sec(auth): a mission's door token is revoked when the mission ends

The skills-door token was minted with a 24 h TTL and nothing revoked it
sooner, so a mission that finished in twenty minutes left a live
credential in its container for the rest of the day. auth_sessions gains
mission_id (ON DELETE CASCADE, so a purge revokes too);
mint_scoped_for_mission records it; revoke_mission_sessions deletes it.
Revocation runs on both terminal paths — the runner's close (RETURNING
the closed ids) and the operator's stop — and says how many it cleared.

Granularity is the mission, not the phase: the container and its door
are installed once per mission and serve every phase. Lingering
Authority (arXiv 2606.22504) is the reference. Tests: a minted token
authenticates for its scope and not as a full session, is dead after
revoke, and another mission's token is untouched; the harness gatepolicy
scenario now runs on the index arm and asserts the server revoked ≥1,
no row carries the mission, and the door answers 401 to the token.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01WZb5A2kfVfjpdwSochkuHz

crates/cm-api/src/mission_orchestrator.rs

@@ -955,11 +955,19 @@ async fn install_skills_door(
         );
         return false;
     };
-    // Outlives the longest mission we have seen, and expires on its own so a
-    // leaked container does not leave a live credential behind indefinitely.
+    // Bound to the mission: revoked by `revoke_mission_credentials` the
+    // moment it reaches a terminal status. The 24 h TTL is the backstop for a
+    // mission nothing ever closes, not the credential's lifetime — until
+    // 2026-09-20 it was, and a twenty-minute mission left a live token in
+    // its container for the other twenty-three hours.
     let auth = cm_auth::AuthService::new(pool.clone());
     let token = match auth
-        .mint_scoped(user_id, cm_auth::SCOPE_SKILLS_READ, time::Duration::hours(24))
+        .mint_scoped_for_mission(
+            user_id,
+            cm_auth::SCOPE_SKILLS_READ,
+            time::Duration::hours(24),
+            mission_id,
+        )
         .await
     {
         Ok(t) => t,
@@ -1093,3 +1101,24 @@ async fn record_skill_delivery(pool: &PgPool, mission_id: Uuid, mode: crate::ski
         );
     }
 }
+
+/// Revoke every credential minted for a mission. Called on every path that
+/// takes a mission to a terminal status — the runner's close and the
+/// operator's stop — so the authority a mission was given ends with it.
+/// Best-effort and loud: a revocation that failed is logged with the count
+/// it could not clear, which is the number an operator needs.
+pub async fn revoke_mission_credentials(pool: &PgPool, mission_id: Uuid) {
+    match cm_auth::AuthService::new(pool.clone())
+        .revoke_mission_sessions(mission_id)
+        .await
+    {
+        Ok(0) => {}
+        Ok(n) => eprintln!(
+            "mission_orchestrator: revoked {n} credential(s) for mission {mission_id} at close"
+        ),
+        Err(e) => eprintln!(
+            "mission_orchestrator: could NOT revoke credentials for mission {mission_id}: {e} \
+             — they expire on their own within 24 h"
+        ),
+    }
+}

crates/cm-api/src/phase_runner.rs

@@ -2860,7 +2860,7 @@ async fn skip_unreachable_phases(pool: &PgPool) -> Result<(), String> {
 }
 
 async fn close_finished_missions(pool: &PgPool) -> Result<(), String> {
-    sqlx::query(
+    let closed: Vec<Uuid> = sqlx::query_scalar(
         "UPDATE missions m
             SET status =
               CASE
@@ -2899,11 +2899,16 @@ async fn close_finished_missions(pool: &PgPool) -> Result<(), String> {
                      AND a.phase_id = mp.id
                      AND a.kind = 'code_diff'
                 )
-            )",
+            )
+          RETURNING m.id",
     )
-    .execute(pool)
+    .fetch_all(pool)
     .await
     .map_err(|e| format!("close finished missions: {e}"))?;
+    // A closed mission's credentials end with it.
+    for mission_id in closed {
+        crate::mission_orchestrator::revoke_mission_credentials(pool, mission_id).await;
+    }
     Ok(())
 }
 

crates/cm-api/src/routes/missions.rs

@@ -1494,6 +1494,11 @@ pub async fn set_status(
 
     cm_db::repo::missions::set_status(&state.pool, id, user.workspace_id.as_uuid(), &body.status)
         .await?;
+    // An operator's stop is a terminal transition too, and the runner's
+    // close never sees it: revoke here as well.
+    if matches!(body.status.as_str(), "completed" | "failed" | "cancelled") {
+        crate::mission_orchestrator::revoke_mission_credentials(&state.pool, id).await;
+    }
 
     let mission = cm_db::repo::missions::get(&state.pool, id, user.workspace_id.as_uuid())
         .await?

crates/cm-auth/src/service.rs

@@ -376,6 +376,47 @@ impl AuthService {
         Ok(token.secret().to_string())
     }
 
+    /// As [`Self::mint_scoped`], bound to a mission: the row carries
+    /// `mission_id`, and [`Self::revoke_mission_sessions`] deletes it when
+    /// the mission ends. A 24 h TTL is the backstop, not the lifetime.
+    pub async fn mint_scoped_for_mission(
+        &self,
+        user_id: UserId,
+        scope: &str,
+        ttl: Duration,
+        mission_id: uuid::Uuid,
+    ) -> Result<String, AuthError> {
+        if scope == SCOPE_FULL {
+            return Err(AuthError::Unauthenticated);
+        }
+        let token = SessionToken::generate();
+        sqlx::query(
+            "INSERT INTO auth_sessions (token_hash, user_id, expires_at, scope, mission_id)
+             VALUES ($1, $2, $3, $4, $5)",
+        )
+        .bind(hash_token(token.secret()))
+        .bind(user_id.as_uuid())
+        .bind(OffsetDateTime::now_utc() + ttl)
+        .bind(scope)
+        .bind(mission_id)
+        .execute(&self.pool)
+        .await?;
+        Ok(token.secret().to_string())
+    }
+
+    /// Revoke every session minted for a mission. Returns how many there
+    /// were; zero is the normal case for a mission that had no door.
+    pub async fn revoke_mission_sessions(
+        &self,
+        mission_id: uuid::Uuid,
+    ) -> Result<u64, AuthError> {
+        let done = sqlx::query("DELETE FROM auth_sessions WHERE mission_id = $1")
+            .bind(mission_id)
+            .execute(&self.pool)
+            .await?;
+        Ok(done.rows_affected())
+    }
+
     /// Mint a long-lived opaque session for an internal service caller
     /// (e.g. the per-team ZeroClaw runtime calling back into the MCP door).
     /// Returns the plaintext token — the caller is responsible for handing

crates/cm-auth/tests/mission_sessions.rs

@@ -0,0 +1,97 @@
+//! A credential minted for a mission ends with the mission.
+//!
+//! The skills-door token is scoped and short-lived, and before 2026-09-20 it
+//! was also un-revocable: nothing tied it to the mission, so a mission that
+//! finished in minutes left a live token in its container for the rest of
+//! the 24 h TTL. These tests pin the two halves — mint-for-mission
+//! authenticates like any scoped token, and revoke-for-mission kills it.
+
+use cm_auth::{bootstrap_owner, AuthService, SCOPE_SKILLS_READ};
+
+async fn owner(pool: &sqlx::PgPool) -> cm_domain::User {
+    bootstrap_owner(pool, "Acme", "[email protected]", "pw-123456", 0)
+        .await
+        .unwrap();
+    cm_db::repo::users::find_by_email(pool, "[email protected]")
+        .await
+        .unwrap()
+}
+
+async fn mission(pool: &sqlx::PgPool, ws: uuid::Uuid) -> uuid::Uuid {
+    let id = uuid::Uuid::now_v7();
+    sqlx::query(
+        "INSERT INTO missions (id, workspace_id, title, template_kind, status)
+         VALUES ($1, $2, 'm', 'research_only', 'running')",
+    )
+    .bind(id)
+    .bind(ws)
+    .execute(pool)
+    .await
+    .unwrap();
+    id
+}
+
+#[tokio::test]
+async fn a_mission_token_works_until_the_mission_is_closed_and_not_after() {
+    let pool = cm_testkit::test_pool().await;
+    let user = owner(&pool).await;
+    let auth = AuthService::new(pool.clone());
+    let m = mission(&pool, user.workspace_id.as_uuid()).await;
+
+    let token = auth
+        .mint_scoped_for_mission(
+            user.id,
+            SCOPE_SKILLS_READ,
+            time::Duration::hours(24),
+            m,
+        )
+        .await
+        .unwrap();
+    // Positive control: the token is a real, scoped credential.
+    auth.authenticate_scoped(&token, SCOPE_SKILLS_READ)
+        .await
+        .expect("a freshly minted mission token authenticates for its scope");
+    assert!(
+        auth.authenticate(&token).await.is_err(),
+        "a skills token must not pass as a full session"
+    );
+
+    // Revocation: exactly this mission's rows, and the token is dead after.
+    let revoked = auth.revoke_mission_sessions(m).await.unwrap();
+    assert_eq!(revoked, 1);
+    assert!(
+        auth.authenticate_scoped(&token, SCOPE_SKILLS_READ).await.is_err(),
+        "a revoked mission token must not authenticate"
+    );
+    assert_eq!(auth.revoke_mission_sessions(m).await.unwrap(), 0);
+}
+
+#[tokio::test]
+async fn revoking_one_mission_leaves_another_missions_token_alone() {
+    let pool = cm_testkit::test_pool().await;
+    let user = owner(&pool).await;
+    let auth = AuthService::new(pool.clone());
+    let a = mission(&pool, user.workspace_id.as_uuid()).await;
+    let b = mission(&pool, user.workspace_id.as_uuid()).await;
+    let ta = auth
+        .mint_scoped_for_mission(user.id, SCOPE_SKILLS_READ, time::Duration::hours(1), a)
+        .await
+        .unwrap();
+    let tb = auth
+        .mint_scoped_for_mission(user.id, SCOPE_SKILLS_READ, time::Duration::hours(1), b)
+        .await
+        .unwrap();
+    assert_eq!(auth.revoke_mission_sessions(a).await.unwrap(), 1);
+    assert!(auth.authenticate_scoped(&ta, SCOPE_SKILLS_READ).await.is_err());
+    auth.authenticate_scoped(&tb, SCOPE_SKILLS_READ)
+        .await
+        .expect("the other mission's token is untouched");
+
+    // Purging a mission takes its sessions with it (ON DELETE CASCADE).
+    sqlx::query("DELETE FROM missions WHERE id = $1")
+        .bind(b)
+        .execute(&pool)
+        .await
+        .unwrap();
+    assert!(auth.authenticate_scoped(&tb, SCOPE_SKILLS_READ).await.is_err());
+}