diff --git a/docs/agent-lifecycle/persistence.md b/docs/agent-lifecycle/persistence.md
index 5ad13f56..c5808cb1 100644
--- a/docs/agent-lifecycle/persistence.md
+++ b/docs/agent-lifecycle/persistence.md
@@ -278,7 +278,8 @@ Under `/var/lib/hyperhive/agents/<name>/`:
   logs an error naming both paths: claude loads only `CLAUDE.md` while
   one exists in its cwd or above. The harness also publishes the file
   to the swarm, which reads that copy, and applies the git diffs the
-  swarm sends to edit it. This file stays the only copy that counts:
+  swarm sends to edit it. A new agent's first start writes the text given at
+  create, only when no file exists. This file stays the only copy that counts:
   [`docs/swarm/README.md`](../swarm/README.md#an-agents-agentsmd).
 - `harness/` — harness-internal ephemeral state; not intended for
   agent consumption. Bind-mounted to `/agents/<name>/harness`
diff --git a/docs/swarm/README.md b/docs/swarm/README.md
index 9e0e4f2f..6c756914 100644
--- a/docs/swarm/README.md
+++ b/docs/swarm/README.md
@@ -328,6 +328,19 @@ publishes `""`. `GET /api/agents/<name>/agents-md` answers `{content, revision}`
 from that copy, so it works while the agent isn't running. A 404 means the agent
 hasn't published one: its harness hasn't run since it began to.
 
+**Initial text.** `POST /api/agents` and `swarmctl agent create --agents-md <file>`
+take an optional `agents_md`, the text the file starts with, up to 64 KiB; a
+longer text is a 400. The controller stores it under the key `<agent>` of the
+`agents-md-initial` bucket, which only it writes, before it queues the creation.
+At start the harness reads its own key, with one direct get on
+`$JS.API.DIRECT.GET.KV_agents-md-initial.$KV.agents-md-initial.<agent>`, and
+writes the text to `AGENTS.md` only when no file exists there. It does this
+before the first mirror publish and the first turn. An existing file is never
+replaced, so a restart or a re-create keeps the agent's edits; a later change
+to the file never reaches the key. Destroying the agent deletes the key. When
+the harness can't read the key it starts without the text and logs a warning.
+The text holds no secret, so nothing goes through the secret store.
+
 **Editing.** `PUT /api/agents/<name>/agents-md` takes `{base_revision, diff}`.
 The diff is a unified diff that names `a/AGENTS.md` and `b/AGENTS.md`, made
 against the text at `base_revision`. swarm-controller sends it as a request on
diff --git a/docs/tools/swarmctl-cli.md b/docs/tools/swarmctl-cli.md
index 6ec9956c..e032ad98 100644
--- a/docs/tools/swarmctl-cli.md
+++ b/docs/tools/swarmctl-cli.md
@@ -101,6 +101,9 @@ No approval gate guards this: the caller is root on the controller's host, or lo
 * `--hive <HIVE>` — Hive in this swarm to deploy the agent to.
 
    Required, and deliberately not defaulted: it's an *address* — the hive that gets the deploy message — and only the operator knows which one they mean. The controller checks it against the swarm's hive roster and names the known hives if it misses.
+* `--agents-md <FILE>` — A text file the agent's `AGENTS.md` starts with.
+
+   The agent writes it on its first start, and only when it has no `AGENTS.md` yet: re-creating an agent never replaces an existing file. The controller refuses a file over 64 KiB.
 * `--controller-socket <PATH>` — swarm-controller's unix socket.
 
    Supplied by the nix module that installs this binary, from the same `socketPath` option the daemon binds; falls back to `SWARM_CONTROLLER_SOCKET`.
diff --git a/hive-agent/Cargo.toml b/hive-agent/Cargo.toml
index 11e68f9c..37133008 100644
--- a/hive-agent/Cargo.toml
+++ b/hive-agent/Cargo.toml
@@ -49,6 +49,7 @@ swarm-queue-client = { workspace = true, features = [
   "agent-schedules",
   "agent-inference",
   "agent-permissions",
+  "agents-md-initial",
   "operator-profiles",
 ] }
 # This agent's own queue secret, read from the store under its own certificate.
diff --git a/hive-agent/src/main.rs b/hive-agent/src/main.rs
index 6d210163..c0a7dfb2 100644
--- a/hive-agent/src/main.rs
+++ b/hive-agent/src/main.rs
@@ -505,6 +505,8 @@ async fn serve_main<S: Surface>(socket: &Path, poll_ms: u64) -> Result<()> {
     swarm_agent_state::spawn(&bus, login_state.clone());
     // Once per start: a new icon only arrives with a new harness process.
     swarm_agent_icon::spawn();
+    // Before the mirror and before any turn reads the file.
+    swarm_agents_md::seed_initial().await;
     // At start and on every change, so the swarm can read it while the
     // agent is stopped.
     swarm_agents_md::spawn();
diff --git a/hive-agent/src/swarm_agents_md.rs b/hive-agent/src/swarm_agents_md.rs
index a968afe4..292358e8 100644
--- a/hive-agent/src/swarm_agents_md.rs
+++ b/hive-agent/src/swarm_agents_md.rs
@@ -29,6 +29,7 @@ use std::time::Duration;
 use async_nats::jetstream::context::PublishErrorKind;
 use sha1::{Digest as _, Sha1};
 use swarm_queue_client::agents_md::{Apply, ApplyReply, Mirror};
+use swarm_queue_client::agents_md_initial::Initial;
 use tokio::sync::Notify;
 
 use crate::claude_md_watch::agents_md_path;
@@ -94,6 +95,103 @@ pub fn spawn() {
     });
 }
 
+/// How many times, and for how long each, the key is read at start before the
+/// agent starts without the text.
+const SEED_ATTEMPTS: u32 = 3;
+const SEED_READ_TIMEOUT: Duration = Duration::from_secs(5);
+const SEED_RETRY_WAIT: Duration = Duration::from_secs(1);
+
+/// Write the text the swarm stored for this agent at create to `AGENTS.md`,
+/// when the file does not exist. Done before anything reads the file, so the
+/// agent's first turn already has it, and before the mirror, so the swarm
+/// sees it from the first publish.
+///
+/// An existing file is never touched, so a restart or a re-created agent
+/// keeps its edits. The read of the key is bounded to about
+/// [`SEED_ATTEMPTS`] × [`SEED_READ_TIMEOUT`], so a queue that refuses it delays
+/// boot by seconds; the agent then starts without the text and a later start
+/// tries again.
+pub async fn seed_initial() {
+    let agent = crate::identity::label();
+    let dir = crate::paths::state_dir();
+    if agent.is_empty() || exists(&agents_md_path(&dir)) {
+        return;
+    }
+    let client = crate::swarm_queue::client().await;
+    let read = read_bounded(SEED_ATTEMPTS, SEED_READ_TIMEOUT, SEED_RETRY_WAIT, || {
+        swarm_queue_client::agents_md_initial::read_own(&client, &agent)
+    })
+    .await;
+    match read {
+        Ok(initial) => {
+            if let Err(e) = seed(&dir, initial.as_ref()) {
+                tracing::warn!(error = %e, "writing the initial AGENTS.md failed");
+            }
+        }
+        Err(e) => {
+            tracing::warn!(error = %e, "reading the initial AGENTS.md failed; starting without it");
+        }
+    }
+}
+
+/// `read`, tried up to `attempts` times with `wait` between, each cut off
+/// after `timeout`. The first answer wins; the last failure is the error.
+async fn read_bounded<T, E, F, Fut>(
+    attempts: u32,
+    timeout: Duration,
+    wait: Duration,
+    mut read: F,
+) -> Result<T, String>
+where
+    F: FnMut() -> Fut,
+    Fut: Future<Output = Result<T, E>>,
+    E: std::fmt::Display,
+{
+    let mut last = String::new();
+    for attempt in 0..attempts {
+        if attempt > 0 {
+            tokio::time::sleep(wait).await;
+        }
+        match tokio::time::timeout(timeout, read()).await {
+            Ok(Ok(value)) => return Ok(value),
+            Ok(Err(e)) => last = e.to_string(),
+            Err(_) => last = format!("no answer within {timeout:?}"),
+        }
+    }
+    Err(last)
+}
+
+/// Whether anything, a dangling link included, is at `path`.
+fn exists(path: &Path) -> bool {
+    std::fs::symlink_metadata(path).is_ok()
+}
+
+/// Create `AGENTS.md` in `state_dir` with `initial`'s text, unless a file is
+/// already there. The text goes to a temporary file in the same directory
+/// first and is linked into place without replacing anything
+/// (`persist_noclobber`), so a failed write leaves no file and a file written
+/// meanwhile is kept.
+fn seed(state_dir: &Path, initial: Option<&Initial>) -> std::io::Result<()> {
+    use std::os::unix::fs::PermissionsExt as _;
+
+    let Some(initial) = initial else {
+        return Ok(());
+    };
+    std::fs::create_dir_all(state_dir)?;
+    let mut temp = tempfile::NamedTempFile::new_in(state_dir)?;
+    temp.write_all(initial.content.as_bytes())?;
+    temp.as_file()
+        .set_permissions(std::fs::Permissions::from_mode(0o644))?;
+    match temp.persist_noclobber(agents_md_path(state_dir)) {
+        Ok(_) => {
+            tracing::info!(bytes = initial.content.len(), "wrote the initial AGENTS.md");
+            Ok(())
+        }
+        Err(e) if e.error.kind() == std::io::ErrorKind::AlreadyExists => Ok(()),
+        Err(e) => Err(e.error),
+    }
+}
+
 /// What became of one mirror write.
 #[derive(Debug)]
 enum Published {
@@ -503,4 +601,95 @@ mod tests {
         assert_eq!(second.revision, revision(AFTER.as_bytes()));
         task.abort();
     }
+
+    fn initial(text: &str) -> swarm_queue_client::agents_md_initial::Initial {
+        swarm_queue_client::agents_md_initial::Initial {
+            content: text.to_owned(),
+        }
+    }
+
+    /// The stored text becomes the file when there is none, and the mirror's
+    /// revision then covers it.
+    #[test]
+    fn the_initial_text_is_written_when_there_is_no_file() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        super::seed(dir.path(), Some(&initial(BEFORE))).expect("seed");
+        assert_eq!(file(&dir), BEFORE);
+        // Presence control for the next two: nothing stored writes nothing.
+        let empty = tempfile::tempdir().expect("tempdir");
+        super::seed(empty.path(), None).expect("seed");
+        assert!(!empty.path().join("AGENTS.md").exists());
+    }
+
+    /// A file the agent already has, edited or not, is never replaced.
+    #[test]
+    fn an_existing_file_is_not_overwritten_by_the_initial_text() {
+        let dir = state(AFTER);
+        super::seed(dir.path(), Some(&initial(BEFORE))).expect("seed");
+        assert_eq!(file(&dir), AFTER);
+        let empty = state("");
+        super::seed(empty.path(), Some(&initial(BEFORE))).expect("seed");
+        assert_eq!(file(&empty), "", "an emptied file is still the agent's");
+    }
+
+    /// A second start, with the key still stored, keeps the agent's edits.
+    #[test]
+    fn a_second_seed_keeps_what_the_agent_did_with_the_file() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        super::seed(dir.path(), Some(&initial(BEFORE))).expect("seed");
+        std::fs::write(dir.path().join("AGENTS.md"), AFTER).expect("edit");
+        super::seed(dir.path(), Some(&initial(BEFORE))).expect("seed again");
+        assert_eq!(file(&dir), AFTER);
+    }
+
+    /// A seed that cannot finish leaves no `AGENTS.md`, so the next start
+    /// tries again. The state dir's parent is a file, so no temp file can be
+    /// made; the leftover directory listing is empty either way.
+    #[test]
+    fn a_seed_that_fails_leaves_no_file_and_no_temp_file() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        let blocker = dir.path().join("blocker");
+        std::fs::write(&blocker, "x").expect("write");
+        super::seed(&blocker.join("state"), Some(&initial(BEFORE))).expect_err("no dir");
+        assert!(!blocker.join("state").exists());
+        // Control: a good dir leaves exactly AGENTS.md, no temp file.
+        let ok = tempfile::tempdir().expect("tempdir");
+        super::seed(ok.path(), Some(&initial(BEFORE))).expect("seed");
+        let names: Vec<_> = std::fs::read_dir(ok.path())
+            .expect("ls")
+            .map(|e| e.expect("entry").file_name())
+            .collect();
+        assert_eq!(names, ["AGENTS.md"]);
+    }
+
+    /// A read that never answers costs `attempts` × `timeout` plus the waits,
+    /// not a startup retry schedule, and the last failure is reported.
+    #[tokio::test(start_paused = true)]
+    async fn a_read_that_never_answers_is_given_up_after_the_bound() {
+        let started = tokio::time::Instant::now();
+        let out = super::read_bounded(3, Duration::from_secs(5), Duration::from_secs(1), || {
+            std::future::pending::<Result<(), String>>()
+        })
+        .await;
+        assert!(out.unwrap_err().contains("no answer within"));
+        assert_eq!(started.elapsed(), Duration::from_secs(17));
+    }
+
+    /// A later attempt that answers wins over an earlier failure.
+    #[tokio::test(start_paused = true)]
+    async fn a_read_that_fails_once_and_then_answers_returns_the_answer() {
+        let calls = std::sync::atomic::AtomicU32::new(0);
+        let out = super::read_bounded(3, Duration::from_secs(5), Duration::from_secs(1), || {
+            let n = calls.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
+            async move {
+                if n == 0 {
+                    Err("down".to_owned())
+                } else {
+                    Ok(7)
+                }
+            }
+        })
+        .await;
+        assert_eq!(out, Ok(7));
+    }
 }
diff --git a/nix/host-modules/swarm-nats.nix b/nix/host-modules/swarm-nats.nix
index 14ed391e..69fab3de 100644
--- a/nix/host-modules/swarm-nats.nix
+++ b/nix/host-modules/swarm-nats.nix
@@ -909,6 +909,10 @@ in
                 # the harness and the subagent daemon read the tool permissions
                 # it holds.
                 "--agent-token-publish-subject ${lib.escapeShellArg "\$\$JS.API.DIRECT.GET.KV_agent-permissions.\$\$KV.agent-permissions.{agent}"}"
+                # Its own key of the `agents-md-initial` KV bucket
+                # (`swarm_queue_client::agents_md_initial`), on the same terms: the
+                # harness reads the text its `AGENTS.md` starts with.
+                "--agent-token-publish-subject ${lib.escapeShellArg "\$\$JS.API.DIRECT.GET.KV_agents-md-initial.\$\$KV.agents-md-initial.{agent}"}"
                 # Every agent also reads the operator list, the one key of the
                 # `operator-profiles` bucket, with one direct get. That grant
                 # names no agent, so the responder adds it itself
diff --git a/nix/module-eval/nats-authelia.nix b/nix/module-eval/nats-authelia.nix
index d725cecb..026765d2 100644
--- a/nix/module-eval/nats-authelia.nix
+++ b/nix/module-eval/nats-authelia.nix
@@ -505,6 +505,7 @@ let
           "'$$JS.API.DIRECT.GET.KV_agent-schedules.$$KV.agent-schedules.{agent}'"
           "'$$JS.API.DIRECT.GET.KV_agent-inference.$$KV.agent-inference.{agent}'"
           "'$$JS.API.DIRECT.GET.KV_agent-permissions.$$KV.agent-permissions.{agent}'"
+          "'$$JS.API.DIRECT.GET.KV_agents-md-initial.$$KV.agents-md-initial.{agent}'"
         ];
     }
     {
diff --git a/swarm-controller/README.md b/swarm-controller/README.md
index 346b0071..0176caf7 100644
--- a/swarm-controller/README.md
+++ b/swarm-controller/README.md
@@ -62,7 +62,9 @@ The swarm's control plane. The swarm UI and `swarmctl` are its clients.
   published it into the `agents-md` KV bucket
   (`GET /api/agents/{name}/agents-md`), and edits to it as git diffs, which
   this daemon hands to the agent's harness to apply
-  (`PUT /api/agents/{name}/agents-md`) →
+  (`PUT /api/agents/{name}/agents-md`). `POST /api/agents` can set the text the
+  file starts with (`agents_md`), stored in the `agents-md-initial` bucket for
+  the harness to write when no file exists →
   [`docs/swarm/README.md`](../docs/swarm/README.md#an-agents-agentsmd).
 - **Review classifier** — try-outs from the swarm UI and reviews on review
   requests, and the newest 100 finished runs, one document in the
diff --git a/swarm-controller/src/agent_permissions.rs b/swarm-controller/src/agent_permissions.rs
index 251f457e..8bb65c28 100644
--- a/swarm-controller/src/agent_permissions.rs
+++ b/swarm-controller/src/agent_permissions.rs
@@ -812,6 +812,7 @@ mod tests {
                     inference: None,
                     permissions,
                     archetype: None,
+                    agents_md: None,
                 }),
             )
         };
@@ -873,6 +874,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
diff --git a/swarm-controller/src/agents_md_initial.rs b/swarm-controller/src/agents_md_initial.rs
new file mode 100644
index 00000000..235ddc2c
--- /dev/null
+++ b/swarm-controller/src/agents_md_initial.rs
@@ -0,0 +1,252 @@
+//! The text an agent's `AGENTS.md` starts with: one key per agent in
+//! `agents-md-initial` (`swarm_queue_client::agents_md_initial`), which this
+//! daemon alone writes. `POST /api/agents` stores it before it queues the
+//! creation; a destroy deletes it. The agent's harness reads its own key at
+//! start and writes the file only when none exists.
+
+use problem_details::ProblemDetails;
+use swarm_queue_client::agents_md_initial::{self, Initial, MAX_BYTES};
+
+use crate::routes::{AppState, error_problem};
+use crate::schedules::{queue, read_or_default, write_revision};
+
+/// How many times a losing writer re-reads and re-applies, as in
+/// `wanted::MAX_ATTEMPTS`.
+const MAX_ATTEMPTS: usize = 5;
+
+fn queue_problem(e: &anyhow::Error) -> ProblemDetails {
+    tracing::warn!(error = %format!("{e:#}"), "agents-md initial text: queue operation failed");
+    error_problem(
+        axum::http::StatusCode::INTERNAL_SERVER_ERROR,
+        &format!("{e:#}"),
+    )
+}
+
+/// Refuse a text longer than [`MAX_BYTES`].
+pub(crate) fn check(content: &str) -> Result<(), String> {
+    if content.len() > MAX_BYTES {
+        return Err(format!(
+            "agents_md is {} bytes; the limit is {MAX_BYTES}",
+            content.len()
+        ));
+    }
+    Ok(())
+}
+
+/// What [`store`] replaced, for [`restore`]; `None` when it wrote nothing.
+pub(crate) type Replaced = Option<crate::schedules::Replaced<Initial>>;
+
+/// Record that `agent`'s `AGENTS.md` starts with `content`.
+pub(crate) async fn store(
+    client: &async_nats::Client,
+    agent: &str,
+    content: &str,
+) -> Result<Replaced, ProblemDetails> {
+    let store = agents_md_initial::open_or_create(client)
+        .await
+        .map_err(|e| queue_problem(&e.into()))?;
+    let value = Initial {
+        content: content.to_owned(),
+    };
+    for _ in 0..MAX_ATTEMPTS {
+        let (current, revision, undecodable) = read_or_default::<Initial>(&store, agent)
+            .await
+            .map_err(|e| queue_problem(&e))?;
+        // An absent key reads as the default, which is not "stored": a first
+        // write of an empty text still has to land.
+        if current == value && !undecodable && revision.is_some() {
+            return Ok(None);
+        }
+        if let Some(written) = write_revision(&store, agent, &value, revision)
+            .await
+            .map_err(|e| queue_problem(&e))?
+        {
+            tracing::info!(%agent, bytes = content.len(), "set agent's initial AGENTS.md at create");
+            return Ok(Some(crate::schedules::Replaced::new(
+                revision.map(|_| current),
+                written,
+            )));
+        }
+    }
+    Err(queue_problem(&anyhow::anyhow!(
+        "gave up writing the initial AGENTS.md of {agent} after {MAX_ATTEMPTS} conflicting writes"
+    )))
+}
+
+/// Undo what [`store`] did, unless another write has landed since. Best
+/// effort: a failure is logged, since the caller is already on its way to an
+/// error of its own.
+pub(crate) async fn restore(client: &async_nats::Client, agent: &str, replaced: Replaced) {
+    let Some(replaced) = replaced else { return };
+    let undone = match agents_md_initial::open_or_create(client).await {
+        Ok(store) => replaced.undo(&store, agent).await,
+        Err(e) => Err(anyhow::anyhow!("{e:?}")),
+    };
+    match undone {
+        Ok(true) => {}
+        Ok(false) => {
+            tracing::info!(%agent, "left the agent's initial AGENTS.md: another write landed since");
+        }
+        Err(e) => {
+            tracing::warn!(%agent, error = %format!("{e:#}"), "could not put back the agent's initial AGENTS.md");
+        }
+    }
+}
+
+/// Delete a destroyed agent's key, so the next agent of that name does not
+/// start from this one's text. A failure is logged and does not stop the
+/// destroy, as in `agent_archetype::clear_on_destroy`.
+pub(crate) async fn clear_on_destroy(state: &AppState, hive: &str, agent: &str) {
+    let cleared = async {
+        let client = queue(state).map_err(|(_, why)| anyhow::anyhow!(why))?;
+        agents_md_initial::open_or_create(&client)
+            .await?
+            .delete(agent)
+            .await?;
+        anyhow::Ok(())
+    }
+    .await;
+    match cleared {
+        Ok(()) => tracing::info!(hive, agent, "destroyed agent's initial AGENTS.md cleared"),
+        Err(e) => tracing::error!(
+            hive,
+            agent,
+            error = %format!("{e:#}"),
+            "clearing this agent's initial AGENTS.md FAILED; it was destroyed anyway, so a new \
+             agent of the same name starts from this text. Declaring the agent destroyed again \
+             re-runs this."
+        ),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use axum::extract::{Path, State};
+    use axum::http::StatusCode;
+
+    use super::*;
+    use crate::test_nats::TestNats;
+
+    async fn published(client: &async_nats::Client, agent: &str) -> Option<String> {
+        let store = agents_md_initial::open_or_create(client)
+            .await
+            .expect("bucket");
+        store
+            .get(agent)
+            .await
+            .expect("read")
+            .map(|v| String::from_utf8(v.to_vec()).expect("utf-8"))
+    }
+
+    fn request(name: &str, agents_md: Option<String>) -> crate::routes::agents::CreateAgentRequest {
+        crate::routes::agents::CreateAgentRequest {
+            name: name.to_owned(),
+            hive: "pr1ma".to_owned(),
+            limits: None,
+            inference: None,
+            permissions: None,
+            archetype: None,
+            agents_md,
+        }
+    }
+
+    #[test]
+    fn a_text_over_the_limit_is_refused_and_one_at_it_passes() {
+        assert_eq!(check(&"a".repeat(MAX_BYTES)), Ok(()));
+        let why = check(&"a".repeat(MAX_BYTES + 1)).unwrap_err();
+        assert!(why.contains("the limit is"), "{why}");
+    }
+
+    /// `POST /api/agents` with `agents_md` stores it under the new agent's
+    /// key; a text over the limit is refused before anything is stored or
+    /// queued.
+    #[tokio::test]
+    async fn create_stores_the_text_it_is_given_and_refuses_one_too_big() {
+        let nats = TestNats::start();
+        let client = nats.client().await;
+        let state = crate::agent_limits::tests::declared(&client).await;
+
+        let problem = crate::routes::agents::create_agent(
+            State(state.clone()),
+            axum::Json(request("iris", Some("a".repeat(MAX_BYTES + 1)))),
+        )
+        .await
+        .expect_err("too big");
+        assert_eq!(problem.status, Some(StatusCode::BAD_REQUEST), "{problem:?}");
+        assert_eq!(published(&client, "iris").await, None);
+        let queued = state
+            .jobq
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .graph()
+            .nodes()
+            .count();
+        assert_eq!(queued, 0, "nothing is queued for a refused create");
+
+        let _ = crate::routes::agents::create_agent(
+            State(state.clone()),
+            axum::Json(request("iris", Some("# iris\n".to_owned()))),
+        )
+        .await
+        .expect("created");
+        assert_eq!(
+            published(&client, "iris").await.as_deref(),
+            Some(r##"{"content":"# iris\n"}"##)
+        );
+
+        // Control: no `agents_md` writes no key.
+        let _ = crate::routes::agents::create_agent(
+            State(state.clone()),
+            axum::Json(request("damocles", None)),
+        )
+        .await
+        .expect("created");
+        assert_eq!(published(&client, "damocles").await, None);
+    }
+
+    /// An empty text is a text: the key is written, so the agent gets an
+    /// empty file rather than none.
+    #[tokio::test]
+    async fn an_empty_text_is_stored() {
+        let nats = TestNats::start();
+        let client = nats.client().await;
+        let state = crate::agent_limits::tests::declared(&client).await;
+        let _ = crate::routes::agents::create_agent(
+            State(state.clone()),
+            axum::Json(request("iris", Some(String::new()))),
+        )
+        .await
+        .expect("created");
+        assert_eq!(
+            published(&client, "iris").await.as_deref(),
+            Some(r#"{"content":""}"#)
+        );
+    }
+
+    /// Destroying an agent deletes its key, so a new agent of that name does
+    /// not start from the old text.
+    #[tokio::test]
+    async fn a_recreated_agent_does_not_start_from_the_destroyed_ones_text() {
+        let nats = TestNats::start();
+        let client = nats.client().await;
+        let state = crate::agent_limits::tests::declared(&client).await;
+        let _ = crate::routes::agents::create_agent(
+            State(state.clone()),
+            axum::Json(request("atlas", Some("old".to_owned()))),
+        )
+        .await
+        .expect("created");
+        assert!(published(&client, "atlas").await.is_some());
+
+        let _ = crate::routes::agents::set_agent_state(
+            State(state.clone()),
+            Path(("pr1ma".to_owned(), "atlas".to_owned())),
+            axum::Json(crate::routes::agents::SetAgentStateRequest {
+                state: swarm_queue_client::wanted::AgentState::Destroyed,
+            }),
+        )
+        .await
+        .expect("destroyed");
+        assert_eq!(published(&client, "atlas").await, None);
+    }
+}
diff --git a/swarm-controller/src/jobq.rs b/swarm-controller/src/jobq.rs
index 908da079..54cb4ee6 100644
--- a/swarm-controller/src/jobq.rs
+++ b/swarm-controller/src/jobq.rs
@@ -1688,6 +1688,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
@@ -1810,6 +1811,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
@@ -1861,6 +1863,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
@@ -1920,6 +1923,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
@@ -2126,6 +2130,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
diff --git a/swarm-controller/src/main.rs b/swarm-controller/src/main.rs
index 59b114b2..1e927f79 100644
--- a/swarm-controller/src/main.rs
+++ b/swarm-controller/src/main.rs
@@ -33,6 +33,7 @@ mod agent_renewal;
 mod agent_state_stream;
 mod agent_status;
 mod agents_md;
+mod agents_md_initial;
 mod alerts;
 mod archetypes;
 mod auth;
diff --git a/swarm-controller/src/routes/agents.rs b/swarm-controller/src/routes/agents.rs
index 49cff3aa..c8fd7218 100644
--- a/swarm-controller/src/routes/agents.rs
+++ b/swarm-controller/src/routes/agents.rs
@@ -16,8 +16,8 @@ use crate::jobq::{SwarmNodeKind, SwarmResourceKind, declare_agent_job};
 use crate::routes::hives::HiveEntry;
 use crate::routes::{AppState, StatusUnavailable, error_problem, wanted_error_status};
 use crate::{
-    agent_archetype, agent_identity, agent_limits, agent_permissions, agent_status, auth,
-    inference, schedules, wanted,
+    agent_archetype, agent_identity, agent_limits, agent_permissions, agent_status,
+    agents_md_initial, auth, inference, schedules, wanted,
 };
 
 /// The swarm's agent roster — every agent the swarm holds an identity for.
@@ -214,6 +214,7 @@ pub(crate) async fn set_agent_state(
         revoke_or_complain(&hive, &agent).await;
         agent_permissions::clear_on_destroy(&state, &hive, &agent).await;
         agent_archetype::clear_on_destroy(&state, &hive, &agent).await;
+        agents_md_initial::clear_on_destroy(&state, &hive, &agent).await;
     }
     Ok(Json(render(&declaration)))
 }
@@ -516,6 +517,13 @@ pub(crate) struct CreateAgentRequest {
     #[serde(default)]
     #[schema(value_type = Option<Object>, example = json!({"source": "hyperhive", "name": "reviewer"}))]
     pub(crate) archetype: Option<swarm_queue_client::agent_archetype::ArchetypeRef>,
+    /// The text the agent's `AGENTS.md` starts with, at most
+    /// `swarm_queue_client::agents_md_initial::MAX_BYTES` bytes. The agent's
+    /// harness writes it on its first start, and only when the agent has no
+    /// `AGENTS.md` yet: an existing file is never replaced. Absent leaves the
+    /// file to the harness.
+    #[serde(default)]
+    pub(crate) agents_md: Option<String>,
 }
 
 /// Queue the whole agent-creation job graph for `name` — two independent
@@ -549,10 +557,10 @@ pub(crate) struct CreateAgentRequest {
     request_body = CreateAgentRequest,
     responses(
         (status = 200, description = "job chain queued", body = CreateAgentResponse),
-        (status = 400, description = "`name` or `hive` is not a valid identifier, `name` is new and reserved or refused by the forge, `hive` is not in this swarm, `limits` or `inference` holds a value the matching `PUT` refuses, a permission is listed twice, or `archetype` is not one the stored archetype list holds (problem+json)", body = String),
+        (status = 400, description = "`name` or `hive` is not a valid identifier, `name` is new and reserved or refused by the forge, `hive` is not in this swarm, `limits` or `inference` holds a value the matching `PUT` refuses, a permission is listed twice, `archetype` is not one the stored archetype list holds, or `agents_md` is over the size limit (problem+json)", body = String),
         (status = 409, description = "the swarm has already placed `name` on a different hive (problem+json)", body = String),
         (status = 422, description = "an unknown field in the body, in `limits`, or in `inference`, an `effort` that is not one of the five levels, or a `permissions` entry that is not a permission name"),
-        (status = 503, description = "the swarm queue is not connected, so whether `name` is placed on another hive is unknown, or `limits`, `inference`, `permissions` or `archetype` is set and cannot be stored (problem+json)", body = String),
+        (status = 503, description = "the swarm queue is not connected, so whether `name` is placed on another hive is unknown, or `limits`, `inference`, `permissions`, `archetype` or `agents_md` is set and cannot be stored (problem+json)", body = String),
         (status = 500, description = "the job chain could not be queued, or another hive's wanted state could not be read (problem+json)", body = String),
     ),
     tag = "agents"
@@ -567,7 +575,7 @@ pub(crate) async fn create_agent(
 
     // Settings are checked before anything is created, so a bad value stops
     // the request rather than leaving an agent without them.
-    let settings = CreateSettings::parse(req.limits, req.inference, req.permissions, req.archetype)
+    let settings = CreateSettings::parse(&req)
         .map_err(|why| error_problem(axum::http::StatusCode::BAD_REQUEST, &why))?;
 
     // Two checks, and the second is the one that makes the field worth
@@ -665,6 +673,7 @@ pub(crate) async fn create_agent(
                 settings.inference.as_ref(),
                 settings.permissions.as_ref(),
                 settings.archetype.as_ref(),
+                settings.agents_md.as_deref(),
             )
             .await?
         }
@@ -706,18 +715,25 @@ struct CreateSettings {
     inference: Option<swarm_queue_client::agent_inference::AgentInference>,
     permissions: Option<swarm_queue_client::agent_permissions::AgentPermissions>,
     archetype: Option<swarm_queue_client::agent_archetype::ArchetypeRef>,
+    agents_md: Option<String>,
 }
 
 impl CreateSettings {
     /// Each setting given, or why its `PUT` would refuse the first bad one.
     /// An archetype is checked here for its shape only; whether the swarm
     /// lists it is [`agent_archetype::check`].
-    fn parse(
-        limits: Option<agent_limits::Caps>,
-        inference: Option<inference::InferenceSettings>,
-        permissions: Option<Vec<hive_sh4re::permissions::Permission>>,
-        archetype: Option<swarm_queue_client::agent_archetype::ArchetypeRef>,
-    ) -> Result<Self, String> {
+    fn parse(req: &CreateAgentRequest) -> Result<Self, String> {
+        let CreateAgentRequest {
+            limits,
+            inference,
+            permissions,
+            archetype,
+            agents_md,
+            ..
+        } = req.clone();
+        if let Some(text) = &agents_md {
+            agents_md_initial::check(text)?;
+        }
         if let Some(a) = &archetype {
             for part in [&a.source, &a.name] {
                 hive_types::Ident::parse(part)
@@ -731,6 +747,7 @@ impl CreateSettings {
                 .transpose()?,
             permissions: permissions.map(agent_permissions::at_create).transpose()?,
             archetype,
+            agents_md,
         })
     }
 
@@ -740,6 +757,7 @@ impl CreateSettings {
             || self.inference.is_some()
             || self.permissions.is_some()
             || self.archetype.is_some()
+            || self.agents_md.is_some()
     }
 
     /// The queue to store the settings through, `None` when none is given.
@@ -767,10 +785,11 @@ struct StoredSettings {
     inference: inference::Replaced,
     permissions: agent_permissions::Replaced,
     archetype: agent_archetype::Replaced,
+    agents_md: agents_md_initial::Replaced,
 }
 
 impl StoredSettings {
-    /// Store whichever of `limits`, `permissions`, `inference` and `archetype` are
+    /// Store whichever of `limits`, `permissions`, `inference`, `archetype` and `agents_md` are
     /// given, in that order. A failure on one puts back the ones stored before it.
     async fn store(
         client: &async_nats::Client,
@@ -779,6 +798,7 @@ impl StoredSettings {
         inference: Option<&swarm_queue_client::agent_inference::AgentInference>,
         permissions: Option<&swarm_queue_client::agent_permissions::AgentPermissions>,
         archetype: Option<&swarm_queue_client::agent_archetype::ArchetypeRef>,
+        agents_md: Option<&str>,
     ) -> Result<Self, problem_details::ProblemDetails> {
         let mut stored = Self::default();
         if let Some(limits) = limits {
@@ -811,6 +831,15 @@ impl StoredSettings {
                 }
             }
         }
+        if let Some(text) = agents_md {
+            match agents_md_initial::store(client, agent, text).await {
+                Ok(replaced) => stored.agents_md = replaced,
+                Err(e) => {
+                    stored.roll_back(client, agent).await;
+                    return Err(e);
+                }
+            }
+        }
         Ok(stored)
     }
 
@@ -819,6 +848,7 @@ impl StoredSettings {
         inference::restore(client, agent, self.inference).await;
         agent_permissions::restore(client, agent, self.permissions).await;
         agent_archetype::restore(client, agent, self.archetype).await;
+        agents_md_initial::restore(client, agent, self.agents_md).await;
     }
 }
 
@@ -1238,6 +1268,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
@@ -1280,6 +1311,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
@@ -1444,6 +1476,7 @@ mod tests {
                 Some(&inference),
                 None,
                 None,
+                None,
             )
             .await;
             assert!(stored.is_err(), "{agent}: the inference write must fail");
@@ -1583,6 +1616,7 @@ mod tests {
                 inference: None,
                 permissions: None,
                 archetype: None,
+                agents_md: None,
             }),
         )
         .await
diff --git a/swarm-queue-client/Cargo.toml b/swarm-queue-client/Cargo.toml
index b7a590c0..90d0987c 100644
--- a/swarm-queue-client/Cargo.toml
+++ b/swarm-queue-client/Cargo.toml
@@ -62,6 +62,10 @@ agent-permissions = ["dep:hive-sh4re", "async-nats/jetstream"]
 # `agent_archetype::read`, for hive-c0re, which reads the archetype of each
 # agent it provisions or rebuilds. Explicit for the same reason as `notices`.
 agent-archetype = ["async-nats/jetstream"]
+# `agents_md_initial::read_own`, for the agent harness, which reads its own
+# initial `AGENTS.md` text with one direct get. Explicit for the same reason as
+# `notices`.
+agents-md-initial = ["async-nats/jetstream"]
 
 [dependencies]
 # Bare (no `kv`/`jetstream`) unless a consumer opts into the `kv` feature
diff --git a/swarm-queue-client/src/agents_md_initial.rs b/swarm-queue-client/src/agents_md_initial.rs
new file mode 100644
index 00000000..1a47b6dc
--- /dev/null
+++ b/swarm-queue-client/src/agents_md_initial.rs
@@ -0,0 +1,140 @@
+//! The text an agent's `AGENTS.md` starts with: one key per agent in the
+//! `agents-md-initial` KV bucket, set when the agent is created.
+//!
+//! **swarm-controller is the only writer**: `POST /api/agents` stores the key
+//! before it queues the agent's creation, and a destroy deletes it.
+//!
+//! **The agent's harness reads its own key** when it starts, and writes the
+//! text to `AGENTS.md` only when the file does not exist. The file in the
+//! agent's state dir stays the truth ([`crate::agents_md`]); this key is not
+//! read again once the file exists, and later edits never reach it.
+//!
+//! Keyed by the agent alone, like [`crate::agent_archetype`]. The agent's
+//! credential is granted one direct get on its own key and nothing else of
+//! the bucket.
+
+/// The KV bucket the initial texts are stored in, keyed by agent name.
+pub const BUCKET: &str = "agents-md-initial";
+
+/// The stream backing [`BUCKET`]. `create_key_value` prefixes `KV_`.
+pub const STREAM: &str = "KV_agents-md-initial";
+
+/// The longest initial text, in bytes. The agent mirrors the file into
+/// [`crate::agents_md`] whole, so the limit keeps it well under the queue's
+/// payload limit.
+pub const MAX_BYTES: usize = 64 * 1024;
+
+/// The subject `agent`'s entry is stored under.
+#[must_use]
+pub fn key_subject(agent: &str) -> String {
+    format!("$KV.{BUCKET}.{agent}")
+}
+
+/// The request subject that reads `agent`'s current entry.
+#[must_use]
+pub fn direct_get_subject(agent: &str) -> String {
+    format!("$JS.API.DIRECT.GET.{STREAM}.{}", key_subject(agent))
+}
+
+/// The value under an agent's key.
+#[derive(Debug, Clone, Default, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+pub struct Initial {
+    /// The text `AGENTS.md` starts with.
+    pub content: String,
+}
+
+/// Open the bucket for writing, creating it if nothing has yet.
+///
+/// **Controller-side only.** `history: 1`: the agent wants the current value.
+#[cfg(feature = "kv")]
+pub async fn open_or_create(
+    client: &async_nats::Client,
+) -> Result<async_nats::jetstream::kv::Store, crate::Error> {
+    let js = async_nats::jetstream::new(client.clone());
+    crate::kv::open_or_create(
+        &js,
+        BUCKET,
+        "agents-md-initial",
+        "The text each agent's AGENTS.md starts with, set by the swarm controller".to_owned(),
+    )
+    .await
+}
+
+/// Read `agent`'s own entry with one direct get. `None` when the key is
+/// absent or deleted, or when no bucket exists yet.
+///
+/// # Errors
+///
+/// A failed request or an undecodable value. A request the queue refused for
+/// permissions reaches the client as a timeout, not as a refusal.
+#[cfg(feature = "agents-md-initial")]
+pub async fn read_own(
+    client: &async_nats::Client,
+    agent: &str,
+) -> Result<Option<Initial>, Box<dyn std::error::Error + Send + Sync>> {
+    use async_nats::jetstream::stream::DirectGetErrorKind;
+
+    let js = async_nats::jetstream::new(client.clone());
+    let stream = js.get_stream_no_info(STREAM).await?;
+    let message = match stream.direct_get_last_for_subject(key_subject(agent)).await {
+        Ok(message) => message,
+        Err(e) if matches!(e.kind(), DirectGetErrorKind::NotFound) => return Ok(None),
+        Err(e)
+            if matches!(
+                e.kind(),
+                DirectGetErrorKind::ErrorResponse(status, _)
+                    if status == async_nats::StatusCode::NO_RESPONDERS
+            ) =>
+        {
+            return Ok(None);
+        }
+        Err(e) => return Err(e.into()),
+    };
+    Ok(decode(
+        message
+            .headers
+            .get("KV-Operation")
+            .map(async_nats::HeaderValue::as_str),
+        &message.payload,
+    )?)
+}
+
+/// One stored message as a value: a KV delete or purge is stored as an empty
+/// marker carrying the `KV-Operation` header, and reads as no entry.
+#[cfg(feature = "agents-md-initial")]
+fn decode(operation: Option<&str>, payload: &[u8]) -> serde_json::Result<Option<Initial>> {
+    if matches!(operation, Some("DEL" | "PURGE")) {
+        return Ok(None);
+    }
+    serde_json::from_slice(payload).map(Some)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// The names the grant in `swarm-nats-auth` is built from.
+    #[test]
+    fn names_match_the_queue_grant() {
+        assert_eq!(STREAM, format!("KV_{BUCKET}"));
+        assert_eq!(key_subject("iris"), "$KV.agents-md-initial.iris");
+        assert_eq!(
+            direct_get_subject("iris"),
+            "$JS.API.DIRECT.GET.KV_agents-md-initial.$KV.agents-md-initial.iris"
+        );
+    }
+
+    /// A stored text reads back, a delete is no entry.
+    #[cfg(feature = "agents-md-initial")]
+    #[test]
+    fn decoding_reads_the_text_and_a_delete_as_none() {
+        assert_eq!(
+            decode(None, br##"{"content":"# hi\n","later":1}"##).unwrap(),
+            Some(Initial {
+                content: "# hi\n".to_owned()
+            })
+        );
+        assert_eq!(decode(Some("DEL"), b"").unwrap(), None);
+        assert_eq!(decode(Some("PURGE"), b"").unwrap(), None);
+    }
+}
diff --git a/swarm-queue-client/src/lib.rs b/swarm-queue-client/src/lib.rs
index 534e933e..cc74a575 100644
--- a/swarm-queue-client/src/lib.rs
+++ b/swarm-queue-client/src/lib.rs
@@ -214,6 +214,11 @@ pub mod agent_icon;
 /// `kv`.
 pub mod agents_md;
 
+/// The text each agent's `AGENTS.md` starts with, set at create. The names and
+/// types are unconditional; opening the bucket needs `kv`, reading it
+/// `agents-md-initial`.
+pub mod agents_md_initial;
+
 /// The bucket swarm-controller declares each agent's scheduled prompts in —
 /// one key per agent, read by that agent alone. The names are unconditional;
 /// writing needs `kv` and reading needs `agent-schedules`.
diff --git a/swarmctl/src/agent.rs b/swarmctl/src/agent.rs
index b71fa1a5..20827fc3 100644
--- a/swarmctl/src/agent.rs
+++ b/swarmctl/src/agent.rs
@@ -41,6 +41,9 @@ struct CreateAgentRequest<'a> {
     /// endpoint and not defaulted anywhere, because it is only knowable
     /// from the operator making the choice.
     hive: &'a str,
+    /// The text the agent's `AGENTS.md` starts with; left out when not given.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    agents_md: Option<&'a str>,
 }
 
 /// Run `swarmctl agent create`.
@@ -50,19 +53,30 @@ struct CreateAgentRequest<'a> {
 /// built here keeps that cost inside the one arm that incurs it, the same
 /// way `PathArgs::resolve` is called only in the arms that need the
 /// deployment's env vars.
-pub(crate) fn create(target: &Target, name: &str, hive: &str) -> Result<()> {
+pub(crate) fn create(
+    target: &Target,
+    name: &str,
+    hive: &str,
+    agents_md: Option<&Path>,
+) -> Result<()> {
     // Client-side before the round trip, so a typo is an immediate local
     // error rather than a 400 the operator has to wait for. The controller
     // validates both again — that is the gate that matters, this is the
     // one that is fast.
     let name = parse_ident(name, "agent name")?;
     let hive = parse_ident(hive, "hive")?;
+    let agents_md = agents_md
+        .map(|path| {
+            std::fs::read_to_string(path)
+                .with_context(|| format!("reading --agents-md {}", path.display()))
+        })
+        .transpose()?;
 
     let rt = tokio::runtime::Builder::new_current_thread()
         .enable_all()
         .build()
         .context("starting a tokio runtime for the controller request")?;
-    let resp = rt.block_on(post_create(target, &name, &hive))?;
+    let resp = rt.block_on(post_create(target, &name, &hive, agents_md.as_deref()))?;
 
     println!("queued: job node {}", resp.node_id);
     println!(
@@ -114,11 +128,20 @@ pub(crate) fn mint_forge_token(target: &Target, name: &str) -> Result<()> {
 }
 
 /// One `POST /api/agents` round trip at the controller.
-async fn post_create(target: &Target, name: &str, hive: &str) -> Result<CreateAgentResponse> {
+async fn post_create(
+    target: &Target,
+    name: &str,
+    hive: &str,
+    agents_md: Option<&str>,
+) -> Result<CreateAgentResponse> {
     post(
         target,
         "/api/agents",
-        &CreateAgentRequest { name, hive },
+        &CreateAgentRequest {
+            name,
+            hive,
+            agents_md,
+        },
         "create-agent",
     )
     .await
diff --git a/swarmctl/src/main.rs b/swarmctl/src/main.rs
index 35352ca2..e6ec9442 100644
--- a/swarmctl/src/main.rs
+++ b/swarmctl/src/main.rs
@@ -426,6 +426,13 @@ struct AgentCreateArgs {
     /// hive roster and names the known hives if it misses.
     #[arg(long, value_name = "HIVE")]
     hive: String,
+    /// A text file the agent's `AGENTS.md` starts with.
+    ///
+    /// The agent writes it on its first start, and only when it has no
+    /// `AGENTS.md` yet: re-creating an agent never replaces an existing file.
+    /// The controller refuses a file over 64 KiB.
+    #[arg(long, value_name = "FILE")]
+    agents_md: Option<PathBuf>,
     /// swarm-controller's unix socket.
     ///
     /// Supplied by the nix module that installs this binary, from the same
@@ -668,7 +675,7 @@ fn main() -> Result<()> {
             command: AgentVerb::Create(args),
         } => {
             let target = remote.target(args.controller_socket)?;
-            agent::create(&target, &args.name, &args.hive)
+            agent::create(&target, &args.name, &args.hive, args.agents_md.as_deref())
         }
         // Same socket-resolution reasoning as `Create` above.
         Verb::Agent {