diff --git a/docs/observability.md b/docs/observability.md
index 4b23a4bb..a1f16a7c 100644
--- a/docs/observability.md
+++ b/docs/observability.md
@@ -186,6 +186,31 @@ redefines it — the agent-facing value is *derived*
 keeps working unchanged. The bridge port is contributed to `exposeHostPorts`
 automatically; there is nothing to open by hand.
 
+### Authenticated ingest
+
+The swarm tier gives **each hive its own receiver**, and stamps the `hive` label
+from whichever receiver accepted a sample. A hive therefore cannot report
+metrics as another hive, and cannot relabel its own by editing what it sends —
+the label is not taken from the payload at all.
+
+**On an all-local swarm there is nothing to set.** Each hive already has an
+identity, and its collector reads the secret that host's own authelia minted.
+
+**On a hive that does not host the swarm's services**, the secret has to arrive
+somehow — copy it across and name it:
+
+```nix
+services.hyperhive.otel.clientSecretFile = "/run/secrets/hive-telemetry.secret";
+```
+
+**There is no unauthenticated mode.** A hive always presents an identity, so a
+missing credential is a build error rather than a quieter fallback — the
+collector has no anonymous route to accept samples on, and every path it serves
+belongs to exactly one hive.
+
+Getting the secret wrong shows up as the hive's collector logging 401s from the
+swarm tier and no metrics appearing for that hive.
+
 ### `services.hyperhive.otel.collector.port` — port, default `4318`
 
 The OTLP/HTTP port the hive tier listens on, bound to the bridge IP only. The
diff --git a/docs/setup.md b/docs/setup.md
index d5ec447c..cdebe400 100644
--- a/docs/setup.md
+++ b/docs/setup.md
@@ -156,6 +156,11 @@ See [`tools/hivectl.md`](tools/hivectl.md) for every `hivectl` verb.
 - All config changes (forge PRs on `agent-configs/<name>`) go through
   operator approval — agents can't unilaterally rebuild containers, by design.
   See [`boundary.md`](boundary.md) and [`security.md`](security.md).
+- **Telemetry ingest is authenticated per hive**, and the `hive` label comes
+  from which hive authenticated rather than from the payload — so no hive can
+  report metrics as another. A first-run all-local hive gets this with nothing
+  to configure; joining a swarm you don't host needs one secret copied across.
+  See [`observability.md`](observability.md#authenticated-ingest).
 
 Once the hive is running, ruth records anything it needs to remember
 across restarts in `/agents/ruth/state/notes.md`.
diff --git a/docs/swarm/secrets.md b/docs/swarm/secrets.md
index 23547b7c..4d324944 100644
--- a/docs/swarm/secrets.md
+++ b/docs/swarm/secrets.md
@@ -45,7 +45,7 @@ Every row below is read against one of these.
 | authelia session, JWT and storage-encryption keys | authelia's first-boot unit, in-container | `/var/lib/authelia-swarm/{session,jwt,storage-encryption}.key` | generated in place; nothing outside that container reads them |
 | authelia OIDC HMAC key | same unit | `/var/lib/authelia-swarm/oidc-hmac.key` | same |
 | authelia OIDC issuer key (RSA) | same unit | `/var/lib/authelia-swarm/oidc-issuer.key` | same — relying parties verify against the **public** half at `/jwks.json` |
-| OIDC client secret, plaintext half | `authelia crypto hash generate --random` | `/var/lib/authelia-swarm/oidc-clients/<id>.secret` | operator provides the file and names it in the service's `sso.clientSecretFile` |
+| OIDC client secret, plaintext half | `authelia crypto hash generate --random` | `/var/lib/authelia-swarm/oidc-clients/<id>.secret` | operator provides the file and names it in whichever option reads it — `sso.clientSecretFile` for a service, `otel.clientSecretFile` for the hive's telemetry collector |
 | OIDC client secret, digest half | the same mint | `oidc-clients/<id>.digest` | authelia's own half; merged at runtime via `settingsFiles` |
 | authelia subject store | `swarmctl` and `swarm-authelia-bridge` | `users.yml` — one file, read and written by both | `swarmctl`, on the host that runs authelia |
 | wireguard private key | **the operator** — `wg genkey` | whatever `swarm.wireguard.privateKeyFile` names | always operator-provided; nothing generates this for you |
@@ -56,6 +56,13 @@ because nothing outside that container ever reads them. **That is the test worth
 applying to any secret added here** — and the client secret's plaintext half is
 the one row that fails it, which is the entire reason a delivery step exists.
 
+One reader needs no delivery step: the **hive's telemetry collector**, which
+authenticates to the swarm's collector as its own hive. It is a host unit rather
+than a container, so on an all-local swarm it reads authelia's file where it
+lies (through `LoadCredential`) and no second copy is made. On any other
+topology it is an ordinary "operator provides the file" case — see
+`services.hyperhive.otel.clientSecretFile`.
+
 ### Minting the queue's callout nkeys
 
 `nats.autoGenerateCallout` mints both keypairs on the host before the queue
diff --git a/nix/host-modules/lib/hive-ca-trust.nix b/nix/host-modules/lib/hive-ca-trust.nix
index 509730c3..0ad563ea 100644
--- a/nix/host-modules/lib/hive-ca-trust.nix
+++ b/nix/host-modules/lib/hive-ca-trust.nix
@@ -39,10 +39,26 @@ let
   # the bundle next to the CA and explains the split.
   caHostPath = "${tlsCfg.stateDir}/trust-bundle.pem";
   caContainerPath = "/run/hive-ca/trust-bundle.pem";
+
+  # One definition, used by `trustBundle` to WRITE the bundle and published
+  # below so a caller can NAME it. Two copies of this path would be two
+  # things to keep in step, and the one that drifts is the reader.
+  bundleDirFor = name: "/run/${name}-ca";
+  bundlePathFor = name: "${bundleDirFor name}/trust-bundle.pem";
 in
 {
   inherit useSelfSigned caContainerPath;
 
+  # Where `trustBundle` below puts the assembled bundle, for the callers
+  # that must NAME it rather than just have it exported. `SSL_CERT_FILE` is
+  # set for you and needs no path here; a consumer that takes its own CA
+  # argument (an OIDC verifier's `issuer_ca_path`, a client's `--cacert`)
+  # does, and the alternative is copying `/run/<name>-ca/…` to the call
+  # site. That copy breaks silently: the bundle keeps being written, the
+  # consumer keeps reading a path that no longer exists, and the failure
+  # surfaces as a TLS error naming the peer rather than the file.
+  inherit bundlePathFor;
+
   # Fold into the container's `bindMounts` via `//`. Binds ONLY the public
   # CA cert (never the `hive-tls` state dir — it holds the CA + leaf private
   # keys), read-only. Empty when not self-signed, so the whole trust path
@@ -106,8 +122,8 @@ in
       enable ? true,
     }:
     let
-      dir = "/run/${name}-ca";
-      bundlePath = "${dir}/trust-bundle.pem";
+      dir = bundleDirFor name;
+      bundlePath = bundlePathFor name;
       unit = "${name}-ca-bundle";
       source = if hostUnit then caHostPath else caContainerPath;
     in
diff --git a/nix/host-modules/otel.nix b/nix/host-modules/otel.nix
index 53d43329..2800717c 100644
--- a/nix/host-modules/otel.nix
+++ b/nix/host-modules/otel.nix
@@ -193,6 +193,40 @@ in
       '';
     };
 
+    clientSecretFile = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      default =
+        if
+          config.services.hyperhive.swarm.authelia.enable && config.services.hyperhive.hiveName != null
+        then
+          "${config.services.hyperhive.swarm.authelia.hostClientSecretDir}/"
+          + "${config.services.hyperhive.swarm.authelia.hiveClientPrefix}${config.services.hyperhive.hiveName}.secret"
+        else
+          null;
+      defaultText = lib.literalExpression ''"''${swarm.authelia.hostClientSecretDir}/''${swarm.authelia.hiveClientPrefix}''${hiveName}.secret" when this host runs the swarm's IdP, else null'';
+      example = "/var/lib/secrets/hive-telemetry.secret";
+      description = ''
+        Absolute path to this hive's OAuth2 client secret, used to
+        authenticate to the swarm's collector as this hive.
+
+        **Whether this is set is what decides whether this tier
+        authenticates at all.** A credential is the only thing that makes
+        authenticated egress possible, so its presence is the condition
+        rather than a second switch that could disagree with it.
+
+        Defaults to the secret this host's own authelia minted, which is
+        correct exactly when the swarm's IdP runs here. On a hive that is
+        not that host, the file has to arrive some other way and this
+        option names wherever it landed — the same manual-copy shape
+        `services.hyperhive.swarm.authelia.oidc.hiveIdentities` documents,
+        where delivering a secret to a hive that is not this host is
+        deliberately not solved.
+
+        Read by `LoadCredential`, so it is never evaluated by nix, never
+        copied into the store and never passed in argv.
+      '';
+    };
+
     metricIntervalMs = lib.mkOption {
       type = lib.types.nullOr lib.types.ints.positive;
       default = null;
@@ -214,8 +248,32 @@ in
   config = lib.mkIf config.services.hyperhive.otel.enable (
     let
       otel = config.services.hyperhive.otel;
+      autheliaCfg = config.services.hyperhive.swarm.authelia;
+      swarmOtelCfg = config.services.hyperhive.swarm.otel;
+      hiveName = config.services.hyperhive.hiveName;
       listen = "${config.services.hyperhive.network.bridgeIp}:${toString otel.collector.port}";
       swarmName = "otlphttp/swarm";
+      authName = "oauth2client/swarm";
+
+      # A hive always authenticates to the swarm's collector as itself, so
+      # this is not a mode — it is a precondition, and the assertion below
+      # is what enforces it. Kept as a name because several places have to
+      # read "do we have what it takes", and an eval error from a null path
+      # names this file rather than the option an operator has to set.
+      senderAuth = otel.clientSecretFile != null && hiveName != null;
+
+      # This hive's client id, and also the audience it must ASK for. Both
+      # are `hiveClientPrefix` + the hive's name because that is the one
+      # name the swarm already agrees on; the receiver one tier up derives
+      # the same string.
+      hiveClient = "${autheliaCfg.hiveClientPrefix}${toString hiveName}";
+
+      # systemd exports `CREDENTIALS_DIRECTORY` to any unit with
+      # `LoadCredential`, and the collector expands `${env:…}` at load. So
+      # the secret reaches the process as a PATH resolved at runtime — nix
+      # renders neither the value nor the directory, and nothing has to
+      # hardcode `/run/credentials/<unit>`.
+      credName = "swarm-client.secret";
     in
     {
       # Reachable from agent containers and nowhere else: this opens
@@ -224,6 +282,22 @@ in
 
       services.opentelemetry-collector = {
         enable = true;
+        # Contrib, matching the swarm tier (./swarm-otel.nix). The upstream
+        # default build has no auth extensions at all, and this tier has to
+        # *present* a credential to the swarm tier — `oauth2client` lives
+        # only in contrib, so the package choice is what makes authenticated
+        # egress expressible rather than a preference.
+        #
+        # Not a build-farm cost: contrib is fetched, not compiled.
+        #
+        # ⚠️ Read the note directly below before adding any extension here.
+        # It describes precisely the trap this package unlocks: naming an
+        # extension the build lacks passes `validate` and then kills the
+        # collector at startup. With contrib the extensions exist — but the
+        # gap it warns about (a green build proving nothing about whether
+        # the process starts) is exactly why this module's auth wiring is
+        # gated by a probe that runs both collectors, not by eval.
+        package = pkgs.opentelemetry-collector-contrib;
         # `validateConfigFile` defaults to `isStorePath configFile`,
         # and `configFile` is null on the `settings` path — so the
         # upstream default is OFF for exactly the way this module
@@ -263,15 +337,80 @@ in
             # change. `https://` because that name resolves through the
             # gateway even on a co-located host — see `caTrust` above for
             # the trust half that makes this verify.
-            endpoint = "https://${config.services.hyperhive.swarm.otel.domain}";
-          };
+            # The hive's own path under the collector's single name. The
+            # swarm tier gives each hive its own authenticated receiver and
+            # routes to it by this prefix, so the path is not decoration —
+            # it selects WHICH receiver, and therefore which hive the
+            # samples get labelled as.
+            endpoint = "https://${swarmOtelCfg.domain}" + lib.optionalString senderAuth "/${toString hiveName}";
+          }
+          // lib.optionalAttrs senderAuth { auth.authenticator = authName; };
+
+          # ⚠️ An extension not listed here is INERT: the collector starts
+          # clean and the exporter naming it sends nothing authenticated.
+          service.extensions = lib.optional senderAuth authName;
 
           service.pipelines.metrics = {
             receivers = [ "otlp" ];
             exporters = [ swarmName ];
           };
+        }
+        // lib.optionalAttrs senderAuth {
+          extensions.${authName} = {
+            client_id = hiveClient;
+            # A real key, measured against this collector version rather
+            # than assumed — with a deliberate typo rejected in the same
+            # run, so "accepted" is distinguishable from "ignores
+            # everything". Keeps the secret out of nix entirely: the
+            # collector opens the file itself.
+            client_secret_file = "\${env:CREDENTIALS_DIRECTORY}/${credName}";
+            token_url = "${toString autheliaCfg.url}/api/oidc/token";
+            # ⚠️ THE AUDIENCE HAS TO BE REQUESTED, not merely granted.
+            # Registering it on the client only makes it permissible; a
+            # token minted without asking carries `aud: []` and every
+            # receiver refuses it — with a config that reads perfectly at
+            # both ends. Measured against authelia 4.39.20.
+            endpoint_params.audience = hiveClient;
+          };
         };
       };
+
+      # `LoadCredential` and not a copy-oneshot: this collector is a HOST
+      # unit, so there is no container boundary to cross and therefore no
+      # reason for a second on-disk copy of the secret. systemd hands it to
+      # the process in a private tmpfs and exports the directory, which is
+      # what the config above names.
+      systemd.services.opentelemetry-collector.serviceConfig = lib.optionalAttrs senderAuth {
+        LoadCredential = [ "${credName}:${otel.clientSecretFile}" ];
+      };
+
+      assertions = [
+        {
+          # A hive authenticates to the swarm's collector as itself — there
+          # is no unauthenticated path to fall back to, so a missing
+          # credential is a broken deployment rather than a quieter mode.
+          # Caught here because the alternative is a collector that starts
+          # cleanly, retries forever, and reports nothing to anyone.
+          assertion = senderAuth;
+          message = ''
+            services.hyperhive.otel.enable is true but this hive has no
+            identity to present to the swarm's collector:
+
+              services.hyperhive.otel.clientSecretFile = ${
+                if otel.clientSecretFile == null then "null" else otel.clientSecretFile
+              }
+              services.hyperhive.hiveName             = ${if hiveName == null then "null" else hiveName}
+
+            Every hive authenticates as itself — that is what makes the
+            `hive` label on its metrics mean anything — so both are
+            required.
+
+            On a host that runs the swarm's identity provider, the default
+            already points at the secret authelia minted. On a hive that
+            does not, copy that hive's secret across and name it here.
+          '';
+        }
+      ];
     }
   );
 }
diff --git a/nix/host-modules/swarm-authelia.nix b/nix/host-modules/swarm-authelia.nix
index c25cf13a..6a419cf4 100644
--- a/nix/host-modules/swarm-authelia.nix
+++ b/nix/host-modules/swarm-authelia.nix
@@ -102,11 +102,26 @@ let
   # and a field later added to the submodule then existed on the
   # declared entries and not on these, which is an eval error reachable
   # only once hive identities are on.
+  #
+  # `audience` is the hive's own client id rather than a second per-hive
+  # string invented here. A swarm service that has to tell hives apart
+  # needs one name per hive that both sides already agree on, and the
+  # client id is that name — published as `hiveClientPrefix` for exactly
+  # this reason. Minting a parallel naming scheme would be a second thing
+  # to keep in step, and the one that drifts is the one nobody tests.
+  #
+  # `RS256` because a resource server that cannot call this provider back
+  # is a real case here: the swarm's telemetry collector verifies tokens
+  # offline against `/jwks.json`, and an opaque token gives it nothing to
+  # verify. The queue's auth-callout responder introspects instead, which
+  # is a different question asked of the same token.
   hiveClients = lib.mapAttrsToList (name: _: {
     id = "${cfg.hiveClientPrefix}${name}";
     description = "HyperHive hive ${name}";
     kind = "machine";
     redirectUris = [ ];
+    audience = [ "${cfg.hiveClientPrefix}${name}" ];
+    accessTokenSignedResponseAlg = "RS256";
   }) hyperhiveCfg.swarm.hives;
 
   # `swarm-authelia-bridge`'s own identity — distinct from
@@ -188,6 +203,15 @@ let
     + lib.optionalString (c.tokenEndpointAuthMethod != null) ''
       printf -- '        token_endpoint_auth_method: %s\n' ${lib.escapeShellArg c.tokenEndpointAuthMethod}
     ''
+    # Flow-style YAML, matching `scopes` below. The values are client ids
+    # and hive names, which `Ident` already constrains to `[a-z0-9-]` — no
+    # character in that set needs quoting in a YAML flow sequence.
+    + lib.optionalString (c.audience != [ ]) ''
+      printf -- '        audience: [%s]\n' ${lib.escapeShellArg (lib.concatStringsSep ", " c.audience)}
+    ''
+    + lib.optionalString (c.accessTokenSignedResponseAlg != null) ''
+      printf -- '        access_token_signed_response_alg: %s\n' ${lib.escapeShellArg c.accessTokenSignedResponseAlg}
+    ''
     + (
       if c.kind == "machine" then
         ''
@@ -493,6 +517,63 @@ in
                 the secret is at fault.
               '';
             };
+
+            audience = lib.mkOption {
+              type = lib.types.listOf lib.types.str;
+              default = [ ];
+              example = [ "hive-alpha" ];
+              description = ''
+                Audiences (`aud`) this client is permitted to request a
+                token for. Empty means it asks for none, which is the
+                right answer for a client whose resource server does not
+                distinguish callers.
+
+                ⚠️ Registering an audience only *permits* it — the value
+                lands in a token when the client **asks** for it at the
+                token endpoint, and a client that does not send
+                `audience=` receives a token with `aud: []` however
+                complete this list looks. Measured against authelia
+                4.39.20: the config reads exactly right and the resource
+                server rejects every token, because a config that grants
+                and a request that claims are two separate acts.
+
+                Requesting an audience that is *not* listed here is
+                refused with `invalid_target`, which is what makes this
+                usable as a boundary rather than a label: a client cannot
+                mint a token for a resource slot that is not its own.
+              '';
+            };
+
+            accessTokenSignedResponseAlg = lib.mkOption {
+              type = lib.types.nullOr (
+                lib.types.enum [
+                  "none"
+                  "RS256"
+                ]
+              );
+              default = null;
+              example = "RS256";
+              description = ''
+                Signing algorithm for this client's **access** tokens.
+                `null` leaves authelia on its default, which issues an
+                opaque token (`authelia_at_…`) — a database handle that
+                carries no claims and means nothing to anyone but this
+                provider.
+
+                Set `RS256` when the resource server verifies the token
+                *itself* rather than asking this provider about it: that
+                yields an RFC 9068 JWT (`at+jwt`) carrying `aud`, `iss`
+                and `client_id`, verifiable against `/jwks.json` with no
+                round trip.
+
+                ⚠️ This is what makes a token readable by an
+                OIDC-verifying consumer at all. A resource server given
+                an opaque token is not *misconfigured* — it is
+                structurally unable to verify it, and says so in terms
+                that point at the verifier rather than at the token's
+                format.
+              '';
+            };
           };
         }
       );
diff --git a/nix/host-modules/swarm-otel.nix b/nix/host-modules/swarm-otel.nix
index 0eacc0de..525bac27 100644
--- a/nix/host-modules/swarm-otel.nix
+++ b/nix/host-modules/swarm-otel.nix
@@ -40,6 +40,43 @@ let
   # the required-domain assertion in hive-network.nix should be what an
   # operator sees, not a coercion error from here.
   domainBase = if swarmDomain == null then "invalid" else swarmDomain;
+
+  autheliaCfg = hyperhiveCfg.swarm.authelia;
+
+  # `attrNames` is sorted, so this is a function of the hive SET and not of
+  # the order anyone wrote it in.
+  #
+  # These ports are internal and appear in no URL: a hive addresses its own
+  # receiver as a PATH on this collector's single gateway name, and nginx —
+  # rendered from this same evaluation — is the only thing that ever names
+  # the port. That is what makes deriving them safe here and unsafe in the
+  # obvious other place: were a hive told a port, inserting a hive would
+  # renumber the ones after it and silently move a port a running hive was
+  # already sending to.
+  hivePorts = lib.listToAttrs (
+    lib.imap0 (i: h: lib.nameValuePair h (cfg.port + i)) (lib.attrNames hyperhiveCfg.swarm.hives)
+  );
+
+  # The swarm's authelia is reached by its gateway name, whose leaf is
+  # issued by the swarm services sub-CA — so this container needs the same
+  # runtime CA trust every other consumer of a swarm-service name needs.
+  # The CA is generated at runtime and cannot be baked into a derivation,
+  # which is why it arrives as a bind mount rather than
+  # `security.pki.certificateFiles`.
+  caTrust = import ./lib/hive-ca-trust.nix {
+    inherit lib;
+    tlsCfg = hyperhiveCfg.tls;
+    inherit gatewayCfg;
+  };
+  caBundle = caTrust.bundlePathFor cfg.machine;
+
+  # One list, read by every pipeline: the per-hive pipelines fan out to
+  # exactly the same destinations as the single pipeline they replace.
+  # Written once because "which exporters" is a property of this tier, not
+  # of which hive a sample came from.
+  exporterNames =
+    lib.optional (otelCfg.endpoint != "") (if otelCfg.protocol == "grpc" then "otlp" else "otlphttp")
+    ++ lib.optional vmCfg.enable "otlphttp/victoriametrics";
 in
 {
   options.services.hyperhive.swarm.otel = {
@@ -75,7 +112,17 @@ in
       type = lib.types.port;
       default = 4319;
       description = ''
-        Port this collector's OTLP/HTTP receiver listens on.
+        First port of this collector's receiver range. Every hive in
+        {option}`services.hyperhive.swarm.hives` gets its **own**
+        authenticated receiver — that is what makes the `hive` label
+        unforgeable — so the range is one port per hive, starting here, in
+        sorted-name order.
+
+        ⚠️ Internal. No client is ever told a port: a hive reaches its own
+        receiver as `https://''${domain}/<hive>`, and the gateway routes on
+        that path. So adding a hive, which renumbers the ones after it, is
+        harmless — nginx is rendered from this same evaluation and moves
+        with it.
 
         ⚠️ **Deliberately not 4318**, the OTLP/HTTP default, because the
         hive tier already uses it (`services.hyperhive.otel.collector.port`)
@@ -83,7 +130,9 @@ in
         listeners claiming one port on one host is not a build failure —
         it is a runtime coin toss over which one gets it, with nothing in
         any log saying so. The same collision cost a release when grafana
-        and the forge both defaulted to 3000.
+        and the forge both defaulted to 3000. The assertions below check
+        the whole derived range against every port this module and the hive
+        tier declare, which is as far as a module can see.
       '';
     };
 
@@ -143,11 +192,39 @@ in
     services.nginx.virtualHosts."${cfg.domain}" = (gatewayCfg.lib.tlsFor cfg.domain) // {
       listen = gatewayCfg.lib.listen;
       extraConfig = gatewayCfg.lib.securityHeaders;
-      locations."/" = {
-        proxyPass = "http://127.0.0.1:${toString cfg.port}";
-      };
+      locations =
+        # One name for the whole collector, and the hive is a path under
+        # it. The alternative — a vhost per hive — needs a certificate,
+        # a DNS name and a `localNames` entry per hive to express the
+        # same routing the gateway already does for free.
+        #
+        # ⚠️ The trailing slash on both sides is load-bearing: it is what
+        # strips `/<hive>` before the request reaches the receiver, which
+        # serves `/v1/metrics` and knows nothing about hives. Without it
+        # the receiver sees `/<hive>/v1/metrics` and answers 404 to a
+        # request that authenticated perfectly.
+        lib.mapAttrs' (
+          h: p: lib.nameValuePair "/${h}/" { proxyPass = "http://127.0.0.1:${toString p}/"; }
+        ) hivePorts
+        // {
+          # There is no swarm-wide inbox, and a closed door is the honest
+          # description of that. Every route into this collector belongs to
+          # exactly one hive.
+          "/".return = "404";
+        };
     };
 
+    # Turning on the identities this tier authenticates against, which the
+    # option exists to allow: its own description names this module as the
+    # second consumer, so the queue is not a prerequisite for authenticated
+    # telemetry.
+    services.hyperhive.swarm.authelia.oidc.hiveIdentities = true;
+
+    # The CA bind source is written at runtime by a host unit, so the
+    # container has to start after it — otherwise nspawn sets up a mount
+    # over a file that does not exist yet.
+    systemd.services."container@${cfg.machine}" = caTrust.containerOrdering;
+
     assertions = [
       {
         # The tier exists to hold the upstream credential and to write the
@@ -164,6 +241,67 @@ in
           metrics store.
         '';
       }
+      {
+        # Without a roster there are no receivers at all, so this
+        # collector would listen on nothing while looking configured.
+        assertion = hyperhiveCfg.swarm.hives != { };
+        message = ''
+          services.hyperhive.swarm.otel.enable is true but
+          services.hyperhive.swarm.hives is empty: ingest is authenticated
+          per hive, so an empty roster means this collector accepts nothing
+          from anyone.
+
+          List the swarm's hives.
+        '';
+      }
+      {
+        # A hive proves who it is with a token this provider mints, so
+        # there is no version of this collector that runs without one.
+        # Stated as an assertion rather than a fallback because a guessed
+        # issuer URL evaluates cleanly and refuses every hive at runtime.
+        assertion = autheliaCfg.url != null;
+        message = ''
+          services.hyperhive.swarm.otel.enable is true but
+          services.hyperhive.swarm.authelia.url is null: every hive
+          authenticates to this collector as itself, and the token comes
+          from the swarm's identity provider.
+
+          Point authelia.url at the swarm's provider, or enable
+          services.hyperhive.swarm.authelia on the host that runs it.
+        '';
+      }
+      {
+        # A port collision between two listeners on one host is a runtime
+        # coin toss with nothing in any log — the failure this whole
+        # comment budget exists to prevent. Checked against every port
+        # reachable from here; a port some other module picks is not.
+        #
+        # ⚠️ `cfg.port` is deliberately absent from `others`: it is the
+        # FIRST element of the derived range, so listing it would make this
+        # assertion fire on every config.
+        assertion =
+          let
+            derived = lib.attrValues hivePorts;
+            others = [
+              cfg.telemetryPort
+              otelCfg.collector.port
+            ]
+            ++ lib.optional vmCfg.enable vmCfg.port;
+            all = derived ++ others;
+          in
+          lib.length (lib.unique all) == lib.length all;
+        message = ''
+          services.hyperhive.swarm.otel: the receiver range starting at
+          port (${toString cfg.port}, one port per hive in
+          services.hyperhive.swarm.hives) overlaps another port on this
+          host.
+
+          Every swarm container shares the host's network namespace, so
+          two listeners claiming one port is not a build failure — it is
+          whichever process started first, silently. Move
+          services.hyperhive.swarm.otel.port to a free range.
+        '';
+      }
     ];
 
     containers.${cfg.machine} = {
@@ -179,12 +317,16 @@ in
       # Read-only, and only when one is configured — binding a path that
       # does not exist makes nixos-container refuse to start the container,
       # which is a stall several layers from its cause.
-      bindMounts = lib.optionalAttrs (otelCfg.headersCredential != null) {
-        ${otelCfg.headersCredential} = {
-          hostPath = otelCfg.headersCredential;
-          isReadOnly = true;
-        };
-      };
+      bindMounts =
+        lib.optionalAttrs (otelCfg.headersCredential != null) {
+          ${otelCfg.headersCredential} = {
+            hostPath = otelCfg.headersCredential;
+            isReadOnly = true;
+          };
+        }
+        # The public hive CA, read-only — only when something in here
+        # actually verifies a swarm-service name.
+        // caTrust.bindMount;
 
       config =
         { ... }:
@@ -200,6 +342,18 @@ in
               inherit (config.services.hyperhive.network) bridgeIp;
               dnsConsumers = [ "opentelemetry-collector.service" ];
             })
+          ]
+          # `SSL_CERT_FILE` REPLACES the trust store rather than adding to
+          # it, so a failed assembly yields an empty pool and every TLS
+          # call fails while the unit looks healthy. That is why this is
+          # the shared helper — it carries the `Requires` and the
+          # non-empty check — and not a local `cat`.
+          ++ [
+            (caTrust.trustBundle {
+              inherit pkgs;
+              name = cfg.machine;
+              consumers = [ "opentelemetry-collector" ];
+            })
           ];
 
           system.stateVersion = config.system.stateVersion;
@@ -219,7 +373,24 @@ in
             # real sample through both tiers into the store.
             validateConfigFile = true;
             settings = {
-              receivers.otlp.protocols.http.endpoint = "127.0.0.1:${toString cfg.port}";
+              # One receiver per hive, and that multiplicity is forced
+              # rather than chosen. The `hive`
+              # label has to come from something the sender cannot write,
+              # and the only such thing here is WHICH RECEIVER accepted
+              # the sample: a processor cannot read the token's claims
+              # (`from_context` reads request metadata, and asking it for
+              # an auth claim yields nothing — silently, with a healthy
+              # startup), and one receiver holding many credentials never
+              # reveals which one matched.
+              receivers = lib.mapAttrs' (
+                h: p:
+                lib.nameValuePair "otlp/${h}" {
+                  protocols.http = {
+                    endpoint = "127.0.0.1:${toString p}";
+                    auth.authenticator = "oidc/${h}";
+                  };
+                }
+              ) hivePorts;
 
               exporters =
                 lib.optionalAttrs vmCfg.enable {
@@ -263,16 +434,64 @@ in
                 }
               ];
 
-              service.pipelines.metrics = {
-                receivers = [ "otlp" ];
-                # Fan-out, not a choice: with both configured the same
-                # samples go upstream AND into the swarm's store. The store
-                # is for looking at this swarm; the upstream is for whoever
-                # aggregates across swarms, and neither replaces the other.
-                exporters =
-                  lib.optional (otelCfg.endpoint != "") (if otelCfg.protocol == "grpc" then "otlp" else "otlphttp")
-                  ++ lib.optional vmCfg.enable "otlphttp/victoriametrics";
-              };
+              # ⚠️ An extension that is configured but not listed here is
+              # INERT — the collector starts clean and the receiver
+              # naming it authenticates nothing. Derived from the same
+              # attrset as the receivers so the two cannot disagree.
+              service.extensions = map (h: "oidc/${h}") (lib.attrNames hivePorts);
+
+              # Fan-out, not a choice: with both configured the same
+              # samples go upstream AND into the swarm's store. The store
+              # is for looking at this swarm; the upstream is for whoever
+              # aggregates across swarms, and neither replaces the other.
+              # `exporterNames` is shared by every pipeline — where a
+              # sample goes is a property of this tier, not of the hive
+              # that sent it.
+              service.pipelines = lib.mapAttrs' (
+                h: _:
+                lib.nameValuePair "metrics/${h}" {
+                  receivers = [ "otlp/${h}" ];
+                  processors = [ "resource/${h}" ];
+                  exporters = exporterNames;
+                }
+              ) hivePorts;
+            }
+            // {
+              extensions = lib.mapAttrs' (
+                h: _:
+                lib.nameValuePair "oidc/${h}" {
+                  issuer_url = autheliaCfg.url;
+                  # The audience this hive's client is registered to
+                  # request, and the reason one hive's token is refused by
+                  # another hive's receiver. Same expression authelia
+                  # registers it under — a second spelling here would deny
+                  # every hive, as a 401 that blames the token.
+                  audience = "${autheliaCfg.hiveClientPrefix}${h}";
+                  # ⚠️ `issuer_ca_path`. `issuer_ca_file`, `ca_file` and
+                  # `tls.ca_file` are all INVALID KEYS for this extension
+                  # — measured, and the failure is a startup error naming
+                  # the key rather than anything about certificates.
+                  issuer_ca_path = caBundle;
+                }
+              ) hivePorts;
+
+              # `upsert`, not `insert`: a sender that stamps its own
+              # `hive` must be OVERWRITTEN, not deferred to. This
+              # processor is the whole attribution boundary — the value
+              # is a constant per receiver, so it says which hive
+              # authenticated, not which hive claimed to be sending.
+              processors = lib.mapAttrs' (
+                h: _:
+                lib.nameValuePair "resource/${h}" {
+                  attributes = [
+                    {
+                      key = "hive";
+                      value = h;
+                      action = "upsert";
+                    }
+                  ];
+                }
+              ) hivePorts;
             };
           };