.
+    fn fetch(&self) -> impl Future<Output = anyhow::Result<Option<(Credentials, u64)>>> + Send;
+}
+
+/// The agent's own leaf, read under its own certificate.
+pub struct Store {
+    settings: swarm_secret_client::client::Settings,
+    role: String,
+    path: String,
+}
+
+impl Source for Store {
+    async fn fetch(&self) -> anyhow::Result<Option<(Credentials, u64)>> {
+        let read = async {
+            let store = SecretStore::connect(&self.settings, &self.role, DEFAULT_CERT_MOUNT)
+                .await
+                .context("logging in to the swarm secret store as this agent")?;
+            store
+                .read_versioned(&self.path)
+                .await
+                .with_context(|| format!("reading {}", self.path))
+        };
+        tokio::time::timeout(STORE_READ_TIMEOUT, read)
+            .await
+            .with_context(|| format!("no answer from the store within {STORE_READ_TIMEOUT:?}"))?
+    }
+}
+
+impl Store {
+    /// This agent's leaf, from the environment `crate::swarm_queue` reads.
+    ///
+    /// # Errors
+    /// A store coordinate is missing.
+    pub fn from_env() -> anyhow::Result<Self> {
+        let (settings, role, agent) = crate::swarm_queue::agent_store(|k| std::env::var(k).ok())?;
+        Ok(Self {
+            settings,
+            role,
+            path: credentials_path(&agent)?,
+        })
+    }
+}
+
+/// Installs the stored credentials into `claude_dir` when they are newer.
+pub struct Pickup<S> {
+    source: S,
+    claude_dir: PathBuf,
+    version_file: PathBuf,
+}
+
+impl<S: Source> Pickup<S> {
+    pub fn new(source: S, claude_dir: PathBuf, version_file: PathBuf) -> Self {
+        Self {
+            source,
+            claude_dir,
+            version_file,
+        }
+    }
+
+    /// Read the store once and install what it holds if it is newer.
+    ///
+    /// # Errors
+    /// The store read failed, or writing the credentials or the version did.
+    pub async fn check(&self) -> anyhow::Result<Outcome> {
+        let Some((credentials, stored)) = self.source.fetch().await? else {
+            return Ok(Outcome::NothingStored);
+        };
+        let installed = read_version(&self.version_file)?;
+        if !is_newer(stored, installed) {
+            return Ok(Outcome::NotNewer {
+                stored,
+                installed: installed.unwrap_or_default(),
+            });
+        }
+        write_private(
+            &self.claude_dir.join(CREDENTIALS_FILE),
+            credentials.value.as_bytes(),
+        )
+        .context("installing the stored claude credentials")?;
+        write_private(&self.version_file, stored.to_string().as_bytes())
+            .context("recording the installed credentials version")?;
+        Ok(Outcome::Installed { version: stored })
+    }
+}
+
+/// The version recorded in `file`, or `None` when there is no file.
+fn read_version(file: &Path) -> anyhow::Result<Option<u64>> {
+    match std::fs::read_to_string(file) {
+        Ok(s) => s
+            .trim()
+            .parse()
+            .map(Some)
+            .with_context(|| format!("{} does not hold a version", file.display())),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(None),
+        Err(e) => Err(e).with_context(|| format!("reading {}", file.display())),
+    }
+}
+
+/// Replace `path` with `bytes`, mode 0600, through a sibling temp file so a
+/// reader never sees half of it.
+fn write_private(path: &Path, bytes: &[u8]) -> std::io::Result<()> {
+    use std::io::Write as _;
+    use std::os::unix::fs::OpenOptionsExt as _;
+
+    let mut tmp = path.as_os_str().to_owned();
+    tmp.push(".tmp");
+    let tmp = PathBuf::from(tmp);
+    let mut f = std::fs::OpenOptions::new()
+        .write(true)
+        .create(true)
+        .truncate(true)
+        .mode(0o600)
+        .open(&tmp)?;
+    f.write_all(bytes)?;
+    f.sync_all()?;
+    std::fs::rename(&tmp, path)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Mutex;
+
+    use super::*;
+
+    struct Fake(Mutex<Option<(String, u64)>>);
+
+    impl Source for Fake {
+        async fn fetch(&self) -> anyhow::Result<Option<(Credentials, u64)>> {
+            Ok(self
+                .0
+                .lock()
+                .expect("lock")
+                .clone()
+                .map(|(value, v)| (Credentials { value }, v)))
+        }
+    }
+
+    struct Dir(PathBuf);
+
+    impl Drop for Dir {
+        fn drop(&mut self) {
+            let _ = std::fs::remove_dir_all(&self.0);
+        }
+    }
+
+    fn dir(name: &str) -> Dir {
+        let d = std::env::temp_dir().join(format!(
+            "hive-agent-claude-credentials-{name}-{}",
+            std::process::id()
+        ));
+        let _ = std::fs::remove_dir_all(&d);
+        std::fs::create_dir_all(d.join("claude")).expect("temp dir");
+        Dir(d)
+    }
+
+    fn pickup(d: &Dir, stored: Option<(&str, u64)>) -> Pickup<Fake> {
+        Pickup::new(
+            Fake(Mutex::new(stored.map(|(v, n)| (v.to_owned(), n)))),
+            d.0.join("claude"),
+            d.0.join(VERSION_FILE),
+        )
+    }
+
+    fn installed(d: &Dir) -> Option<String> {
+        std::fs::read_to_string(d.0.join("claude").join(CREDENTIALS_FILE)).ok()
+    }
+
+    #[test]
+    fn only_a_newer_version_replaces_the_installed_one() {
+        assert!(is_newer(1, None));
+        assert!(is_newer(3, Some(2)));
+        assert!(
+            !is_newer(2, Some(2)),
+            "an equal version was installed again"
+        );
+        assert!(!is_newer(1, Some(2)), "an older version was installed");
+    }
+
+    #[tokio::test]
+    async fn the_first_stored_version_is_installed_private_and_recorded() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let d = dir("first");
+        let p = pickup(&d, Some(("{\"v\":1}", 1)));
+        assert_eq!(
+            p.check().await.expect("check"),
+            Outcome::Installed { version: 1 }
+        );
+        assert_eq!(installed(&d).as_deref(), Some("{\"v\":1}"));
+        let mode = std::fs::metadata(d.0.join("claude").join(CREDENTIALS_FILE))
+            .expect("installed")
+            .permissions()
+            .mode();
+        assert_eq!(mode & 0o777, 0o600);
+        assert_eq!(
+            read_version(&d.0.join(VERSION_FILE)).expect("read"),
+            Some(1)
+        );
+    }
+
+    #[tokio::test]
+    async fn an_equal_or_older_version_leaves_the_rotated_session_alone() {
+        let d = dir("stale");
+        let p = pickup(&d, Some(("{\"v\":2}", 2)));
+        p.check().await.expect("first install");
+        // claude refreshes the session in place.
+        std::fs::write(d.0.join("claude").join(CREDENTIALS_FILE), "rotated").expect("refresh");
+        assert_eq!(
+            p.check().await.expect("check"),
+            Outcome::NotNewer {
+                stored: 2,
+                installed: 2
+            }
+        );
+        *p.source.0.lock().expect("lock") = Some(("{\"v\":1}".to_owned(), 1));
+        assert_eq!(
+            p.check().await.expect("check"),
+            Outcome::NotNewer {
+                stored: 1,
+                installed: 2
+            }
+        );
+        assert_eq!(installed(&d).as_deref(), Some("rotated"));
+    }
+
+    #[tokio::test]
+    async fn a_relogin_is_installed_over_the_rotated_session() {
+        let d = dir("relogin");
+        let p = pickup(&d, Some(("{\"v\":1}", 1)));
+        p.check().await.expect("first install");
+        std::fs::write(d.0.join("claude").join(CREDENTIALS_FILE), "rotated").expect("refresh");
+        *p.source.0.lock().expect("lock") = Some(("{\"v\":2}".to_owned(), 2));
+        assert_eq!(
+            p.check().await.expect("check"),
+            Outcome::Installed { version: 2 }
+        );
+        assert_eq!(installed(&d).as_deref(), Some("{\"v\":2}"));
+    }
+
+    #[tokio::test]
+    async fn nothing_stored_installs_nothing() {
+        let d = dir("empty");
+        let p = pickup(&d, None);
+        assert_eq!(p.check().await.expect("check"), Outcome::NothingStored);
+        assert_eq!(installed(&d), None);
+        assert_eq!(read_version(&d.0.join(VERSION_FILE)).expect("read"), None);
+    }
+}
diff --git a/hive-agent/src/login.rs b/hive-agent/src/login.rs
index a10284c5..2a953977 100644
--- a/hive-agent/src/login.rs
+++ b/hive-agent/src/login.rs
@@ -15,6 +15,7 @@ use std::sync::{Arc, Mutex};
 use std::time::{Duration, SystemTime};
 
 use crate::events::Bus;
+use crate::{claude_credentials, paths};
 
 /// Returns the Claude credentials directory for this agent. Delegates
 /// to `paths::claude_dir`, which reads `$HOME/.claude`. The service
@@ -178,7 +179,25 @@ pub async fn wait_for_login(
     // re-trigger the fallback on every iteration.
     let baseline_unreadable = unreadable_mtime_names(claude_dir);
     let probe = Duration::from_millis(poll_ms.max(2000));
+    let pickup = swarm_pickup(claude_dir);
+    let mut next_pickup = tokio::time::Instant::now();
     loop {
+        if let Some(pickup) = &pickup
+            && tokio::time::Instant::now() >= next_pickup
+        {
+            next_pickup = tokio::time::Instant::now() + claude_credentials::POLL_INTERVAL;
+            match pickup.check().await {
+                Ok(claude_credentials::Outcome::Installed { version }) => tracing::info!(
+                    version,
+                    "installed the claude credentials the swarm login stored"
+                ),
+                Ok(outcome) => tracing::debug!(?outcome, "no newer swarm claude credentials"),
+                Err(e) => tracing::warn!(
+                    error = %format!("{e:#}"),
+                    "checking the swarm store for claude credentials failed"
+                ),
+            }
+        }
         tokio::time::sleep(probe).await;
         // A login that already landed by the time this first poll runs
         // (the race this baseline design closes) is caught here on the
@@ -193,6 +212,27 @@ pub async fn wait_for_login(
     }
 }
 
+/// The swarm-login pickup for `claude_dir`, or `None` when this process has
+/// no store to read from.
+fn swarm_pickup(
+    claude_dir: &Path,
+) -> Option<claude_credentials::Pickup<claude_credentials::Store>> {
+    match claude_credentials::Store::from_env() {
+        Ok(store) => Some(claude_credentials::Pickup::new(
+            store,
+            claude_dir.to_owned(),
+            paths::harness_dir().join(claude_credentials::VERSION_FILE),
+        )),
+        Err(e) => {
+            tracing::warn!(
+                error = %format!("{e:#}"),
+                "no swarm store coordinates, so a swarm login cannot reach this agent"
+            );
+            None
+        }
+    }
+}
+
 /// Names of credential files (see [`CRED_FILE_NAMES`]) currently present in
 /// `dir` whose mtime is *not* readable (`metadata()`/`modified()` errors —
 /// exotic fs, NFS quirks). Used once, at [`wait_for_login`]'s entry, as the
diff --git a/hive-agent/src/main.rs b/hive-agent/src/main.rs
index 012bdbfd..ded89a04 100644
--- a/hive-agent/src/main.rs
+++ b/hive-agent/src/main.rs
@@ -10,6 +10,7 @@
 //! before lib + bin were collapsed into one) plus the serve loop.
 
 mod boot_announce;
+mod claude_credentials;
 mod claude_md_watch;
 mod claude_usage_watch;
 mod db_migrate;
diff --git a/hive-agent/src/swarm_queue.rs b/hive-agent/src/swarm_queue.rs
index b7df61d4..dffff2a4 100644
--- a/hive-agent/src/swarm_queue.rs
+++ b/hive-agent/src/swarm_queue.rs
@@ -210,10 +210,26 @@ impl<S: SecretSource> AgentSecret<S> {
 /// # Errors
 /// No store address, or one without the agent name or the identity beside it.
 fn store_source(get: impl Fn(&str) -> Option<String>) -> anyhow::Result<StoreSource> {
+    let (settings, role, agent) = agent_store(get)?;
+    Ok(StoreSource {
+        settings,
+        role,
+        path: queue::agent_queue_path(&agent)?,
+    })
+}
+
+/// Where the store is, the cert-auth role this agent logs in as, and the
+/// agent's name, from `get`.
+///
+/// # Errors
+/// No store address, or one without the agent name or the identity beside it.
+pub(crate) fn agent_store(
+    get: impl Fn(&str) -> Option<String>,
+) -> anyhow::Result<(Settings, String, String)> {
     if get(ENV_ADDR).is_none_or(|v| v.is_empty()) {
         anyhow::bail!(
             "{ENV_ADDR} is unset or empty, so there is no secret store to read this agent's \
-             queue credential from"
+             secrets from"
         );
     }
     let agent = get(ENV_AGENT_NAME)
@@ -221,11 +237,8 @@ fn store_source(get: impl Fn(&str) -> Option<String>) -> anyhow::Result<StoreSou
         .with_context(|| format!("{ENV_AGENT_NAME} is unset or empty"))?;
     let settings = Settings::from_lookup(|k| get(k).filter(|v| k != ENV_CACERT || ca_is_usable(v)))
         .context("reading the swarm secret store's coordinates from the environment")?;
-    Ok(StoreSource {
-        settings,
-        role: policy::agent_object_name(&agent)?,
-        path: queue::agent_queue_path(&agent)?,
-    })
+    let role = policy::agent_object_name(&agent)?;
+    Ok((settings, role, agent))
 }
 
 /// Whether the CA bundle at `path` is a file with bytes in it. `BAO_CACERT`
diff --git a/nix/host-modules/default.nix b/nix/host-modules/default.nix
index 14cb6129..cc376b0e 100644
--- a/nix/host-modules/default.nix
+++ b/nix/host-modules/default.nix
@@ -47,6 +47,7 @@
     ./glue-nats-wireguard.nix
     ./glue-queue-agent-credential.nix
     ./glue-builder-oidc-client.nix
+    ./glue-claude-login-oidc-client.nix
     ./glue-review-classifier-oidc-client.nix
     ./glue-secret-publisher-authelia.nix
     ./glue-secret-publisher-bao-identity.nix
@@ -57,6 +58,7 @@
     ./swarm-bao-service.nix
     ./swarm-bao.nix
     ./swarm-builder.nix
+    ./swarm-claude-login.nix
     ./swarm-ci-runner.nix
     ./swarm-review-classifier.nix
     ./swarm-secret-publisher.nix
diff --git a/nix/host-modules/deploy.nix b/nix/host-modules/deploy.nix
index 7791e721..60742496 100644
--- a/nix/host-modules/deploy.nix
+++ b/nix/host-modules/deploy.nix
@@ -700,6 +700,26 @@ in
       '';
     };
 
+    claude-login.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = ''
+        Run the claude login minter in a `swarm-claude-login` container on
+        this host. It runs `claude auth login` for the agent an operator logs
+        in from its card in the swarm UI, and writes the credentials to that
+        agent's `secret/swarm/agents/<agent>/claude-credentials`, which the
+        agent's harness installs. Run it on one host: a login in progress
+        lives in the service's memory.
+
+        On by default where
+        {option}`services.hyperhive.deploy.allSwarmServices` is set and this
+        host has the minter's store identity (the pair
+        {option}`services.hyperhive.deploy.bao.claudeLoginClientCertFile`
+        and `claudeLoginClientKeyFile`, minted on the store's host).
+      '';
+    };
+
     builder.enable = lib.mkOption {
       type = lib.types.bool;
       default = false;
diff --git a/nix/host-modules/glue-bao-tls.nix b/nix/host-modules/glue-bao-tls.nix
index 482609ce..e8d8b96c 100644
--- a/nix/host-modules/glue-bao-tls.nix
+++ b/nix/host-modules/glue-bao-tls.nix
@@ -117,6 +117,8 @@ in
       reviewClassifierClientKeyFile = lib.mkDefault "${pkiDir}/review-classifier-key.pem";
       builderClientCertFile = lib.mkDefault "${pkiDir}/builder.pem";
       builderClientKeyFile = lib.mkDefault "${pkiDir}/builder-key.pem";
+      claudeLoginClientCertFile = lib.mkDefault "${pkiDir}/claude-login.pem";
+      claudeLoginClientKeyFile = lib.mkDefault "${pkiDir}/claude-login-key.pem";
       forgePublisherClientCertFile = lib.mkDefault "${pkiDir}/forge-publisher.pem";
       forgePublisherClientKeyFile = lib.mkDefault "${pkiDir}/forge-publisher-key.pem";
       servicesIssuerClientCertFile = lib.mkDefault "${pkiDir}/services-issuer.pem";
@@ -303,6 +305,13 @@ in
         [ -s ${pkiDir}/builder.pem ] || ${signLeaf} ${pkiDir} builder \
           ${lib.escapeShellArg deployCfg.bao.builderCommonName} "" clientAuth
 
+        # The claude login minter's, which writes agents' claude credentials
+        # and reads its queue client secret. Minted here for the matrix-ctl
+        # leaf's reason: the minter is a swarm service, so on a minter host
+        # without the store this is the file an operator copies.
+        [ -s ${pkiDir}/claude-login.pem ] || ${signLeaf} ${pkiDir} claude-login \
+          ${lib.escapeShellArg deployCfg.bao.claudeLoginCommonName} "" clientAuth
+
         # The forge's token publisher. Minted here for the matrix-ctl leaf's
         # reason: the forge is a swarm singleton, so on a forge host without the
         # store this is the file an operator copies.
diff --git a/nix/host-modules/glue-claude-login-oidc-client.nix b/nix/host-modules/glue-claude-login-oidc-client.nix
new file mode 100644
index 00000000..88dc2af2
--- /dev/null
+++ b/nix/host-modules/glue-claude-login-oidc-client.nix
@@ -0,0 +1,35 @@
+# Glue: register the claude login minter as an OIDC client wherever authelia
+# runs.
+#
+# ONE PAIRING PER FILE — swarm-claude-login ← authelia, and nothing else.
+# Deleting this leaves a minter whose token requests authelia answers with a
+# 401, and no minted secret for swarm-secret-publish to put in the store.
+#
+# ⚠️ Gated on authelia being HERE, and NOT on this host running the minter,
+# for ./glue-controller-oidc-client.nix's reason: a client is a row in THIS
+# host's provider config. Registered whether or not any host enables the
+# minter: nothing in `swarm.*` records that, so a swarm without one carries
+# one unused client and one unused minted secret.
+{
+  lib,
+  config,
+  ...
+}:
+let
+  hyperhiveCfg = config.services.hyperhive;
+  deployCfg = hyperhiveCfg.deploy;
+  clientId = hyperhiveCfg.swarm.claude-login.clientId;
+in
+{
+  config = lib.mkIf deployCfg.authelia.enable {
+    services.hyperhive.swarm.authelia.oidc.clients = [
+      {
+        id = clientId;
+        description = "HyperHive claude login minter";
+        # `client_credentials`: a daemon authenticating as itself.
+        kind = "machine";
+        audience = [ clientId ];
+      }
+    ];
+  };
+}
diff --git a/nix/host-modules/swarm-bao.nix b/nix/host-modules/swarm-bao.nix
index 9ea83ad8..1d77b11c 100644
--- a/nix/host-modules/swarm-bao.nix
+++ b/nix/host-modules/swarm-bao.nix
@@ -1054,6 +1054,22 @@ let
     }
   ];
 
+  # The claude login minter: every agent's `claude-credentials` leaf,
+  # create and update so a relogin replaces the last, and nothing else under
+  # an agent; and its own queue client secret, read at start.
+  claudeLoginWriters = [
+    {
+      name = "swarm-claude-login";
+      cn = baoDeploy.claudeLoginCommonName;
+      policyText = ''
+        path "${credentialMountPath}/data/swarm/agents/+/claude-credentials" {
+          capabilities = ["create", "update"]
+        }
+      ''
+      + readStanza "${credentialMountPath}/data/swarm/services/${hyperhiveCfg.swarm.claude-login.clientId}/oidc/client";
+    }
+  ];
+
   # The forge host's one store identity. `swarm-bao-forge-publisher` writes
   # the controller's forge token under it, the one writer of that path and
   # write-only: it copies a file in and never reads one back.
@@ -1932,6 +1948,19 @@ in
       '';
     };
 
+    claudeLoginCommonName = lib.mkOption {
+      type = lib.types.str;
+      default = "swarm-claude-login";
+      description = ''
+        Subject the store's `swarm-claude-login` cert-auth role accepts: the
+        identity the claude login minter presents from inside its container.
+        Its grant is create and update on `swarm/agents/+/claude-credentials`
+        and read on its own queue client secret.
+
+        ⚠️ Reserved as a hive name by ./swarm.nix, like its siblings.
+      '';
+    };
+
     forgePublisherCommonName = lib.mkOption {
       type = lib.types.str;
       default = "swarm-forge-publisher";
@@ -2232,6 +2261,31 @@ in
       '';
     };
 
+    claudeLoginClientCertFile = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default = null;
+      example = "/var/lib/swarm-bao-pki/claude-login.pem";
+      description = ''
+        Certificate the claude login minter presents to the store. Its subject
+        must be {option}`services.hyperhive.deploy.bao.claudeLoginCommonName`.
+
+        ./glue-bao-tls.nix points it at the leaf it mints on the store's host.
+        On a minter host without the store, it is a file the operator copies
+        from the store's host. A path, never a value.
+      '';
+    };
+
+    claudeLoginClientKeyFile = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default = null;
+      example = "/var/lib/swarm-bao-pki/claude-login-key.pem";
+      description = ''
+        Private key for
+        {option}`services.hyperhive.deploy.bao.claudeLoginClientCertFile`.
+        A path, never a value.
+      '';
+    };
+
     forgePublisherClientCertFile = lib.mkOption {
       type = lib.types.nullOr lib.types.str;
       default = null;
@@ -3318,6 +3372,8 @@ in
 
       systemd.services.swarm-bao-builder-policy = readerPolicyUnit "write the swarm builder's forge-token-reader bao policy and cert-auth role" builderReaders;
 
+      systemd.services.swarm-bao-claude-login-policy = readerPolicyUnit "write the claude login minter's credentials-writer bao policy and cert-auth role" claudeLoginWriters;
+
       systemd.services.swarm-bao-forge-publisher-policy = readerPolicyUnit "write the forge's controller-token-publisher bao policy and cert-auth role" forgePublisherWriters;
 
       # A FOURTH sibling, same shape and same reasons as the two above. This
diff --git a/nix/host-modules/swarm-claude-login.nix b/nix/host-modules/swarm-claude-login.nix
new file mode 100644
index 00000000..29e15a14
--- /dev/null
+++ b/nix/host-modules/swarm-claude-login.nix
@@ -0,0 +1,203 @@
+# The claude login minter, in a `swarm-claude-login` container on the host
+# that sets `deploy.claude-login.enable`, which `deploy.allSwarmServices`
+# defaults on where the host has the minter's store identity. An operator logs
+# an agent in from its card in the swarm UI: swarm-controller relays the start
+# and the pasted code over the queue, and the daemon runs `claude auth login`
+# and writes the credentials to that agent's store leaf.
+# docs/swarm/claude-login.md has the design.
+#
+# Its own network namespace on the bridge, as ./swarm-review-classifier.nix
+# has: it reaches the swarm services by name and nothing on the host's
+# loopback.
+#
+# The container holds one credential, its own store leaf, which nspawn hands in
+# as a system credential with no copy on disk. The daemon reads its queue
+# client secret with it and writes agents' credentials under it.
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}:
+let
+  hyperhiveCfg = config.services.hyperhive;
+  cfg = hyperhiveCfg.deploy.claude-login;
+  baoCfg = hyperhiveCfg.swarm.bao;
+  baoDeploy = hyperhiveCfg.deploy.bao;
+  natsCfg = hyperhiveCfg.swarm.nats;
+  autheliaCfg = hyperhiveCfg.swarm.authelia;
+  gatewayCfg = hyperhiveCfg.gateway;
+  networkCfg = hyperhiveCfg.network;
+  tlsCfg = hyperhiveCfg.deploy.hive-controller.tls;
+
+  machine = "swarm-claude-login";
+  unit = "swarm-claude-login";
+  clientId = hyperhiveCfg.swarm.claude-login.clientId;
+
+  # The daemon reaches authelia, the store and the queue by name over TLS, and
+  # in self-signed mode their leaves chain to the hive CA.
+  caTrust = import ./lib/hive-ca-trust.nix { inherit lib tlsCfg gatewayCfg; };
+  caBundleModule = caTrust.trustBundle {
+    inherit pkgs;
+    name = machine;
+    consumers = [ unit ];
+  };
+
+  haveClientIdentity =
+    baoDeploy.claudeLoginClientCertFile != null && baoDeploy.claudeLoginClientKeyFile != null;
+
+  # Credential id → host source, as ./swarm-review-classifier.nix hands its
+  # leaf in.
+  storeFiles = lib.filterAttrs (_: source: source != null) {
+    claude-login-bao-cert = baoDeploy.claudeLoginClientCertFile;
+    claude-login-bao-key = baoDeploy.claudeLoginClientKeyFile;
+    claude-login-bao-server-ca = baoDeploy.serverCaFile;
+  };
+  # nixos-container expands `extraFlags` unquoted, so a source path must be
+  # one word.
+  oneWord = path: builtins.match ".*[[:space:]].*" path == null;
+  credential = id: "/run/credentials/${unit}.service/${id}";
+
+  privateNetwork = true;
+in
+{
+  options.services.hyperhive.swarm.claude-login.clientId = lib.mkOption {
+    type = lib.types.str;
+    readOnly = true;
+    default = "swarm-claude-login";
+    description = ''
+      The OAuth2 client id the claude login minter presents to the swarm
+      queue. Read-only: the host running authelia registers it, the queue's
+      auth-callout responder grants it the login subject, and the secret
+      publisher carries its secret to the store, all from this one value.
+    '';
+  };
+
+  options.services.hyperhive.deploy.claude-login.package = lib.mkOption {
+    type = lib.types.package;
+    defaultText = lib.literalExpression "hyperhive.packages.\${system}.swarm-claude-login";
+    description = "The claude login minter daemon package.";
+  };
+
+  config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = haveClientIdentity;
+        message = ''
+          services.hyperhive.deploy.claude-login.enable requires the minter's
+          swarm-secret-store client identity: set both
+
+            services.hyperhive.deploy.bao.claudeLoginClientCertFile
+            services.hyperhive.deploy.bao.claudeLoginClientKeyFile
+
+          The minter reads its queue client secret and writes agents' claude
+          credentials with it.
+
+          Both default to the pair glue-bao-tls.nix mints when
+          services.hyperhive.deploy.bao.enable is true (the host that runs the
+          store). Otherwise copy claude-login.pem and claude-login-key.pem from
+          the store host's /var/lib/swarm-bao-pki/ and name them in those two
+          options.
+        '';
+      }
+      {
+        assertion = lib.all oneWord (lib.attrValues storeFiles);
+        message = ''
+          The claude login minter's store identity paths must not contain
+          whitespace: nspawn's --load-credential receives them through
+          nixos-container's unquoted extra flags.
+        '';
+      }
+    ];
+
+    # The container hangs off the bridge, takes its address from the gateway's
+    # DHCP and resolves through its dnsmasq.
+    services.hyperhive.network.enable = lib.mkDefault true;
+    services.hyperhive.gateway.enable = lib.mkDefault true;
+    services.hyperhive.gateway.dns.enable = lib.mkDefault true;
+
+    # nspawn fails to start the container when a credential source is
+    # missing, so where this host mints the leaf the container waits for it.
+    systemd.services."container@${machine}" = lib.mkMerge [
+      caTrust.containerOrdering
+      { after = [ "swarm-bao-pki.service" ]; }
+    ];
+
+    containers.${machine} = {
+      autoStart = true;
+      # The daemon keeps no state; each login's scratch directory is under
+      # PrivateTmp.
+      ephemeral = false;
+      # Journal files on the host, not inside the container: nixpkgs hardcodes
+      # --link-journal=try-guest, and EXTRA_NSPAWN_FLAGS expands after it.
+      extraFlags = [
+        "--link-journal=host"
+      ]
+      ++ lib.mapAttrsToList (id: source: "--load-credential=${id}:${source}") storeFiles;
+      inherit privateNetwork;
+      hostBridge = networkCfg.bridgeName;
+      bindMounts = caTrust.bindMount;
+
+      config =
+        { pkgs, lib, ... }:
+        {
+          imports = [
+            ../container-modules/swarm-container.nix
+            caBundleModule
+          ];
+
+          services.hyperhive.swarmContainer = {
+            inherit privateNetwork;
+            writesOwnResolvConf = false;
+          };
+          networking.nameservers = [ networkCfg.bridgeIp ];
+          networking.interfaces.eth0.useDHCP = true;
+
+          # `claude-code` is unfree, and this container evaluates its own
+          # nixpkgs, so the host's allowance does not reach here.
+          nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [ "claude-code" ];
+
+          users.users.${unit} = {
+            isSystemUser = true;
+            group = unit;
+          };
+          users.groups.${unit} = { };
+
+          systemd.services.${unit} = {
+            description = "log agents in to claude for the swarm UI";
+            wantedBy = [ "multi-user.target" ];
+            wants = [ "network-online.target" ];
+            after = [ "network-online.target" ];
+            environment = {
+              BAO_ADDR = "https://${baoCfg.domain}:${toString baoCfg.port}";
+              BAO_CLIENT_CERT = credential "claude-login-bao-cert";
+              BAO_CLIENT_KEY = credential "claude-login-bao-key";
+              SWARM_CLAUDE_LOGIN_NATS_URL = "tls://${natsCfg.domain}:${toString natsCfg.port}";
+              SWARM_CLAUDE_LOGIN_OIDC_TOKEN_ENDPOINT = "${autheliaCfg.url}/api/oidc/token";
+              SWARM_CLAUDE_LOGIN_OIDC_CLIENT_ID = clientId;
+              SWARM_CLAUDE_LOGIN_CLAUDE = "${pkgs.claude-code}/bin/claude";
+            }
+            // lib.optionalAttrs (storeFiles ? claude-login-bao-server-ca) {
+              BAO_CACERT = credential "claude-login-bao-server-ca";
+            }
+            // lib.optionalAttrs caTrust.useSelfSigned {
+              SWARM_CLAUDE_LOGIN_OIDC_CA_FILE = caTrust.bundlePathFor machine;
+            };
+            serviceConfig = {
+              ExecStart = "${cfg.package}/bin/swarm-claude-login";
+              User = unit;
+              Group = unit;
+              # Each login's scratch directory, gone with the unit.
+              PrivateTmp = true;
+              UMask = "0077";
+              # Bare ids: the system credentials nspawn handed in.
+              LoadCredential = lib.attrNames storeFiles;
+              Restart = "on-failure";
+              RestartSec = "10s";
+              SyslogIdentifier = unit;
+            };
+          };
+        };
+    };
+  };
+}
diff --git a/nix/host-modules/swarm-nats.nix b/nix/host-modules/swarm-nats.nix
index 34fbaec5..99806e70 100644
--- a/nix/host-modules/swarm-nats.nix
+++ b/nix/host-modules/swarm-nats.nix
@@ -795,6 +795,8 @@ in
                 "--review-classifier-client ${lib.escapeShellArg config.services.hyperhive.swarm.review-classifier.clientId}"
                 # Hears builds and answers each by reply, and nothing else.
                 "--builder-client ${lib.escapeShellArg config.services.hyperhive.swarm.builder.clientId}"
+                # Hears login steps and answers each by reply, and nothing else.
+                "--claude-login-client ${lib.escapeShellArg config.services.hyperhive.swarm.claude-login.clientId}"
                 # What an agent may publish to, keyed on its own name: its
                 # terminal rows and its turn-state header
                 # (`hive-agent::swarm_agent_state`), two subject families so a
diff --git a/nix/host-modules/swarm-required-services.nix b/nix/host-modules/swarm-required-services.nix
index aa5162d0..4e5d0df9 100644
--- a/nix/host-modules/swarm-required-services.nix
+++ b/nix/host-modules/swarm-required-services.nix
@@ -126,4 +126,12 @@ in
     && deployCfg.bao.builderClientCertFile != null
     && deployCfg.bao.builderClientKeyFile != null
   );
+
+  # The claude login minter, defaulted on the same terms as the review
+  # classifier.
+  config.services.hyperhive.deploy.claude-login.enable = lib.mkDefault (
+    deployCfg.allSwarmServices
+    && deployCfg.bao.claudeLoginClientCertFile != null
+    && deployCfg.bao.claudeLoginClientKeyFile != null
+  );
 }
diff --git a/nix/host-modules/swarm-secret-publisher.nix b/nix/host-modules/swarm-secret-publisher.nix
index 49f73446..5c2911be 100644
--- a/nix/host-modules/swarm-secret-publisher.nix
+++ b/nix/host-modules/swarm-secret-publisher.nix
@@ -96,6 +96,8 @@ let
     hyperhiveCfg.swarm.review-classifier.clientId
     # The swarm builder, which reads it itself inside its container.
     hyperhiveCfg.swarm.builder.clientId
+    # The claude login minter, which reads it itself inside its container.
+    hyperhiveCfg.swarm.claude-login.clientId
   ];
 
   # The swarm controller's OIDC client, which it reads back from the store
diff --git a/nix/host-modules/swarm.nix b/nix/host-modules/swarm.nix
index 90ffbdcc..e3fa09df 100644
--- a/nix/host-modules/swarm.nix
+++ b/nix/host-modules/swarm.nix
@@ -59,6 +59,7 @@ let
     deployCfg.bao.metricsAuthCommonName
     deployCfg.bao.reviewClassifierCommonName
     deployCfg.bao.builderCommonName
+    deployCfg.bao.claudeLoginCommonName
     deployCfg.bao.forgePublisherCommonName
   ]
   # The per-hive subjects, spelled out per hive rather than as the prefix.
diff --git a/nix/module-eval/bao-grants.nix b/nix/module-eval/bao-grants.nix
index 47bb5e67..989d2542 100644
--- a/nix/module-eval/bao-grants.nix
+++ b/nix/module-eval/bao-grants.nix
@@ -169,7 +169,7 @@ let
     _: u: (u.environment.BAO_CLIENT_CERT or null) == granterCertFile
   ) baoGrantWithConsumers.systemd.services;
 
-  # The nineteen units that write a `swarm-*` grant, by name, for the discovery
+  # The twenty units that write a `swarm-*` grant, by name, for the discovery
   # control below.
   grantingUnitNames = [
     "swarm-bao-controller-policy"
@@ -191,6 +191,7 @@ let
     "swarm-bao-forge-publisher-policy"
     "swarm-bao-review-classifier-policy"
     "swarm-bao-builder-policy"
+    "swarm-bao-claude-login-policy"
   ];
 
   # Comment lines dropped first: both the HCL and the scripts explain
@@ -976,24 +977,24 @@ let
     }
     {
       # A store host without the granter's pair writes its grants some other
-      # way, so none of the nineteen units may exist. Without this arm
+      # way, so none of the twenty units may exist. Without this arm
       # `lib.mkIf haveGranter` could be dropped from any of them and every other
       # case here would still pass.
-      name = "without the granter's pair none of the nineteen granting units render";
+      name = "without the granter's pair none of the twenty granting units render";
       ok =
         let
           s = baoGranterOptOut.systemd.services;
         in
         lib.all (unit: !(s ? ${unit})) (grantingUnitNames ++ [ "swarm-bao-granter-role" ])
-        # The control: the same store with the pair renders all nineteen.
+        # The control: the same store with the pair renders all twenty.
         && lib.all (unit: baoGrantHere.systemd.services ? ${unit}) grantingUnitNames;
     }
     {
-      # 🩸 What replaced the silent skip. With no bootstrap token the nineteen still
+      # 🩸 What replaced the silent skip. With no bootstrap token the twenty still
       # render, and a refused granter fails them with the step that fixes it.
       # A store host that never named a token is told to name one, since the
       # unit that sets the granter up renders only where it has.
-      name = "a store host without a bootstrap token renders the nineteen, each failing loudly with the one-time step";
+      name = "a store host without a bootstrap token renders the twenty, each failing loudly with the one-time step";
       ok =
         let
           s = baoGranterNoToken.systemd.services;
@@ -1595,6 +1596,44 @@ let
         in
         lib.hasInfix "/builder.pem ]" s && lib.hasInfix "swarm-builder \"\" clientAuth" s;
     }
+    {
+      # The minter writes one leaf under every agent, create and update so a
+      # relogin replaces the last, and reads its own queue client secret. No
+      # read on the leaf, and nothing else under an agent.
+      name = "the claude login minter's grant is create and update on agents' claude-credentials, and its queue client secret";
+      ok =
+        let
+          s = baoGrantHere.systemd.services.swarm-bao-claude-login-policy.script;
+          grants = grantsIn s;
+        in
+        (grantFor grants "secret/data/swarm/agents/+/claude-credentials").caps == [
+          "create"
+          "update"
+        ]
+        && (grantFor grants "secret/data/swarm/services/swarm-claude-login/oidc/client").caps == [ "read" ]
+        && lib.length grants == 2
+        && !(lib.hasInfix "secret/data/swarm/agents/*" s)
+        && lib.hasInfix "auth/cert/certs/swarm-claude-login" s
+        && lib.hasInfix "allowed_common_names=swarm-claude-login" s
+        && lib.hasInfix "token_policies=swarm-claude-login" s;
+    }
+    {
+      # The leaf by name: the minter writes it. The agent's own read and the
+      # controller's `swarm/agents/*` reach it without naming it.
+      name = "no granting unit but the claude login minter's names the claude-credentials leaf";
+      ok =
+        lib.filter (
+          u: lib.hasInfix "claude-credentials" baoGrantHere.systemd.services.${u}.script
+        ) grantingUnitNames == [ "swarm-bao-claude-login-policy" ];
+    }
+    {
+      name = "the PKI unit signs the claude login minter's leaf under its own subject";
+      ok =
+        let
+          s = baoGrantHere.systemd.services.swarm-bao-pki.script;
+        in
+        lib.hasInfix "/claude-login.pem ]" s && lib.hasInfix "swarm-claude-login \"\" clientAuth" s;
+    }
     {
       name = "the PKI unit signs the CI runner's leaf under its own subject";
       ok =
@@ -1826,8 +1865,8 @@ let
     }
     {
       # What makes the case above mean something: discovery by the granter's
-      # certificate reaches all nineteen units, and each yields calls.
-      name = "the granter-policy check sees all nineteen granting units, and parses calls from each";
+      # certificate reaches all twenty units, and each yields calls.
+      name = "the granter-policy check sees all twenty granting units, and parses calls from each";
       ok =
         lib.sort lib.lessThan (lib.attrNames granterUnits) == lib.sort lib.lessThan grantingUnitNames
         && lib.all (u: baoCalls u.script != [ ]) (lib.attrValues granterUnits)
diff --git a/nix/module-eval/core-toggle.nix b/nix/module-eval/core-toggle.nix
index f9fe80bb..0c518ab3 100644
--- a/nix/module-eval/core-toggle.nix
+++ b/nix/module-eval/core-toggle.nix
@@ -365,6 +365,27 @@ let
         && lib.hasInfix socket l."/webhook/forge/".proxyPass
         && !(lib.hasInfix "auth_request" l."/webhook/forge/".extraConfig);
     }
+    {
+      # nginx serves a path from its longest matching prefix location, so that
+      # one must be the gated `/api/`, and no exact location may take a route
+      # out from under it.
+      name = "the claude login routes reach the controller only through a location that asks authelia";
+      ok =
+        let
+          l = allLocal.services.nginx.virtualHosts."t.local".locations;
+          route = "/api/agents/a/claude-login/code";
+          covering = lib.filter (
+            name: !(lib.hasPrefix "~" name) && !(lib.hasPrefix "= " name) && lib.hasPrefix (prefix name) route
+          ) (lib.attrNames l);
+          prefix = lib.removePrefix "^~ ";
+          longest = lib.foldl' (
+            a: b: if lib.stringLength (prefix b) > lib.stringLength (prefix a) then b else a
+          ) "" covering;
+        in
+        longest == "/api/"
+        && lib.hasInfix "auth_request /__hive_authelia;" l.${longest}.extraConfig
+        && !(lib.any (name: lib.hasPrefix "= /api/agents" name) (lib.attrNames l));
+    }
     {
       name = "a hive with matrix off serves no matrix discovery endpoint";
       ok =
diff --git a/nix/module-eval/swarm-services-switch.nix b/nix/module-eval/swarm-services-switch.nix
index b74aab88..d432d9eb 100644
--- a/nix/module-eval/swarm-services-switch.nix
+++ b/nix/module-eval/swarm-services-switch.nix
@@ -163,8 +163,9 @@ let
     lib.filter (l: swarmServiceLinkDomains ? ${l.label}) cfg.services.hyperhive.swarm.controller.links;
 
   # Every service container at once: the services-only host plus the CI
-  # runner. The CI runner, the review classifier, the builder, the metrics
-  # store and the homeserver are the five containers on a netns of their own.
+  # runner. The CI runner, the review classifier, the builder, the claude login
+  # minter, the metrics store and the homeserver are the six containers on a
+  # netns of their own.
   serviceContainersWithCi = hive {
     deploy.hive-controller.enable = false;
     deploy.allSwarmServices = true;
@@ -247,6 +248,30 @@ let
         && !(swarmServicesBaoElsewhere.containers ? swarm-builder)
         && swarmServicesBaoElsewhere.services.hyperhive.deploy.nats.enable;
     }
+    {
+      # Static, not `DynamicUser`: the user is declared in the container and
+      # the unit names it. `nats` is the control that the switch is on at all.
+      name = "hosting the swarm's shared services runs the claude login minter in its container as a static user";
+      ok =
+        let
+          c = swarmServicesHere.containers.swarm-claude-login.config;
+          sc = c.systemd.services.swarm-claude-login.serviceConfig;
+        in
+        swarmServicesHere.services.hyperhive.deploy.claude-login.enable
+        && c.users.users.swarm-claude-login.isSystemUser
+        && sc.User == "swarm-claude-login"
+        && !(sc.DynamicUser or false)
+        && swarmServicesHere.services.hyperhive.deploy.nats.enable;
+    }
+    {
+      # The minter's module asserts the store identity the store's host mints,
+      # as the classifier's does.
+      name = "the claude login minter stays off where the shared services are hosted without the store";
+      ok =
+        !swarmServicesBaoElsewhere.services.hyperhive.deploy.claude-login.enable
+        && !(swarmServicesBaoElsewhere.containers ? swarm-claude-login)
+        && swarmServicesBaoElsewhere.services.hyperhive.deploy.nats.enable;
+    }
     {
       # The switch fills in for an operator who has not spoken and yields to
       # one who has — that is what keeps a shared service placeable on a host
diff --git a/nix/packages/default.nix b/nix/packages/default.nix
index a69602bb..4f764d99 100644
--- a/nix/packages/default.nix
+++ b/nix/packages/default.nix
@@ -182,6 +182,7 @@ in
   # reason: it runs inside its own container, not on the host.
   swarm-review-classifier = mkBinPackage "swarm-review-classifier" "hyperhive review classifier try-out daemon";
   swarm-builder = mkBinPackage "swarm-builder" "hyperhive swarm builder: agent config build checks";
+  swarm-claude-login = mkBinPackage "swarm-claude-login" "hyperhive claude login minter";
 
   # The only process allowed to write swarm-authelia's users database —
   # same "runs *inside* a container, not on the host" placement as
diff --git a/swarm-claude-login/Cargo.toml b/swarm-claude-login/Cargo.toml
new file mode 100644
index 00000000..d2e73949
--- /dev/null
+++ b/swarm-claude-login/Cargo.toml
@@ -0,0 +1,26 @@
+[package]
+name = "swarm-claude-login"
+version.workspace = true
+readme = "README.md"
+edition.workspace = true
+
+[[bin]]
+name = "swarm-claude-login"
+path = "src/main.rs"
+
+[dependencies]
+anyhow.workspace = true
+async-nats.workspace = true
+# StreamExt::next on the subscription.
+futures-util.workspace = true
+hive-log.workspace = true
+serde_json.workspace = true
+# The login subject and the shapes the controller sends and reads back.
+swarm-queue-client.workspace = true
+# The credentials and queue client secret paths, and the store login.
+swarm-secret-client.workspace = true
+tokio.workspace = true
+tracing.workspace = true
+
+[lints]
+workspace = true
diff --git a/swarm-claude-login/README.md b/swarm-claude-login/README.md
new file mode 100644
index 00000000..1d09580f
--- /dev/null
+++ b/swarm-claude-login/README.md
@@ -0,0 +1,20 @@
+# swarm-claude-login
+
+The claude login minter, in the `swarm-claude-login` container on the host
+that sets `deploy.claude-login.enable`. The design is
+[`docs/swarm/claude-login.md`](../docs/swarm/claude-login.md).
+
+swarm-controller relays an operator's login of one agent as two requests on
+`$SWARM.claude-login.request`: a start, answered with the URL
+`claude auth login` printed, and the code the operator pasted, answered once
+the agent's `.credentials.json` is stored at
+`swarm/agents/<agent>/claude-credentials`. Each login runs with `HOME` and
+`CLAUDE_CONFIG_DIR` in its own scratch directory, removed when the login
+ends however it ends.
+
+## Credentials
+
+The container holds one credential: its own store certificate, which nspawn
+hands in at start without a copy on disk. With it the service reads its queue
+client secret, and writes the `claude-credentials` leaf of any agent, a new
+version over the last. Its store role can do exactly those two things.
diff --git a/swarm-claude-login/src/login.rs b/swarm-claude-login/src/login.rs
new file mode 100644
index 00000000..92adca08
--- /dev/null
+++ b/swarm-claude-login/src/login.rs
@@ -0,0 +1,589 @@
+//! One `claude auth login` per agent, driven over plain stdio pipes.
+//!
+//! [`Logins::start`] spawns the login with `HOME` and `CLAUDE_CONFIG_DIR` in
+//! a fresh scratch directory and answers with the first `https://` URL it
+//! prints. [`Logins::code`] writes the operator's code to its stdin, waits
+//! for it to exit, and hands the `.credentials.json` it wrote to a
+//! [`CredentialSink`]. The scratch directory goes with the login, on every
+//! path out: stored, failed, cancelled, replaced or expired.
+
+use std::collections::HashMap;
+use std::future::Future;
+use std::path::{Path, PathBuf};
+use std::process::Stdio;
+use std::sync::Arc;
+use std::time::Duration;
+
+use swarm_queue_client::claude_login::Reply;
+use swarm_secret_client::claude_login::Credentials;
+use tokio::io::{AsyncBufReadExt as _, AsyncRead, AsyncWriteExt as _, BufReader};
+use tokio::process::{Child, ChildStdin, Command};
+use tokio::sync::{Mutex, watch};
+
+/// The file `claude auth login` writes the session to, under its config dir.
+const CREDENTIALS_FILE: &str = ".credentials.json";
+
+/// The most output lines a failure carries back.
+const TAIL_LINES: usize = 20;
+
+/// The variables naming this service's own store identity, kept out of the
+/// login's environment.
+const STRIPPED_ENV: [&str; 4] = [
+    "BAO_ADDR",
+    "BAO_CLIENT_CERT",
+    "BAO_CLIENT_KEY",
+    "BAO_CACERT",
+];
+
+/// Where stored credentials go: the agent's store leaf in production, a map
+/// in the tests.
+pub trait CredentialSink: Send + Sync {
+    /// Store `credentials` as `agent`'s, replacing any stored before.
+    fn put(
+        &self,
+        agent: &str,
+        credentials: &Credentials,
+    ) -> impl Future<Output = anyhow::Result<()>> + Send;
+}
+
+/// The logins running now, one per agent.
+pub struct Logins {
+    claude: PathBuf,
+    scratch_root: PathBuf,
+    step_deadline: Duration,
+    running: Mutex<HashMap<String, Running>>,
+    next_id: std::sync::atomic::AtomicU64,
+}
+
+struct Running {
+    id: u64,
+    session: Session,
+}
+
+/// A spawned `claude auth login` and its scratch directory.
+struct Session {
+    child: Child,
+    stdin: Option<ChildStdin>,
+    output: Arc<std::sync::Mutex<String>>,
+    url: watch::Receiver<Option<String>>,
+    /// The tasks copying stdout and stderr, done at the child's EOF.
+    pumps: Vec<tokio::task::JoinHandle<()>>,
+    scratch: Scratch,
+}
+
+impl Session {
+    /// Wait for the output of an exited child to be copied in full, so a
+    /// failure carries its last lines.
+    async fn settle(&mut self) {
+        for pump in self.pumps.drain(..) {
+            let _ = tokio::time::timeout(Duration::from_secs(2), pump).await;
+        }
+    }
+}
+
+/// A directory removed when dropped.
+struct Scratch(PathBuf);
+
+impl Drop for Scratch {
+    fn drop(&mut self) {
+        if let Err(e) = std::fs::remove_dir_all(&self.0)
+            && e.kind() != std::io::ErrorKind::NotFound
+        {
+            tracing::warn!(dir = %self.0.display(), error = %e, "removing a login's scratch directory failed");
+        }
+    }
+}
+
+impl Logins {
+    /// `claude` is the binary to run; each login's scratch directory is made
+    /// under `scratch_root`.
+    pub fn new(claude: PathBuf, scratch_root: PathBuf, step_deadline: Duration) -> Self {
+        Self {
+            claude,
+            scratch_root,
+            step_deadline,
+            running: Mutex::new(HashMap::new()),
+            next_id: std::sync::atomic::AtomicU64::new(0),
+        }
+    }
+
+    /// Start a login for `agent`, stopping one already running for it, and
+    /// answer with the URL it printed. The login stays running until
+    /// [`Self::code`], [`Self::cancel`] or [`Self::expire`].
+    pub async fn start(&self, agent: &str) -> (Reply, Option<u64>) {
+        let id = self
+            .next_id
+            .fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+        let mut session = match self.spawn(agent, id) {
+            Ok(s) => s,
+            Err(e) => return (failed(&format!("{e:#}"), None), None),
+        };
+        let mut url = session.url.clone();
+        let scraped = tokio::time::timeout(self.step_deadline, async {
+            tokio::select! {
+                found = url.wait_for(Option::is_some) => found.ok().and_then(|u| u.clone()),
+                _ = session.child.wait() => None,
+            }
+        })
+        .await;
+        match scraped {
+            Ok(Some(url)) => {
+                self.running
+                    .lock()
+                    .await
+                    .insert(agent.to_owned(), Running { id, session });
+                (Reply::Started { url }, Some(id))
+            }
+            Ok(None) => {
+                session.settle().await;
+                (
+                    failed(
+                        "claude exited before its login could take a code",
+                        Some(&session),
+                    ),
+                    None,
+                )
+            }
+            Err(_) => (
+                failed(
+                    &format!(
+                        "claude printed no login URL within {}s",
+                        self.step_deadline.as_secs()
+                    ),
+                    Some(&session),
+                ),
+                None,
+            ),
+        }
+    }
+
+    /// Hand `agent`'s running login `code`, and store what it writes.
+    pub async fn code(&self, agent: &str, code: &str, sink: &impl CredentialSink) -> Reply {
+        let Some(Running { mut session, .. }) = self.running.lock().await.remove(agent) else {
+            return failed(
+                &format!("no login is running for {agent}: start one, then paste its code"),
+                None,
+            );
+        };
+        if let Err(e) = submit(&mut session, code).await {
+            return failed(
+                &format!("handing claude the code failed: {e}"),
+                Some(&session),
+            );
+        }
+        let status = match tokio::time::timeout(self.step_deadline, session.child.wait()).await {
+            Ok(Ok(status)) => {
+                session.settle().await;
+                status
+            }
+            Ok(Err(e)) => {
+                return failed(&format!("waiting for claude failed: {e}"), Some(&session));
+            }
+            Err(_) => {
+                return failed(
+                    &format!(
+                        "claude did not finish within {}s of the code",
+                        self.step_deadline.as_secs()
+                    ),
+                    Some(&session),
+                );
+            }
+        };
+        if !status.success() {
+            return failed(&format!("claude {status}"), Some(&session));
+        }
+        let file = config_dir(&session.scratch.0).join(CREDENTIALS_FILE);
+        let value = match tokio::fs::read_to_string(&file).await {
+            Ok(v) if !v.trim().is_empty() => v,
+            Ok(_) => return failed("claude wrote an empty credentials file", Some(&session)),
+            Err(e) => {
+                return failed(
+                    &format!("claude exited without writing its credentials: {e}"),
+                    Some(&session),
+                );
+            }
+        };
+        match sink.put(agent, &Credentials { value }).await {
+            Ok(()) => Reply::Stored,
+            Err(e) => failed(&format!("storing the credentials failed: {e:#}"), None),
+        }
+    }
+
+    /// Stop `agent`'s running login, if any.
+    pub async fn cancel(&self, agent: &str) -> Reply {
+        self.running.lock().await.remove(agent);
+        Reply::Cancelled
+    }
+
+    /// Stop `agent`'s login `id` if it is still the one running: called once
+    /// its time to wait for a code is up.
+    pub async fn expire(&self, agent: &str, id: u64) {
+        let mut running = self.running.lock().await;
+        if running.get(agent).is_some_and(|r| r.id == id) {
+            running.remove(agent);
+            tracing::info!(%agent, "a login waited too long for its code; stopped");
+        }
+    }
+
+    fn spawn(&self, agent: &str, id: u64) -> anyhow::Result<Session> {
+        use anyhow::Context as _;
+        use std::os::unix::fs::DirBuilderExt as _;
+
+        let dir = self.scratch_root.join(format!("{agent}-{id}"));
+        std::fs::DirBuilder::new()
+            .mode(0o700)
+            .create(&dir)
+            .with_context(|| format!("making the scratch directory {}", dir.display()))?;
+        let scratch = Scratch(dir);
+        let mut command = Command::new(&self.claude);
+        command
+            .args(["auth", "login"])
+            .env("HOME", &scratch.0)
+            .env("CLAUDE_CONFIG_DIR", config_dir(&scratch.0))
+            .current_dir(&scratch.0)
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .kill_on_drop(true);
+        for var in STRIPPED_ENV {
+            command.env_remove(var);
+        }
+        let mut child = command
+            .spawn()
+            .with_context(|| format!("spawning {}", self.claude.display()))?;
+        let stdin = child.stdin.take();
+        let output = Arc::new(std::sync::Mutex::new(String::new()));
+        let (url_tx, url) = watch::channel(None);
+        let url_tx = Arc::new(url_tx);
+        let mut pumps = Vec::new();
+        if let Some(out) = child.stdout.take() {
+            pumps.push(tokio::spawn(pump(
+                out,
+                Arc::clone(&output),
+                Arc::clone(&url_tx),
+            )));
+        }
+        if let Some(err) = child.stderr.take() {
+            pumps.push(tokio::spawn(pump(err, Arc::clone(&output), url_tx)));
+        }
+        Ok(Session {
+            child,
+            stdin,
+            output,
+            url,
+            pumps,
+            scratch,
+        })
+    }
+}
+
+/// Where `claude` keeps its config, the credentials among it, under a
+/// login's scratch directory: `$HOME/.claude`, which `CLAUDE_CONFIG_DIR`
+/// names as well.
+fn config_dir(scratch: &Path) -> PathBuf {
+    scratch.join(".claude")
+}
+
+/// Write `code` and a newline to the login's stdin, then close it.
+async fn submit(session: &mut Session, code: &str) -> std::io::Result<()> {
+    let mut stdin = session
+        .stdin
+        .take()
+        .ok_or_else(|| std::io::Error::other("stdin already closed"))?;
+    stdin
+        .write_all(format!("{}\n", code.trim()).as_bytes())
+        .await?;
+    stdin.flush().await
+}
+
+/// Copy one of the child's streams into `output`, and the first URL on it
+/// into `url`.
+async fn pump(
+    stream: impl AsyncRead + Unpin,
+    output: Arc<std::sync::Mutex<String>>,
+    url: Arc<watch::Sender<Option<String>>>,
+) {
+    let mut lines = BufReader::new(stream).lines();
+    while let Ok(Some(line)) = lines.next_line().await {
+        if let Some(found) = extract_url(&line) {
+            url.send_if_modified(|u| {
+                let first = u.is_none();
+                if first {
+                    *u = Some(found);
+                }
+                first
+            });
+        }
+        let mut out = output
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        out.push_str(&line);
+        out.push('\n');
+    }
+}
+
+/// The first `https://…` on `line`, up to whitespace, without trailing
+/// sentence punctuation.
+fn extract_url(line: &str) -> Option<String> {
+    let start = line.find("https://")?;
+    let tail = &line[start..];
+    let end = tail
+        .find(|c: char| c.is_ascii_whitespace())
+        .unwrap_or(tail.len());
+    let url = tail[..end].trim_end_matches(['.', ',', ')', ']']);
+    (url.len() > "https://".len()).then(|| url.to_owned())
+}
+
+fn failed(why: &str, session: Option<&Session>) -> Reply {
+    let tail = session.map(|s| {
+        let out = s
+            .output
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let lines: Vec<&str> = out.lines().collect();
+        lines[lines.len().saturating_sub(TAIL_LINES)..].join("\n")
+    });
+    Reply::Failed {
+        error: match tail {
+            Some(t) if !t.is_empty() => format!("{why}\n{t}"),
+            _ => why.to_owned(),
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::os::unix::fs::PermissionsExt as _;
+
+    use super::*;
+
+    /// A stand-in for `claude auth login`: prints a URL, reads a code, and
+    /// writes a credentials file holding it where `claude` would. A code of
+    /// `bad` exits non-zero without writing; `partial` writes, then exits
+    /// non-zero.
+    const STUB: &str = r#"#!/bin/sh
+[ "$1 $2" = "auth login" ] || { echo "unexpected args: $*" >&2; exit 2; }
+[ "$CLAUDE_CONFIG_DIR" = "$HOME/.claude" ] || { echo "config dir $CLAUDE_CONFIG_DIR" >&2; exit 2; }
+[ -n "$BAO_CLIENT_KEY" ] && { echo "store identity leaked" >&2; exit 2; }
+echo "Opening browser to sign in…"
+echo "If the browser didn't open, visit: https://claude.ai/oauth/authorize?code=true&state=s1."
+printf 'Paste code here if prompted > '
+read code
+if [ "$code" = bad ]; then echo "OAuth error: invalid code" >&2; exit 1; fi
+mkdir -p "$CLAUDE_CONFIG_DIR"
+printf '{"claudeAiOauth":{"accessToken":"%s"}}' "$code" > "$CLAUDE_CONFIG_DIR/.credentials.json"
+if [ "$code" = partial ]; then echo "profile fetch failed" >&2; exit 1; fi
+echo "Login successful."
+"#;
+
+    struct Fixture {
+        root: PathBuf,
+        logins: Logins,
+    }
+
+    impl Drop for Fixture {
+        fn drop(&mut self) {
+            let _ = std::fs::remove_dir_all(&self.root);
+        }
+    }
+
+    /// Every stub, written once before any test spawns one: a file still
+    /// open for writing in a child another test forked meanwhile cannot be
+    /// executed (`ETXTBSY`).
+    fn stubs() -> &'static Path {
+        static DIR: std::sync::OnceLock<PathBuf> = std::sync::OnceLock::new();
+        DIR.get_or_init(|| {
+            let dir = std::env::temp_dir().join(format!(
+                "swarm-claude-login-test-stubs-{}",
+                std::process::id()
+            ));
+            let _ = std::fs::remove_dir_all(&dir);
+            std::fs::create_dir_all(&dir).expect("stub dir");
+            for (name, script) in [
+                ("claude", STUB),
+                ("silent", "#!/bin/sh\nexec sleep 600\n"),
+                ("exits", "#!/bin/sh\necho \"not logged in\" >&2\nexit 1\n"),
+            ] {
+                let stub = dir.join(name);
+                std::fs::write(&stub, script).expect("stub");
+                std::fs::set_permissions(&stub, std::fs::Permissions::from_mode(0o755))
+                    .expect("chmod");
+            }
+            dir
+        })
+    }
+
+    fn fixture(name: &str) -> Fixture {
+        fixture_with(name, "claude", Duration::from_secs(10))
+    }
+
+    fn fixture_with(name: &str, stub: &str, deadline: Duration) -> Fixture {
+        let stub = stubs().join(stub);
+        let root = std::env::temp_dir().join(format!(
+            "swarm-claude-login-test-{name}-{}",
+            std::process::id()
+        ));
+        let _ = std::fs::remove_dir_all(&root);
+        std::fs::create_dir_all(root.join("scratch")).expect("temp dir");
+        let logins = Logins::new(stub, root.join("scratch"), deadline);
+        Fixture { root, logins }
+    }
+
+    fn scratch_dirs(f: &Fixture) -> usize {
+        std::fs::read_dir(f.root.join("scratch"))
+            .expect("scratch root")
+            .count()
+    }
+
+    /// The sink as KV v2 behaves under `write`: every put is a new version
+    /// replacing the last.
+    #[derive(Default)]
+    struct Store(std::sync::Mutex<HashMap<String, (String, u64)>>);
+
+    impl CredentialSink for Store {
+        async fn put(&self, agent: &str, c: &Credentials) -> anyhow::Result<()> {
+            let mut m = self.0.lock().expect("lock");
+            let version = m.get(agent).map_or(1, |(_, v)| v + 1);
+            m.insert(agent.to_owned(), (c.value.clone(), version));
+            Ok(())
+        }
+    }
+
+    impl Store {
+        fn get(&self, agent: &str) -> Option<(String, u64)> {
+            self.0.lock().expect("lock").get(agent).cloned()
+        }
+    }
+
+    #[test]
+    fn the_first_https_url_is_scraped_without_trailing_punctuation() {
+        assert_eq!(
+            extract_url("visit: https://claude.ai/oauth/authorize?code=true&state=s1.").as_deref(),
+            Some("https://claude.ai/oauth/authorize?code=true&state=s1")
+        );
+        assert_eq!(
+            extract_url("(https://a.example/x) or https://b.example").as_deref(),
+            Some("https://a.example/x")
+        );
+        assert_eq!(extract_url("no link here"), None);
+        assert_eq!(extract_url("https:// alone"), None);
+    }
+
+    #[tokio::test]
+    async fn a_login_answers_with_its_url_relays_the_code_and_stores_the_file() {
+        let f = fixture("relay");
+        let store = Store::default();
+        let (reply, _) = f.logins.start("atlas").await;
+        assert_eq!(
+            reply,
+            Reply::Started {
+                url: "https://claude.ai/oauth/authorize?code=true&state=s1".to_owned()
+            }
+        );
+        assert_eq!(scratch_dirs(&f), 1);
+        assert_eq!(
+            f.logins.code("atlas", " c0de \n", &store).await,
+            Reply::Stored
+        );
+        assert_eq!(
+            store.get("atlas"),
+            Some((r#"{"claudeAiOauth":{"accessToken":"c0de"}}"#.to_owned(), 1))
+        );
+        assert_eq!(
+            scratch_dirs(&f),
+            0,
+            "the scratch directory outlived the store write"
+        );
+    }
+
+    #[tokio::test]
+    async fn a_relogin_overwrites_the_stored_credentials() {
+        let f = fixture("overwrite");
+        let store = Store::default();
+        for code in ["first", "second"] {
+            f.logins.start("atlas").await;
+            assert_eq!(f.logins.code("atlas", code, &store).await, Reply::Stored);
+        }
+        assert_eq!(
+            store.get("atlas"),
+            Some((
+                r#"{"claudeAiOauth":{"accessToken":"second"}}"#.to_owned(),
+                2
+            ))
+        );
+    }
+
+    #[tokio::test]
+    async fn a_refused_code_stores_nothing_and_says_what_claude_printed() {
+        let f = fixture("refused");
+        let store = Store::default();
+        f.logins.start("atlas").await;
+        let Reply::Failed { error } = f.logins.code("atlas", "bad", &store).await else {
+            panic!("a refused code was not a failure");
+        };
+        assert!(error.contains("invalid code"), "{error}");
+        assert_eq!(store.get("atlas"), None);
+        assert_eq!(scratch_dirs(&f), 0);
+    }
+
+    #[tokio::test]
+    async fn a_login_that_exits_non_zero_stores_nothing_even_with_a_file() {
+        let f = fixture("partial");
+        let store = Store::default();
+        f.logins.start("atlas").await;
+        assert!(matches!(
+            f.logins.code("atlas", "partial", &store).await,
+            Reply::Failed { .. }
+        ));
+        assert_eq!(store.get("atlas"), None);
+    }
+
+    #[tokio::test]
+    async fn a_code_with_no_login_running_is_refused() {
+        let f = fixture("none");
+        let store = Store::default();
+        assert!(matches!(
+            f.logins.code("atlas", "c", &store).await,
+            Reply::Failed { .. }
+        ));
+        // The control: the same code after a start is taken.
+        f.logins.start("atlas").await;
+        assert_eq!(f.logins.code("atlas", "c", &store).await, Reply::Stored);
+    }
+
+    #[tokio::test]
+    async fn a_restart_replaces_the_running_login_and_its_scratch() {
+        let f = fixture("restart");
+        f.logins.start("atlas").await;
+        f.logins.start("atlas").await;
+        assert_eq!(scratch_dirs(&f), 1);
+        assert_eq!(f.logins.cancel("atlas").await, Reply::Cancelled);
+        assert_eq!(scratch_dirs(&f), 0);
+    }
+
+    #[tokio::test]
+    async fn an_expiry_stops_only_the_login_it_was_set_for() {
+        let f = fixture("expire");
+        let (_, first) = f.logins.start("atlas").await;
+        let (_, second) = f.logins.start("atlas").await;
+        f.logins.expire("atlas", first.expect("started")).await;
+        assert_eq!(
+            scratch_dirs(&f),
+            1,
+            "a stale expiry stopped the newer login"
+        );
+        f.logins.expire("atlas", second.expect("started")).await;
+        assert_eq!(scratch_dirs(&f), 0);
+    }
+
+    #[tokio::test]
+    async fn a_login_that_prints_no_url_fails_its_start_and_leaves_no_scratch() {
+        for name in ["silent", "exits"] {
+            let f = fixture_with(name, name, Duration::from_millis(500));
+            let (reply, id) = f.logins.start("atlas").await;
+            assert!(matches!(reply, Reply::Failed { .. }), "{name}: {reply:?}");
+            assert_eq!(id, None, "{name}");
+            assert_eq!(scratch_dirs(&f), 0, "{name}");
+        }
+    }
+}
diff --git a/swarm-claude-login/src/main.rs b/swarm-claude-login/src/main.rs
new file mode 100644
index 00000000..99af5729
--- /dev/null
+++ b/swarm-claude-login/src/main.rs
@@ -0,0 +1,192 @@
+//! The claude login minter.
+//!
+//! Connects to the swarm queue as its own OIDC client, takes an operator's
+//! login steps from swarm-controller on
+//! [`swarm_queue_client::claude_login::SUBJECT`], runs `claude auth login`
+//! for the agent named ([`login`]), and writes the credentials it produces to
+//! that agent's store leaf, a new version over any stored before. The agent's
+//! harness takes a version newer than the one it last installed.
+//!
+//! The store identity comes from the `BAO_*` environment. The queue client
+//! secret is read at start and again when authelia refuses it; the store is
+//! logged in to afresh for each write.
+
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::time::Duration;
+
+use anyhow::{Context, Result, bail};
+use futures_util::StreamExt as _;
+use swarm_queue_client::claude_login::{Reply, Request, SESSION_DEADLINE, STEP_DEADLINE, SUBJECT};
+use swarm_queue_client::stored_secret::StoredSecret;
+use swarm_queue_client::{ClientSecret, QueueConfig};
+use swarm_secret_client::claude_login::{Credentials, client_secret_path, credentials_path};
+
+mod login;
+
+/// The cert-auth role this service logs in to the store as. `swarm-bao.nix`
+/// writes it, matching the leaf's subject.
+const CERT_ROLE: &str = "swarm-claude-login";
+
+/// The environment prefix `swarm-claude-login.nix` sets.
+const PREFIX: &str = "SWARM_CLAUDE_LOGIN";
+
+/// Seconds to wait after each failed read of the queue client secret. A
+/// longer outage fails the start, and the unit's `Restart=` tries again.
+const RETRY_DELAYS_S: [u64; 6] = [1, 2, 4, 8, 16, 30];
+
+/// The agent's store leaf, written under this service's certificate.
+struct AgentLeaf;
+
+impl login::CredentialSink for AgentLeaf {
+    async fn put(&self, agent: &str, credentials: &Credentials) -> Result<()> {
+        let path = credentials_path(agent)?;
+        let store = swarm_secret_client::SecretStore::from_env(CERT_ROLE)
+            .await
+            .context("logging in to the secret store")?;
+        // `write`, not `create`: a relogin replaces what an earlier one
+        // stored.
+        store
+            .write(&path, credentials)
+            .await
+            .with_context(|| format!("writing {path}"))
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    hive_log::init();
+    swarm_queue_client::install_crypto_provider();
+    let var = |name: &str| {
+        let full = format!("{PREFIX}_{name}");
+        std::env::var(&full).with_context(|| format!("{full} is unset"))
+    };
+    let client_id = var("OIDC_CLIENT_ID")?;
+    let logins = Arc::new(login::Logins::new(
+        PathBuf::from(var("CLAUDE")?),
+        std::env::temp_dir(),
+        STEP_DEADLINE,
+    ));
+    let secret = client_secret_with_retry(&client_id).await?;
+    let reread_id = client_id.clone();
+    let secret = StoredSecret::new(client_id.clone(), secret, move || {
+        let client_id = reread_id.clone();
+        async move { client_secret(&client_id).await.map_err(Into::into) }
+    });
+    let queue = swarm_queue_client::connect(QueueConfig {
+        url: var("NATS_URL")?,
+        token_endpoint: var("OIDC_TOKEN_ENDPOINT")?,
+        client_id,
+        client_secret: ClientSecret::Stored(secret),
+        ca_file: std::env::var(format!("{PREFIX}_OIDC_CA_FILE"))
+            .ok()
+            .map(PathBuf::from),
+    })
+    .await?;
+    // No queue group: a running login lives in this process's memory, so
+    // every step for it has to reach this process.
+    let mut requests = queue
+        .subscribe(SUBJECT)
+        .await
+        .with_context(|| format!("subscribing to {SUBJECT}"))?;
+    tracing::info!(subject = SUBJECT, "claude login minter: awaiting logins");
+
+    while let Some(msg) = requests.next().await {
+        let Some(reply_to) = msg.reply.clone() else {
+            tracing::warn!("a login step arrived with no reply subject; dropping it");
+            continue;
+        };
+        let queue = queue.clone();
+        let logins = Arc::clone(&logins);
+        tokio::spawn(async move {
+            let reply = handle(&msg.payload, &logins).await;
+            match serde_json::to_vec(&reply) {
+                Ok(body) => {
+                    if let Err(e) = queue.publish(reply_to, body.into()).await {
+                        tracing::warn!(error = %e, "publishing a login step's reply failed");
+                    }
+                }
+                Err(e) => tracing::warn!(error = %e, "encoding a login step's reply failed"),
+            }
+        });
+    }
+    bail!("the subscription to {SUBJECT} ended")
+}
+
+/// Decode one step, run it and log it. Never logs the code or the URL.
+async fn handle(payload: &[u8], logins: &Arc<login::Logins>) -> Reply {
+    let request: Request = match serde_json::from_slice(payload) {
+        Ok(r) => r,
+        Err(e) => {
+            tracing::warn!(error = %e, "an undecodable login step; answering with the error");
+            return Reply::Failed {
+                error: format!("the minter could not decode the request: {e}"),
+            };
+        }
+    };
+    let (agent, reply) = match request {
+        Request::Start { agent, operator } => {
+            tracing::info!(%agent, %operator, "starting a claude login");
+            let (reply, id) = logins.start(&agent).await;
+            if let Some(id) = id {
+                let logins = Arc::clone(logins);
+                let expiring = agent.clone();
+                tokio::spawn(async move {
+                    tokio::time::sleep(SESSION_DEADLINE).await;
+                    logins.expire(&expiring, id).await;
+                });
+            }
+            (agent, reply)
+        }
+        Request::Code { agent, code } => {
+            let reply = logins.code(&agent, &code, &AgentLeaf).await;
+            (agent, reply)
+        }
+        Request::Cancel { agent } => {
+            let reply = logins.cancel(&agent).await;
+            (agent, reply)
+        }
+    };
+    match &reply {
+        Reply::Started { .. } => tracing::info!(%agent, "claude login waiting for its code"),
+        Reply::Stored => tracing::info!(%agent, "claude credentials stored"),
+        Reply::Cancelled => tracing::info!(%agent, "claude login cancelled"),
+        Reply::Failed { error } => tracing::warn!(%agent, %error, "claude login step failed"),
+    }
+    reply
+}
+
+/// The queue client secret, read from the store, retried through a store that
+/// is restarting alongside this service.
+async fn client_secret_with_retry(client_id: &str) -> Result<String> {
+    for delay in RETRY_DELAYS_S.map(Duration::from_secs) {
+        match client_secret(client_id).await {
+            Ok(secret) => return Ok(secret),
+            Err(e) => {
+                tracing::warn!(error = %format!("{e:#}"), retry_in = ?delay, "reading the queue client secret failed");
+                tokio::time::sleep(delay).await;
+            }
+        }
+    }
+    client_secret(client_id).await
+}
+
+async fn client_secret(client_id: &str) -> Result<String> {
+    use swarm_secret_client::builder::ClientSecret;
+
+    let path = client_secret_path(client_id)?;
+    let store = swarm_secret_client::SecretStore::from_env(CERT_ROLE)
+        .await
+        .context("logging in to the secret store")?;
+    let stored: Option<ClientSecret> = store
+        .read_optional(&path)
+        .await
+        .with_context(|| format!("reading {path}"))?;
+    match stored {
+        Some(s) if !s.value.trim().is_empty() => Ok(s.value.trim().to_owned()),
+        _ => bail!(
+            "nothing at {path}: swarm-secret-publish, on the host that runs authelia, has not \
+             published this service's client secret"
+        ),
+    }
+}
diff --git a/swarm-controller/src/claude_login.rs b/swarm-controller/src/claude_login.rs
new file mode 100644
index 00000000..10425785
--- /dev/null
+++ b/swarm-controller/src/claude_login.rs
@@ -0,0 +1,313 @@
+//! An agent's claude login, run from the swarm UI: the operator's two steps,
+//! relayed to the `swarm-claude-login` minter over the queue.
+//!
+//! - `POST /api/agents/{name}/claude-login` starts `claude auth login` for
+//!   the agent and answers with the URL to open.
+//! - `POST /api/agents/{name}/claude-login/code` hands it the code that page
+//!   shows; the minter stores the credentials at
+//!   `swarm/agents/<agent>/claude-credentials` and the agent's harness
+//!   installs them.
+//! - `DELETE /api/agents/{name}/claude-login` stops a login started and not
+//!   finished.
+//!
+//! The operator is the `Remote-User` header the gateway sets, as for
+//! [`crate::agent_input`]. Nothing here touches the store: the minter holds
+//! the one grant that writes the credentials.
+
+use std::future::Future;
+
+use axum::Json;
+use axum::extract::{Path, State};
+use axum::http::{HeaderMap, StatusCode};
+use problem_details::ProblemDetails;
+use serde::{Deserialize, Serialize};
+use swarm_queue_client::claude_login::{REPLY_DEADLINE, Reply, Request, SUBJECT};
+use utoipa::ToSchema;
+
+use crate::{AppState, error_problem};
+
+/// The header the gateway names the session's user in.
+const OPERATOR_HEADER: &str = "remote-user";
+
+/// Where a step is sent: the queue in production, a fake in the tests.
+/// `Err` is a step that never reached the minter or never came back.
+pub(crate) trait LoginSink {
+    fn step(&self, request: Vec<u8>) -> impl Future<Output = Result<Reply, String>> + Send;
+}
+
+impl LoginSink for async_nats::Client {
+    async fn step(&self, request: Vec<u8>) -> Result<Reply, String> {
+        use async_nats::RequestErrorKind;
+
+        let sent = async_nats::Request::new()
+            .payload(request.into())
+            .timeout(Some(REPLY_DEADLINE));
+        match self.send_request(SUBJECT, sent).await {
+            Ok(msg) => serde_json::from_slice(&msg.payload)
+                .map_err(|e| format!("the claude login minter's reply did not decode: {e}")),
+            Err(e) => Err(match e.kind() {
+                RequestErrorKind::NoResponders => "no claude login minter is listening: \
+                     deploy.claude-login.enable is set on no host, or its service is not \
+                     connected to the swarm queue"
+                    .to_owned(),
+                RequestErrorKind::TimedOut => format!(
+                    "the claude login minter sent no answer within {}s",
+                    REPLY_DEADLINE.as_secs()
+                ),
+                _ => format!("sending the step to the claude login minter failed: {e}"),
+            }),
+        }
+    }
+}
+
+/// The page the operator opens to log the agent in.
+#[derive(Serialize, ToSchema)]
+pub struct ClaudeLoginStarted {
+    pub url: String,
+}
+
+/// The code the login page showed. No `Debug`: it is a one-time credential.
+#[derive(Deserialize, ToSchema)]
+pub struct PostClaudeLoginCodeRequest {
+    /// Not logged.
+    code: String,
+}
+
+/// Start a claude login for an agent.
+#[utoipa::path(
+    post,
+    path = "/api/agents/{name}/claude-login",
+    params(("name" = String, Path, description = "agent to log in")),
+    responses(
+        (status = 200, description = "the login is running; open `url` and post the code it shows", body = ClaudeLoginStarted),
+        (status = 400, description = "the agent name is not an identifier (problem+json)", body = String),
+        (status = 401, description = "the request carries no `Remote-User` (problem+json)", body = String),
+        (status = 502, description = "the minter could not start the login (problem+json)", body = String),
+        (status = 503, description = "no swarm queue here, or no minter listening on it (problem+json)", body = String),
+    ),
+    tag = "agents"
+)]
+pub(crate) async fn post_claude_login(
+    State(state): State<AppState>,
+    Path(agent): Path<String>,
+    headers: HeaderMap,
+) -> Result<Json<ClaudeLoginStarted>, ProblemDetails> {
+    let operator = operator(&headers).map_err(problem)?;
+    let agent = agent_name(&agent).map_err(problem)?;
+    let sink = queue(&state).map_err(problem)?;
+    match relay(&sink, &Request::Start { agent, operator }).await? {
+        Reply::Started { url } => Ok(Json(ClaudeLoginStarted { url })),
+        other => Err(unexpected(&other)),
+    }
+}
+
+/// Hand an agent's running claude login the code its page showed.
+#[utoipa::path(
+    post,
+    path = "/api/agents/{name}/claude-login/code",
+    params(("name" = String, Path, description = "agent being logged in")),
+    request_body = PostClaudeLoginCodeRequest,
+    responses(
+        (status = 204, description = "the credentials are stored; the agent installs them within a minute"),
+        (status = 400, description = "the agent name is not an identifier, or the code is empty (problem+json)", body = String),
+        (status = 401, description = "the request carries no `Remote-User` (problem+json)", body = String),
+        (status = 502, description = "the login failed or its credentials could not be stored (problem+json)", body = String),
+        (status = 503, description = "no swarm queue here, or no minter listening on it (problem+json)", body = String),
+    ),
+    tag = "agents"
+)]
+pub(crate) async fn post_claude_login_code(
+    State(state): State<AppState>,
+    Path(agent): Path<String>,
+    headers: HeaderMap,
+    Json(req): Json<PostClaudeLoginCodeRequest>,
+) -> Result<StatusCode, ProblemDetails> {
+    let operator = operator(&headers).map_err(problem)?;
+    let agent = agent_name(&agent).map_err(problem)?;
+    let code = req.code.trim();
+    if code.is_empty() {
+        return Err(error_problem(StatusCode::BAD_REQUEST, "code is empty"));
+    }
+    let sink = queue(&state).map_err(problem)?;
+    let request = Request::Code {
+        agent: agent.clone(),
+        code: code.to_owned(),
+    };
+    match relay(&sink, &request).await? {
+        Reply::Stored => {
+            tracing::info!(%agent, %operator, "claude credentials stored for the agent");
+            Ok(StatusCode::NO_CONTENT)
+        }
+        other => Err(unexpected(&other)),
+    }
+}
+
+/// Stop an agent's running claude login.
+#[utoipa::path(
+    delete,
+    path = "/api/agents/{name}/claude-login",
+    params(("name" = String, Path, description = "agent being logged in")),
+    responses(
+        (status = 204, description = "no login is running for the agent now"),
+        (status = 400, description = "the agent name is not an identifier (problem+json)", body = String),
+        (status = 401, description = "the request carries no `Remote-User` (problem+json)", body = String),
+        (status = 503, description = "no swarm queue here, or no minter listening on it (problem+json)", body = String),
+    ),
+    tag = "agents"
+)]
+pub(crate) async fn delete_claude_login(
+    State(state): State<AppState>,
+    Path(agent): Path<String>,
+    headers: HeaderMap,
+) -> Result<StatusCode, ProblemDetails> {
+    operator(&headers).map_err(problem)?;
+    let agent = agent_name(&agent).map_err(problem)?;
+    let sink = queue(&state).map_err(problem)?;
+    match relay(&sink, &Request::Cancel { agent }).await? {
+        Reply::Cancelled => Ok(StatusCode::NO_CONTENT),
+        other => Err(unexpected(&other)),
+    }
+}
+
+/// A refusal decided before the queue is touched.
+type Refusal = (StatusCode, String);
+
+fn problem((status, detail): Refusal) -> ProblemDetails {
+    error_problem(status, &detail)
+}
+
+fn operator(headers: &HeaderMap) -> Result<String, Refusal> {
+    headers
+        .get(OPERATOR_HEADER)
+        .and_then(|v| v.to_str().ok())
+        .map(str::trim)
+        .filter(|s| !s.is_empty())
+        .map(str::to_owned)
+        .ok_or_else(|| {
+            (
+                StatusCode::UNAUTHORIZED,
+                "no Remote-User header: the gateway names the operator, and this request did \
+                 not come through it"
+                    .to_owned(),
+            )
+        })
+}
+
+fn agent_name(agent: &str) -> Result<String, Refusal> {
+    Ok(hive_types::Ident::parse(agent)
+        .map_err(|reason| (StatusCode::BAD_REQUEST, reason.to_owned()))?
+        .into_string())
+}
+
+fn queue(state: &AppState) -> Result<async_nats::Client, Refusal> {
+    let Some(status) = state.status.as_ref() else {
+        return Err((
+            StatusCode::SERVICE_UNAVAILABLE,
+            "no swarm queue is configured on this host".to_owned(),
+        ));
+    };
+    let client = status.queue_client();
+    swarm_queue_client::ensure_connected(&client).map_err(|e| {
+        (
+            StatusCode::SERVICE_UNAVAILABLE,
+            swarm_queue_client::chain(&e),
+        )
+    })?;
+    Ok(client)
+}
+
+/// Send `request` and return the minter's reply, a `Failed` one as a 502.
+async fn relay(sink: &impl LoginSink, request: &Request) -> Result<Reply, ProblemDetails> {
+    let payload = serde_json::to_vec(request).map_err(|e| {
+        error_problem(
+            StatusCode::INTERNAL_SERVER_ERROR,
+            &format!("encoding the step failed: {e}"),
+        )
+    })?;
+    match sink.step(payload).await {
+        Ok(Reply::Failed { error }) => Err(error_problem(StatusCode::BAD_GATEWAY, &error)),
+        Ok(reply) => Ok(reply),
+        Err(e) => Err(error_problem(StatusCode::SERVICE_UNAVAILABLE, &e)),
+    }
+}
+
+fn unexpected(reply: &Reply) -> ProblemDetails {
+    error_problem(
+        StatusCode::BAD_GATEWAY,
+        &format!("the claude login minter answered out of step: {reply:?}"),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Mutex;
+
+    use axum::http::StatusCode;
+    use swarm_queue_client::claude_login::{Reply, Request};
+
+    use super::{LoginSink, relay};
+
+    /// Answers every step with one fixed outcome and records what it got.
+    struct FakeSink {
+        answer: Result<Reply, String>,
+        got: Mutex<Vec<Vec<u8>>>,
+    }
+
+    impl LoginSink for FakeSink {
+        async fn step(&self, request: Vec<u8>) -> Result<Reply, String> {
+            self.got.lock().expect("lock").push(request);
+            self.answer.clone()
+        }
+    }
+
+    fn sink(answer: Result<Reply, String>) -> FakeSink {
+        FakeSink {
+            answer,
+            got: Mutex::default(),
+        }
+    }
+
+    #[tokio::test]
+    async fn the_code_reaches_the_minter_as_sent() {
+        let s = sink(Ok(Reply::Stored));
+        let request = Request::Code {
+            agent: "atlas".to_owned(),
+            code: "Abc_9.x-Q".to_owned(),
+        };
+        assert!(matches!(relay(&s, &request).await, Ok(Reply::Stored)));
+        let got: serde_json::Value =
+            serde_json::from_slice(&s.got.lock().expect("lock")[0]).expect("json");
+        assert_eq!(got["step"], "code");
+        assert_eq!(got["agent"], "atlas");
+        assert_eq!(got["code"], "Abc_9.x-Q");
+    }
+
+    #[tokio::test]
+    async fn a_failed_step_is_a_bad_gateway_naming_why() {
+        let s = sink(Ok(Reply::Failed {
+            error: "OAuth error: invalid code".to_owned(),
+        }));
+        let request = Request::Cancel {
+            agent: "atlas".to_owned(),
+        };
+        let e = relay(&s, &request).await.expect_err("a failure");
+        assert_eq!(e.status, Some(StatusCode::BAD_GATEWAY));
+        assert!(
+            e.detail
+                .as_deref()
+                .is_some_and(|d| d.contains("invalid code")),
+            "{:?}",
+            e.detail
+        );
+    }
+
+    #[tokio::test]
+    async fn an_unreached_minter_is_unavailable() {
+        let s = sink(Err("no claude login minter is listening".to_owned()));
+        let request = Request::Cancel {
+            agent: "atlas".to_owned(),
+        };
+        let e = relay(&s, &request).await.expect_err("unreached");
+        assert_eq!(e.status, Some(StatusCode::SERVICE_UNAVAILABLE));
+    }
+}
diff --git a/swarm-controller/src/main.rs b/swarm-controller/src/main.rs
index 9f628bae..201f6af7 100644
--- a/swarm-controller/src/main.rs
+++ b/swarm-controller/src/main.rs
@@ -52,6 +52,7 @@ mod agent_state_stream;
 mod agent_status;
 mod auth;
 mod builder;
+mod claude_login;
 mod config_pr;
 mod forge;
 mod forge_account;
@@ -3426,6 +3427,11 @@ fn build_app(state: AppState) -> axum::Router {
         .routes(routes!(agent_state_stream::stream_agent_state))
         .routes(routes!(agent_input::post_agent_input))
         .routes(routes!(agent_control::post_agent_cancel))
+        .routes(routes!(
+            claude_login::post_claude_login,
+            claude_login::delete_claude_login
+        ))
+        .routes(routes!(claude_login::post_claude_login_code))
         .routes(routes!(schedules::list_schedules, schedules::add_schedule))
         .routes(routes!(
             schedules::edit_schedule,
diff --git a/swarm-nats-auth/src/main.rs b/swarm-nats-auth/src/main.rs
index 8ef55f85..98d0f728 100644
--- a/swarm-nats-auth/src/main.rs
+++ b/swarm-nats-auth/src/main.rs
@@ -167,6 +167,11 @@ struct Args {
     #[arg(long = "builder-client")]
     builder_clients: Vec<String>,
 
+    /// Client ids that answer the claude login minter's login requests.
+    /// Repeatable, empty by default, which denies such a client.
+    #[arg(long = "claude-login-client")]
+    claude_login_clients: Vec<String>,
+
     /// Role on the secret store's `cert` auth mount this responder logs in
     /// as to read the callout keys, its own OIDC client secret and agent
     /// credentials. The store is found
@@ -232,7 +237,8 @@ async fn serve(args: &Args) -> anyhow::Result<()> {
     )?
     .with_agent_token_subjects(args.agent_token_publish_subjects.clone())?
     .with_review_classifiers(args.review_classifier_clients.clone())
-    .with_builders(args.builder_clients.clone());
+    .with_builders(args.builder_clients.clone())
+    .with_claude_logins(args.claude_login_clients.clone());
     let http = reqwest::Client::new();
     let settings = swarm_secret_client::client::Settings::from_env()
         .context("reading the secret store's address and this responder's identity")?;
diff --git a/swarm-nats-auth/src/policy.rs b/swarm-nats-auth/src/policy.rs
index dc3c6e31..94463a40 100644
--- a/swarm-nats-auth/src/policy.rs
+++ b/swarm-nats-auth/src/policy.rs
@@ -51,6 +51,7 @@ pub struct Policy {
     agent_token_subjects: Vec<String>,
     review_classifiers: Vec<String>,
     builders: Vec<String>,
+    claude_logins: Vec<String>,
 }
 
 /// Placeholder replaced with the hive's own name in `extra_hive_subjects`.
@@ -122,6 +123,7 @@ impl Policy {
             agent_token_subjects: Vec::new(),
             review_classifiers: Vec::new(),
             builders: Vec::new(),
+            claude_logins: Vec::new(),
         })
     }
 
@@ -157,6 +159,13 @@ impl Policy {
         self
     }
 
+    /// Set the client ids that answer the claude login minter's requests.
+    #[must_use]
+    pub fn with_claude_logins(mut self, clients: Vec<String>) -> Self {
+        self.claude_logins = clients;
+        self
+    }
+
     /// The permissions for an agent whose own credential was verified, or
     /// `None` when none are configured.
     ///
@@ -229,6 +238,9 @@ impl Policy {
         if self.builders.iter().any(|c| c == client_id) {
             return Some(Self::builder_permissions(client_id));
         }
+        if self.claude_logins.iter().any(|c| c == client_id) {
+            return Some(Self::claude_login_permissions(client_id));
+        }
         None
     }
 
@@ -263,6 +275,20 @@ impl Policy {
         }
     }
 
+    /// What the claude login minter may do: hear login steps and answer each
+    /// on its reply subject. Its publish list is its own inbox, for
+    /// [`Self::review_classifier_permissions`]' reason.
+    fn claude_login_permissions(client_id: &str) -> Permissions {
+        Permissions {
+            publish: vec![Self::inbox(client_id)],
+            subscribe: Some(vec![
+                swarm_queue_client::claude_login::SUBJECT.to_owned(),
+                Self::inbox(client_id),
+            ]),
+            responses: Some(swarm_queue_client::claude_login::REPLY_DEADLINE),
+        }
+    }
+
     /// What a hive may subscribe to: the two events the controller sends it,
     /// and its own reply inbox.
     ///
@@ -603,6 +629,8 @@ impl Policy {
             swarm_queue_client::review_classifier::SUBJECT.to_owned(),
             // A build of an agent config, sent as a request the same way.
             swarm_queue_client::builder::SUBJECT.to_owned(),
+            // An operator's claude login step, sent as a request the same way.
+            swarm_queue_client::claude_login::SUBJECT.to_owned(),
             // The wanted-state buckets — one per hive, all created and written
             // by this single client.
             //
@@ -1402,6 +1430,63 @@ mod tests {
         }
     }
 
+    const CLAUDE_LOGIN: &str = "swarm-claude-login";
+
+    #[test]
+    fn the_claude_login_minter_hears_its_subject_and_inbox_only_and_answers_by_reply() {
+        use swarm_queue_client::claude_login::{REPLY_DEADLINE, SUBJECT};
+        use swarm_queue_client::client_inbox_prefix;
+
+        let p = policy()
+            .with_claude_logins(vec![CLAUDE_LOGIN.to_owned()])
+            .permissions(CLAUDE_LOGIN)
+            .expect("a configured minter is admitted");
+        let inbox = client_inbox_prefix(CLAUDE_LOGIN);
+        assert!(may_subscribe(&p, SUBJECT));
+        assert!(may_subscribe(&p, &reply(&inbox)));
+        for refused in [
+            ">".to_owned(),
+            "$SWARM.>".to_owned(),
+            swarm_queue_client::builder::SUBJECT.to_owned(),
+            reply(&client_inbox_prefix("swarm-controller")),
+        ] {
+            assert!(
+                !may_subscribe(&p, &refused),
+                "the minter may subscribe to {refused}"
+            );
+        }
+        assert_eq!(p.publish, vec![format!("{inbox}.>")]);
+        assert_eq!(p.responses, Some(REPLY_DEADLINE));
+        // The minter's id is nothing until it is configured.
+        assert_eq!(policy().permissions(CLAUDE_LOGIN), None);
+    }
+
+    #[test]
+    fn only_the_reader_may_send_a_login_step() {
+        use swarm_queue_client::claude_login::SUBJECT;
+
+        let p = with_classifier()
+            .with_builders(vec![BUILDER.to_owned()])
+            .with_claude_logins(vec![CLAUDE_LOGIN.to_owned()]);
+        let reader = p.permissions("swarm-controller").expect("the reader");
+        assert!(reader.publish.iter().any(|g| covers(g, SUBJECT)));
+        for (who, grant) in [
+            ("a hive", p.permissions("hive-alpha").expect("a hive")),
+            ("the minter", p.permissions(CLAUDE_LOGIN).expect("admitted")),
+            ("the builder", p.permissions(BUILDER).expect("admitted")),
+            (
+                "the classifier",
+                p.permissions(CLASSIFIER).expect("admitted"),
+            ),
+        ] {
+            assert!(
+                !grant.publish.iter().any(|g| covers(g, SUBJECT)),
+                "{who} may send a login step: {:?}",
+                grant.publish
+            );
+        }
+    }
+
     #[test]
     fn the_prefix_alone_names_no_hive() {
         // `hive-` would otherwise produce `$KV.hive-status.`, a subject nobody
diff --git a/swarm-queue-client/src/claude_login.rs b/swarm-queue-client/src/claude_login.rs
new file mode 100644
index 00000000..d1242cec
--- /dev/null
+++ b/swarm-queue-client/src/claude_login.rs
@@ -0,0 +1,93 @@
+//! The claude login minter's requests: the subject swarm-controller sends an
+//! operator's login steps on, and what travels each way.
+//!
+//! Three crates name these: the controller sends the requests, the minter
+//! answers them, and the auth-callout responder grants the one subject to
+//! each.
+//!
+//! A login is two requests for one agent:
+//! [`Request::Start`](crate::claude_login::Request::Start) runs
+//! `claude auth login` and answers with the URL it printed, and
+//! [`Request::Code`](crate::claude_login::Request::Code) hands it the code the
+//! operator pasted and answers once the credentials are in the agent's store
+//! leaf. The running login lives in the minter's memory between the two, so
+//! the swarm runs one minter.
+
+use std::time::Duration;
+
+use serde::{Deserialize, Serialize};
+
+/// The subject every request goes to. The controller is its one publisher
+/// and the minter its one subscriber; the minter answers on the request's
+/// reply subject.
+pub const SUBJECT: &str = "$SWARM.claude-login.request";
+
+/// The longest the minter waits for `claude` to print the login URL, and
+/// then for it to finish once the code is in.
+pub const STEP_DEADLINE: Duration = Duration::from_mins(1);
+
+/// How long the controller waits for a reply, and the queue lets the minter
+/// answer: a step at its deadline, plus the store write.
+pub const REPLY_DEADLINE: Duration = Duration::from_secs(90);
+
+/// How long a started login waits for its code before the minter stops it
+/// and deletes its scratch directory.
+pub const SESSION_DEADLINE: Duration = Duration::from_mins(15);
+
+/// One step of an operator's login of one agent.
+///
+/// No `Debug` derive: [`Request::Code`] carries the one-time code.
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(tag = "step", rename_all = "kebab-case")]
+pub enum Request {
+    /// Start a login for `agent`, replacing one already running for it.
+    Start {
+        agent: String,
+        /// The swarm UI user, as the gateway named them.
+        operator: String,
+    },
+    /// Hand the running login for `agent` the code the operator pasted.
+    Code { agent: String, code: String },
+    /// Stop the running login for `agent`, if any.
+    Cancel { agent: String },
+}
+
+/// The minter's answer to one [`Request`].
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(tag = "state", rename_all = "kebab-case")]
+pub enum Reply {
+    /// The login is running; the operator opens `url` and pastes the code it
+    /// shows back.
+    Started { url: String },
+    /// The credentials are stored in the agent's leaf, as its newest
+    /// version.
+    Stored,
+    /// The running login, if there was one, is stopped.
+    Cancelled,
+    /// The step failed: why, with the last lines `claude` printed where it
+    /// printed any.
+    Failed { error: String },
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn the_wire_tags_the_request_by_step_and_the_reply_by_state() {
+        let json = serde_json::to_value(Request::Code {
+            agent: "atlas".to_owned(),
+            code: "c".to_owned(),
+        })
+        .expect("encodes");
+        assert_eq!(json["step"], "code");
+        assert_eq!(json["agent"], "atlas");
+        let json = serde_json::to_value(Reply::Stored).expect("encodes");
+        assert_eq!(json["state"], "stored");
+    }
+
+    #[test]
+    fn the_reply_deadline_outlasts_a_step() {
+        assert!(REPLY_DEADLINE > STEP_DEADLINE);
+    }
+}
diff --git a/swarm-queue-client/src/lib.rs b/swarm-queue-client/src/lib.rs
index 9dce4ec2..b2b31dc2 100644
--- a/swarm-queue-client/src/lib.rs
+++ b/swarm-queue-client/src/lib.rs
@@ -462,6 +462,10 @@ pub mod stored_secret;
 /// The builder's build subject and the request and reply it carries.
 pub mod builder;
 
+/// The claude login minter's subject and the requests and replies it
+/// carries.
+pub mod claude_login;
+
 /// Only the fields this needs; authelia returns several.
 #[derive(serde::Deserialize)]
 struct TokenResponse {
diff --git a/swarm-secret-client/Cargo.toml b/swarm-secret-client/Cargo.toml
index eed8fe9e..05b5cf9b 100644
--- a/swarm-secret-client/Cargo.toml
+++ b/swarm-secret-client/Cargo.toml
@@ -13,12 +13,12 @@ reqwest.workspace = true
 rustify.workspace = true
 rustify_derive.workspace = true
 serde.workspace = true
+# `read_versioned` decodes the data half of the response vaultrs hands back as
+# a `serde_json::Value`.
+serde_json.workspace = true
 strum.workspace = true
 thiserror.workspace = true
 vaultrs.workspace = true
 
-[dev-dependencies]
-serde_json.workspace = true
-
 [lints]
 workspace = true
diff --git a/swarm-secret-client/src/claude_login.rs b/swarm-secret-client/src/claude_login.rs
new file mode 100644
index 00000000..782822fa
--- /dev/null
+++ b/swarm-secret-client/src/claude_login.rs
@@ -0,0 +1,108 @@
+//! The claude login agreement: where an agent's claude credentials live in
+//! the store, what the object there holds, and where the minter's own queue
+//! client secret lives.
+//!
+//! The `swarm-claude-login` minter writes [`credentials_path`] under its own
+//! certificate, a new version on every login, and `hive-agent` reads it back
+//! under the agent's. Its write stanza in `swarm-bao.nix` names exactly this
+//! leaf under every agent.
+
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    Error,
+    path::{Kind, principal_prefix},
+};
+
+/// The path holding `agent`'s claude credentials.
+///
+/// A flat leaf under the agent's prefix, like
+/// [`crate::github::account_path`], so the agent's own read stanza
+/// ([`crate::policy::render_agent`]) already covers it.
+///
+/// # Errors
+/// [`Error::PathSegment`] when `agent` contains anything but `[A-Za-z0-9_-]`,
+/// which is what keeps one agent's name from addressing another agent's secret.
+pub fn credentials_path(agent: &str) -> Result<String, Error> {
+    let prefix = principal_prefix(Kind::Agent, agent)?;
+    Ok(format!("{prefix}/claude-credentials"))
+}
+
+/// What a [`credentials_path`] holds.
+///
+/// No `Debug` derive: `value` is a live claude session.
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Credentials {
+    /// The `.credentials.json` `claude auth login` wrote, byte for byte.
+    pub value: String,
+}
+
+impl std::fmt::Debug for Credentials {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Credentials")
+            .field("value", &"<redacted>")
+            .finish()
+    }
+}
+
+/// The path holding the queue client secret of the minter's OIDC client
+/// `client_id`, where `swarm-secret-publisher.nix` puts every swarm service's.
+///
+/// # Errors
+/// [`Error::PathSegment`] when `client_id` is not a single path segment.
+pub fn client_secret_path(client_id: &str) -> Result<String, Error> {
+    crate::builder::client_secret_path(client_id)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn covered_by(policy: &str, path: &str) -> bool {
+        policy.lines().any(|line| {
+            line.strip_prefix("path \"")
+                .and_then(|rest| rest.split_once("\" {"))
+                .and_then(|(p, _)| p.strip_suffix('*'))
+                .is_some_and(|prefix| format!("secret/data/{path}").starts_with(prefix))
+        })
+    }
+
+    #[test]
+    fn the_credentials_land_under_the_agent_prefix() {
+        // Spelled out: `swarm-bao.nix`'s minter stanza spells the same leaf.
+        assert_eq!(
+            credentials_path("atlas").expect("a plain name is legal"),
+            "swarm/agents/atlas/claude-credentials"
+        );
+    }
+
+    #[test]
+    fn a_traversal_in_the_agent_name_is_refused() {
+        for bad in ["../argus", "a/b", "a.b", ""] {
+            let e = credentials_path(bad).expect_err("a traversal is not legal");
+            assert!(matches!(e, Error::PathSegment { kind: "agent", .. }), "{e}");
+        }
+        assert!(credentials_path("a-b_C9").is_ok());
+    }
+
+    #[test]
+    fn the_agents_own_read_grant_covers_the_path() {
+        let path = credentials_path("atlas").expect("legal");
+        let own = crate::policy::render_agent("atlas").expect("legal");
+        assert!(
+            covered_by(&own, &path),
+            "no stanza in\n{own}\ncovers {path}"
+        );
+        let other = crate::policy::render_agent("argus").expect("legal");
+        assert!(!covered_by(&other, &path), "argus's policy reaches {path}");
+    }
+
+    #[test]
+    fn debug_never_prints_the_value() {
+        let c = Credentials {
+            value: "0123456789abcdef".to_owned(),
+        };
+        let shown = format!("{c:?}");
+        assert!(!shown.contains("0123456789abcdef"), "{shown}");
+    }
+}
diff --git a/swarm-secret-client/src/client.rs b/swarm-secret-client/src/client.rs
index f7394e3b..ef4125f3 100644
--- a/swarm-secret-client/src/client.rs
+++ b/swarm-secret-client/src/client.rs
@@ -218,6 +218,34 @@ impl SecretStore {
         }
     }
 
+    /// The newest version of the object at `path` and its KV v2 version
+    /// number, or `None` when nothing is stored there.
+    ///
+    /// One read, so the number is the one the value was stored as. Every
+    /// [`write`][Self::write] makes a larger one.
+    ///
+    /// # Errors
+    /// As [`read_optional`][Self::read_optional].
+    pub async fn read_versioned<T: DeserializeOwned>(
+        &self,
+        path: &str,
+    ) -> Result<Option<(T, u64)>, Error> {
+        let endpoint = vaultrs::api::kv2::requests::ReadSecretRequest::builder()
+            .mount(MOUNT)
+            .path(path)
+            .build()
+            .map_err(|e| Error::Settings(e.to_string()))?;
+        match vaultrs::api::exec_with_result(&self.inner, endpoint).await {
+            Ok(res) => {
+                let value = serde_json::from_value(res.data)
+                    .map_err(|source| vaultrs::error::ClientError::JsonParseError { source })?;
+                Ok(Some((value, res.metadata.version)))
+            }
+            Err(vaultrs::error::ClientError::APIError { code: 404, .. }) => Ok(None),
+            Err(e) => Err(e.into()),
+        }
+    }
+
     /// The keys stored directly under `path`, or none when nothing is.
     ///
     /// A key ending in `/` is a directory below `path` rather than an object;
diff --git a/swarm-secret-client/src/lib.rs b/swarm-secret-client/src/lib.rs
index eeb4e78b..229dda4b 100644
--- a/swarm-secret-client/src/lib.rs
+++ b/swarm-secret-client/src/lib.rs
@@ -6,8 +6,9 @@
 //! deployment's environment into a logged-in client ([`client`]), and, per kind
 //! of secret, the path it lives at together with the fields it holds
 //! ([`matrix`], [`queue`], [`mtls`], [`forge`], [`github`], [`acp`], [`ci`],
-//! [`review_classifier`], [`builder`]). Each of those is a thing the controller
-//! and a hive must say identically, so it is said once here.
+//! [`review_classifier`], [`builder`], [`claude_login`]). Each of those is a
+//! thing the controller and a hive must say identically, so it is said once
+//! here.
 //!
 //! [`policy`] is the same kind of agreement seen from the other side: which of
 //! those paths a given principal's own token may read — a hive's, and an
@@ -26,6 +27,7 @@
 pub mod acp;
 pub mod builder;
 pub mod ci;
+pub mod claude_login;
 pub mod client;
 pub mod forge;
 pub mod github;