CLAUDE.md

@@ -28,12 +28,14 @@ Three global broadcast buses — **never add a fourth without checking these fir
 | Bus | Cap | Events | File |
 |-----|-----|--------|------|
 | `ChatEventBus` | 256 | user message, assistant response, compaction done | `core-api/src/bus.rs` |
-| `SystemEventBus` | 64 | provider (un)registered, config key updated, job completed, session cancelled, **user created/deleted/mounts-changed** | `core-api/src/system_bus.rs` |
+| `SystemEventBus` | 64 | provider (un)registered, config key updated, job completed, session cancelled, **user created/deleted/active-changed/mounts-changed** | `core-api/src/system_bus.rs` |
 | `GlobalEvent` (per-user) | 512 | all `ServerEvent` variants → WS clients + inbox lifecycle | `core-api/src/events.rs` |
 
 Plus internal `mpsc` queues: per-source `SourceInbox` (message serialization) and a central `notify` queue (background agents → user).
 
-**The user-lifecycle reconciler** is the worked example of the rule. Creating a user, deleting one, or changing a shared-folder/project membership all need Docker work (provision, tear down, recreate with new bind mounts). None of the endpoints that make those changes touches `ContainerManager`: each announces `SystemEvent::User{Created,Deleted,MountsChanged}` **after** its DB write, and one subscriber — `skald::wiring::spawn_user_lifecycle`, spawned post-construction because it reacts through `Skald`'s own accessors, holding only a `Weak` — does the reacting, sequentially and best-effort. The payoff is that a *future* endpoint granting membership cannot forget to remount, because remounting was never its job. Reactions never block the HTTP response, and a failure settles at the user's next login or at boot reconciliation.
+**The user-lifecycle reconciler** is the worked example of the rule. Creating a user, deleting one, deactivating one, or changing a shared-folder/project membership all need Docker work (provision, tear down, stop, recreate with new bind mounts). None of the endpoints that make those changes touches `ContainerManager`: each announces `SystemEvent::User{Created,Deleted,ActiveChanged,MountsChanged}` **after** its DB write, and one subscriber — `skald::wiring::spawn_user_lifecycle`, spawned post-construction because it reacts through `Skald`'s own accessors, holding only a `Weak` — does the reacting, sequentially and best-effort. The payoff is that a *future* endpoint granting membership cannot forget to remount, because remounting was never its job. Reactions never block the HTTP response, and a failure settles at the user's next login or at boot reconciliation.
+
+**Where the bus stops: reconciliation rides it, authorization does not.** `SystemEventBus` is a lossy 64-slot broadcast whose contract is *"best-effort, settles at the next login"* — right for a stale mount, wrong for a revocation, where "settles later" *is* the failure. So deactivating or deleting a user splits in two: `Skald::revoke_user_runtime` runs **synchronously in the handler, before it responds** (revoke every session → evict + cancel the `UserContext` → `UserManager::lock`, in that order, so nothing is left querying a pool we then close and the DEK leaves RAM per §9), while only the container half — stop or remove — rides the bus. Before this, `active = 0` blocked the *next* login but left live sessions working: `login` checks the flag, `require_auth` only maps token → id. **Never put an access revocation on a bus.**
 
 **Before you add a direct function call or a new import between two components, stop and ask:** is one component producing data another needs? If yes, add a variant to an existing bus and spawn a subscriber. Don't call `some_manager.log_thing(...)` from the producer — emit a `ThingHappened` event on `SystemEventBus` and let the manager subscribe.
 
@@ -55,7 +57,7 @@ Domain words are allowed only in seed data, preset labels, UI copy and positioni
 
 ### Current state
 
-`UserManager` (§11) is now **consumed**. Login exists (`crates/skald-core/src/auth/`: `SessionStore` + the `guard.rs` deny-by-default middleware; first admin created by `skald-setup`), and the per-user owner-bound runtime is `UserContext` (`crates/skald-core/src/skald/user_context.rs`) — resolved by `Skald::user_context` / the frontend's `require_context`, keyed off `UserManager::pool_of`. The frontend owner call-sites (WS, sessions, inbox, approval-pending, projects, uploads, run-context, **cron**) route through the per-user pool; dev/stats read `llm_requests` — a *registry* table — from `system.db`, which is correct. The "owner-without-a-user" question resolved to **there isn't one**: every owner content belongs to a logged-in user (the admin included). The global owner-bound bundles (`Conversation`/`Tasks`: the "ownerless" `ChatSessionManager`, `ChatHub`, cron `TaskManager`, `TicManager`) are still constructed but **inert** — their loops never spawn and nothing consumes their accessors; removing them is pending follow-on work (kept for now because `RunContextManager` shares the `Conversation` bundle and *is* used, being registry-backed). See blueprint §19.
+`UserManager` (§11) is now **consumed**. Login exists (`crates/skald-core/src/auth/mod.rs`: `SessionStore` — `login`/`user_of`/`logout` plus `revoke_user`, the admin-side "drop every session of this user" used by `Skald::revoke_user_runtime`; the deny-by-default middleware is `src/frontend/api/guard.rs`, whose `require_auth` maps token → id and does **not** re-read the row, which is exactly why revocation must be pushed rather than polled; first admin created by `skald-setup`), and the per-user owner-bound runtime is `UserContext` (`crates/skald-core/src/skald/user_context.rs`) — resolved by `Skald::user_context` / the frontend's `require_context`, keyed off `UserManager::pool_of`, and carrying its **own `CancellationToken`** (a child of the instance one) so a single user's cron/hub/MCP loops can be stopped without touching anyone else's. The frontend owner call-sites (WS, sessions, inbox, approval-pending, projects, uploads, run-context, **cron**) route through the per-user pool; dev/stats read `llm_requests` — a *registry* table — from `system.db`, which is correct. The "owner-without-a-user" question resolved to **there isn't one**: every owner content belongs to a logged-in user (the admin included). The global owner-bound bundles (`Conversation`/`Tasks`: the "ownerless" `ChatSessionManager`, `ChatHub`, cron `TaskManager`, `TicManager`) are still constructed but **inert** — their loops never spawn and nothing consumes their accessors; removing them is pending follow-on work (kept for now because `RunContextManager` shares the `Conversation` bundle and *is* used, being registry-backed). See blueprint §19.
 
 Direction of travel, decided but not yet executed: strip the **power-user surface** (self-rewriting, arbitrary shell, dev-agent suite, ticket system) and move to a **binary-first** layout — the app is built once and run from a compiled binary, not executed from its own source tree.
 
@@ -347,7 +349,11 @@ All extend `LightElement` from `web/lib/base.js` (Lit). `ChatSession` (`web/lib/
 
 **Role-driven interface** (§0.1 — data, not enums): `roles.attrs` JSON may carry `"ui_mode": "simple"`. `/api/auth/me` resolves it via `RoleAttrs` (`admin` is always `full`) and the sidebar renders chat + inbox only for simple-mode members; the role editor exposes it as an "Interface" select. Hiding links is never access control — routes stay capability-gated server-side. `MeResponse` also carries `locale`, `default_locale` and `encrypted`.
 
-**Security-group picker (per-session, runtime, role-gated).** A **security-group** is a *permission bundle only* — a `tool_permission_groups` id, driving tool visibility/approval — **not** a "mode" (no system-context injection; the `RunContext.system_prompt` substrate exists but is unused by the picker). The role carries the user's **allowed set** (default `permission_group` + `attrs.permission_groups`, §0.1); a new non-project session inherits the role's default group (`sessions.rs::create` → `role_default_run_context`). The chat surface switches it **at runtime like the model pill**: `copilot.js` renders a shield pill (hidden when ≤1 group) fed by `GET /api/my/security-groups` (the caller's role set, joined with group names; `admin` → all); selecting one sends the WS control message `{type:"select_security_group", group}` (`chat-session.js::_selectGroup`, twin of `select_client`). The server (`ws.rs::handle_select_security_group_msg`) validates against the role, persists it on `chat_sessions.run_context`, updates the live handler, and **broadcasts `ServerEvent::SecurityGroupSelected`** so every open tab re-syncs (the initial state is sent on WS connect). **Enforcement is server-side** via the shared `run_context::validate_run_context_for_role` (used by both the WS path and the REST `set_session_run_context`): a non-admin may only pick a group in its role's effective set (else 403), and **every other `RunContext` field** (`system_prompt`, `allow_fs_writes`/`allow_fs_reads`, `working_directory`) is **discarded** — closing an fs-escalation hole; `admin` passes through unchanged. The role editor (`roles-page.js`) sets the default group + an allowed-groups checklist (→ `attrs.permission_groups`) + a **default-assistant** select (→ `attrs.chat_agent`) fed by `GET /api/agents` filtered to `type:chat` minus `project-coordinator` (source-driven); the same exclusion is enforced server-side in the roles API (`validate_chat_agent`).
+**Security-group picker (per-session, runtime, role-gated).** A **security-group** is a *permission bundle only* — a `tool_permission_groups` id, driving tool visibility/approval — **not** a "mode" (no system-context injection; the `RunContext.system_prompt` substrate exists but is unused by the picker). The role carries the user's **allowed set** (default `permission_group` + `attrs.permission_groups`, §0.1); a new non-project session inherits the role's default group (`sessions.rs::create` → `role_default_run_context`). The chat surface switches it **at runtime like the model pill**: `copilot.js` renders a shield pill (hidden when ≤1 group) fed by `GET /api/my/security-groups` (the caller's role set, joined with group names; `admin` → all); selecting one sends the WS control message `{type:"select_security_group", group}` (`chat-session.js::_selectGroup`, twin of `select_client`). The server (`ws.rs::handle_select_security_group_msg`) validates against the role, persists it on `chat_sessions.run_context`, updates the live handler, and **broadcasts `ServerEvent::SecurityGroupSelected`** so every open tab re-syncs (the initial state is sent on WS connect). **Enforcement is server-side** via the shared `run_context::validate_run_context_for_role` (used by both the WS path and the REST `set_session_run_context`): a non-admin may only pick a group in its role's effective set (else 403), and **every other `RunContext` field** (`system_prompt`, `allow_fs_writes`/`allow_fs_reads`, `working_directory`) is **discarded** — closing an fs-escalation hole; `admin` passes through unchanged.
+
+**Selection is gated once; the persisted group is re-checked on every load.** `validate_run_context_for_role` runs at *selection* time, and the result is persisted on `chat_sessions.run_context` — so on its own it let a group survive the role that granted it, indefinitely and across restarts (revoke `ops` from a role, and every session that had already picked it kept running on it). The fix is a second, narrower seam: `run_context::reconcile_group_for_user`, run by `ChatSessionManager::get_or_create_handler` on **every** handler build, which treats the stored group as *advisory* and degrades it when the owner's current role no longer allows it. Three properties are load-bearing: (a) it degrades to the **role's default group** (`role_default_group`, the same seam `sessions.rs` uses for a new session, so start-group and fallback-group cannot drift) — **never to `None`**, because a missing group means the catch-all `default`, whose rules are the fallback tier under every other group, so clearing *widens*; (b) it touches **only** `security_group`, unlike the selection path, so a project session's server-built `project_root`/`system_prompt` survive a permissions edit; (c) on uncertainty (unknown user, unreadable role, DB error) it leaves the stored group alone — guessing could only widen. The liveness half is `Skald::revalidate_security_groups_for_{user,role}`, called **synchronously** from the roles API (`update`) and the users API (role reassignment), which reconciles already-open handlers, persists, and emits `SecurityGroupSelected` so the pill re-syncs. Same rule as revocation: authorization is pushed, never left to the bus.
+
+The role editor (`roles-page.js`) sets the default group + an allowed-groups checklist (→ `attrs.permission_groups`) + a **default-assistant** select (→ `attrs.chat_agent`) fed by `GET /api/agents` filtered to `type:chat` minus `project-coordinator` (source-driven); the same exclusion is enforced server-side in the roles API (`validate_chat_agent`).
 
 | File | Element | Notes |
 | ---- | ------- | ----- |

crates/core-api/src/system_bus.rs

@@ -68,6 +68,18 @@ pub enum SystemEvent {
     UserDeleted {
         user_id: String,
     },
+    /// A user was deactivated (`false`) or reactivated (`true`). Their sandbox is
+    /// stopped or started to match — boot reconciliation keeps a container only for
+    /// *active* users, so this is the running-server equivalent.
+    ///
+    /// Revoking the live runtime (sessions, loops, database key) is **not** on this
+    /// event: it is an authorization invariant and runs synchronously in the handler
+    /// (`Skald::revoke_user_runtime`), because a lossy broadcast is the wrong
+    /// transport for "this person must stop being logged in".
+    UserActiveChanged {
+        user_id: String,
+        active:  bool,
+    },
     /// A user's **mount topology** changed — a shared-folder or project membership
     /// was granted, revoked or re-graded (RO ⇄ RW). Their container must be
     /// recreated against the new mount set, and a live session's filesystem view

crates/skald-core/src/auth/mod.rs

@@ -71,6 +71,39 @@ impl SessionStore {
             .cloned()
     }
 
+    /// Removes **every** session of one user, returning how many were dropped.
+    ///
+    /// The admin half of [`logout`](Self::logout): a deactivated or deleted user
+    /// must stop being authenticated *now*, not at their next request. `login`
+    /// already refuses an inactive user (`verify_credentials` / `open_db` check the
+    /// flag), but `require_auth` only maps token → id and would happily keep serving
+    /// a token minted before the flag flipped.
+    ///
+    /// Sessions only, deliberately: this leaves the pool open, so the caller must
+    /// follow with `UserManager::lock` to get the key out of RAM (§9). Both run
+    /// synchronously on the admin's request — revocation is an invariant, not
+    /// something to reconcile later on a lossy bus.
+    pub fn revoke_user(&self, user_id: &str) -> usize {
+        let mut map = self.sessions.write().expect("sessions map poisoned");
+        let before = map.len();
+        map.retain(|_, id| id != user_id);
+        let removed = before - map.len();
+        if removed > 0 {
+            info!(user = %user_id, sessions = removed, "sessions revoked");
+        }
+        removed
+    }
+
+    /// Records a session without authenticating — tests only, so the revocation
+    /// semantics can be exercised without paying an Argon2id derivation per login.
+    #[cfg(test)]
+    fn insert_session(&self, token: &str, user_id: &str) {
+        self.sessions
+            .write()
+            .expect("sessions map poisoned")
+            .insert(token.to_string(), user_id.to_string());
+    }
+
     /// Removes a single session. The database pool stays open (§9).
     pub fn logout(&self, token: &str) {
         if let Some(user_id) = self
@@ -83,3 +116,59 @@ impl SessionStore {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn temp_db_path(tag: &str) -> String {
+        let mut p = std::env::temp_dir();
+        let nanos = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH).unwrap().as_nanos();
+        p.push(format!("skald-test-{tag}-{}-{nanos}.db", std::process::id()));
+        p.to_string_lossy().into_owned()
+    }
+
+    fn cleanup(path: &str) {
+        for suffix in ["", "-wal", "-shm"] {
+            let _ = std::fs::remove_file(format!("{path}{suffix}"));
+        }
+    }
+
+    async fn store(tag: &str) -> (SessionStore, String) {
+        let path = temp_db_path(tag);
+        let pool = Arc::new(crate::db::init_system_pool(&path).await.unwrap());
+        (SessionStore::new(Arc::new(UserManager::new(pool))), path)
+    }
+
+    /// Deactivating or deleting a user must drop **every** session they hold — one
+    /// browser left logged in is the whole bug — and **only** theirs.
+    #[tokio::test]
+    async fn revoke_user_drops_all_of_one_users_sessions_and_nobody_elses() {
+        let (store, path) = store("revoke").await;
+        store.insert_session("t-laptop", "u-1");
+        store.insert_session("t-phone",  "u-1");
+        store.insert_session("t-other",  "u-2");
+
+        assert_eq!(store.revoke_user("u-1"), 2);
+        assert_eq!(store.user_of("t-laptop"), None);
+        assert_eq!(store.user_of("t-phone"),  None);
+        assert_eq!(store.user_of("t-other").as_deref(), Some("u-2"),
+            "revoking one user must not log out the rest of the household");
+
+        cleanup(&path);
+    }
+
+    /// Idempotent: revoking a user with nothing live is a no-op, not an error — the
+    /// admin path calls it unconditionally.
+    #[tokio::test]
+    async fn revoke_user_is_a_no_op_when_nothing_is_live() {
+        let (store, path) = store("revoke-empty").await;
+        store.insert_session("t-other", "u-2");
+
+        assert_eq!(store.revoke_user("u-1"), 0);
+        assert_eq!(store.user_of("t-other").as_deref(), Some("u-2"));
+
+        cleanup(&path);
+    }
+}

crates/skald-core/src/run_context/mod.rs

@@ -140,6 +140,88 @@ pub async fn validate_run_context_for_role(
     }
 }
 
+/// The catch-all permission group. A `RunContext` with no `security_group` resolves
+/// here, and its rules are the fallback tier under *every* other group — so clearing
+/// a group **widens** what a session may do, and is never the safe direction.
+pub const DEFAULT_GROUP_ID: &str = "default";
+
+/// The security group a session gets from its owner's role: `roles.permission_group`,
+/// or `None` when that is unset or already the catch-all (nothing to pin).
+pub async fn role_default_group(registry_pool: &SqlitePool, user_id: &str) -> Option<String> {
+    let user  = crate::db::users::get(registry_pool, user_id).await.ok()??;
+    let role  = crate::db::roles::get(registry_pool, &user.role_id).await.ok()??;
+    let group = role.permission_group;
+    (!group.is_empty() && group != DEFAULT_GROUP_ID).then_some(group)
+}
+
+/// A run-context for a **new** session carrying nothing but the role's default group,
+/// so a restricted role starts scoped instead of on the catch-all.
+pub async fn role_default_run_context(
+    registry_pool: &SqlitePool,
+    user_id:       &str,
+) -> Option<RunContext> {
+    role_default_group(registry_pool, user_id)
+        .await
+        .map(|g| RunContext::with_security_group(Some(g)))
+}
+
+/// Re-checks a **persisted** run-context's security group against the owner's
+/// *current* role, degrading it to the role default when the role no longer allows it.
+///
+/// This is the counterpart of [`validate_run_context_for_role`], which gates a group
+/// at *selection* time. The selected group is then persisted on `chat_sessions.
+/// run_context` and was replayed verbatim on every later load — so revoking a group
+/// from a role, or moving a user to a stricter role, left every session that already
+/// had it running with it, indefinitely and across restarts. Running every load
+/// through here makes the persisted value advisory rather than authoritative.
+///
+/// Deliberately **narrow**: only `security_group` is touched. A project session's
+/// server-built context (`project_root`, `system_prompt`, fs grants) must survive
+/// intact — unlike the selection path, which discards those because they came from
+/// a client.
+///
+/// Conservative on uncertainty: with no group, an `admin` owner, or a role that
+/// cannot be read, the context is returned unchanged. Guessing on a transient DB
+/// error could only widen the session, which is the one outcome worth avoiding.
+pub async fn reconcile_group_for_user(
+    registry_pool: &SqlitePool,
+    user_id:       &str,
+    rc:            Option<RunContext>,
+) -> Option<RunContext> {
+    let mut rc = rc?;
+    let Some(group) = rc.tool_group_id().map(str::to_string) else { return Some(rc) };
+
+    let role_id = match crate::db::users::get(registry_pool, user_id).await {
+        Ok(Some(u)) => u.role_id,
+        other => {
+            tracing::warn!(user = %user_id, group = %group, missing = other.is_ok(),
+                "run_context: cannot resolve role, leaving the persisted security group in place");
+            return Some(rc);
+        }
+    };
+    if role_id == crate::db::roles::ADMIN_ROLE_ID {
+        return Some(rc);
+    }
+    match crate::db::roles::role_allows_group(registry_pool, &role_id, &group).await {
+        Ok(true) => return Some(rc),
+        Ok(false) => {}
+        Err(e) => {
+            tracing::warn!(user = %user_id, group = %group, error = %e,
+                "run_context: group check failed, leaving the persisted security group in place");
+            return Some(rc);
+        }
+    }
+
+    let replacement = role_default_group(registry_pool, user_id).await;
+    info!(
+        user = %user_id, role = %role_id, revoked = %group,
+        now = replacement.as_deref().unwrap_or(DEFAULT_GROUP_ID),
+        "run_context: security group no longer allowed by the role, degraded to the role default"
+    );
+    rc.security_group = replacement;
+    Some(rc)
+}
+
 pub struct RunContextManager {
     db:       Arc<SqlitePool>,
     approval: Arc<ApprovalManager>,
@@ -370,6 +452,100 @@ mod tests {
         std::fs::remove_dir_all(&wd).ok();
     }
 
+    /// A registry with one role and one member of it. No crypto: the reconcile path
+    /// only reads the directory, never a credential.
+    async fn registry_with(role: &str, default_group: &str, extra_groups: &str) -> SqlitePool {
+        let path = unique_tmp().join("system.db");
+        let pool = crate::db::init_system_pool(path.to_str().unwrap()).await.unwrap();
+        crate::db::roles::insert(&pool, role, "Role", default_group, Some(extra_groups))
+            .await
+            .unwrap();
+        crate::db::users::insert(
+            &pool, "u-1", "ada", None, role,
+            &crate::db::users::Credentials::Cleartext(None),
+        )
+        .await
+        .unwrap();
+        pool
+    }
+
+    /// The regression: a group selected while the role allowed it was replayed from
+    /// `chat_sessions.run_context` forever, so revoking it from the role changed
+    /// nothing for sessions that already had it.
+    #[tokio::test]
+    async fn reconcile_degrades_a_group_the_role_no_longer_allows() {
+        // The role's default is `kid`; `ops` is NOT in its set (it was, once).
+        let pool = registry_with("member", "kid", r#"{"permission_groups":[]}"#).await;
+
+        let rc = RunContext { security_group: Some("ops".into()), ..Default::default() };
+        let got = reconcile_group_for_user(&pool, "u-1", Some(rc)).await.unwrap();
+        assert_eq!(got.tool_group_id(), Some("kid"),
+            "a revoked group must degrade to the role default, never to the catch-all");
+    }
+
+    /// Degrading must not silently widen: clearing to `None` would put a restricted
+    /// user on the catch-all `default` group, whose rules are the fallback tier under
+    /// every other group.
+    #[tokio::test]
+    async fn reconcile_keeps_an_allowed_group_and_preserves_the_rest_of_the_context() {
+        let pool = registry_with("member", "kid", r#"{"permission_groups":["ops"]}"#).await;
+
+        // Still allowed → untouched, including a project session's server-built fields,
+        // which the *selection* path would have stripped.
+        let rc = RunContext {
+            security_group: Some("ops".into()),
+            project_root:   Some("projects/ada/site".into()),
+            system_prompt:  vec!["project brief".into()],
+            ..Default::default()
+        };
+        let got = reconcile_group_for_user(&pool, "u-1", Some(rc)).await.unwrap();
+        assert_eq!(got.tool_group_id(), Some("ops"));
+        assert_eq!(got.project_root.as_deref(), Some("projects/ada/site"));
+        assert_eq!(got.system_prompt, vec!["project brief".to_string()]);
+    }
+
+    /// A degrade must keep the rest of the context too — losing `project_root` would
+    /// break a project chat as a side effect of a permissions edit.
+    #[tokio::test]
+    async fn reconcile_degrade_preserves_project_fields() {
+        let pool = registry_with("member", "kid", r#"{"permission_groups":[]}"#).await;
+
+        let rc = RunContext {
+            security_group: Some("ops".into()),
+            project_root:   Some("projects/ada/site".into()),
+            ..Default::default()
+        };
+        let got = reconcile_group_for_user(&pool, "u-1", Some(rc)).await.unwrap();
+        assert_eq!(got.tool_group_id(), Some("kid"));
+        assert_eq!(got.project_root.as_deref(), Some("projects/ada/site"));
+    }
+
+    /// Uncertainty must never widen: an unknown user leaves the persisted group alone
+    /// rather than falling back to the catch-all.
+    #[tokio::test]
+    async fn reconcile_leaves_the_group_alone_when_the_role_cannot_be_resolved() {
+        let pool = registry_with("member", "kid", r#"{"permission_groups":[]}"#).await;
+
+        let rc = RunContext { security_group: Some("ops".into()), ..Default::default() };
+        let got = reconcile_group_for_user(&pool, "ghost", Some(rc)).await.unwrap();
+        assert_eq!(got.tool_group_id(), Some("ops"));
+    }
+
+    /// `admin` holds every group by construction, so nothing is ever degraded for it.
+    #[tokio::test]
+    async fn reconcile_never_touches_an_admin() {
+        let path = unique_tmp().join("system.db");
+        let pool = crate::db::init_system_pool(path.to_str().unwrap()).await.unwrap();
+        crate::db::users::insert(
+            &pool, "u-admin", "root", None, crate::db::roles::ADMIN_ROLE_ID,
+            &crate::db::users::Credentials::Cleartext(None),
+        ).await.unwrap();
+
+        let rc = RunContext { security_group: Some("anything".into()), ..Default::default() };
+        let got = reconcile_group_for_user(&pool, "u-admin", Some(rc)).await.unwrap();
+        assert_eq!(got.tool_group_id(), Some("anything"));
+    }
+
     #[tokio::test]
     async fn validate_admin_passes_through_untouched() {
         let path = unique_tmp().join("system.db");

crates/skald-core/src/session/manager.rs

@@ -191,7 +191,16 @@ impl ChatSessionManager {
             .await?
             .ok_or_else(|| anyhow::anyhow!("session {session_id} not found"))?;
 
-        let run_context = session.run_context.as_deref().and_then(RunContext::from_db);
+        // The persisted group is **advisory**: re-check it against the owner's current
+        // role, so a group revoked since the session last ran cannot be replayed from
+        // the row. Every load goes through here — restart, re-login, new handler — so
+        // correctness does not depend on anyone having pushed a notification.
+        let run_context = crate::run_context::reconcile_group_for_user(
+            &self.shared_pool,
+            &self.user_id,
+            session.run_context.as_deref().and_then(RunContext::from_db),
+        )
+        .await;
 
         let handler = Arc::new(ChatSessionHandler::new(
             session_id,
@@ -228,4 +237,49 @@ impl ChatSessionManager {
     pub fn refresh_fs(&self, fs: UserFs) {
         self.user_fs.store(fs);
     }
+
+    /// Re-checks every **live** handler's security group against the owner's current
+    /// role, degrading any the role no longer allows (see
+    /// [`crate::run_context::reconcile_group_for_user`]).
+    ///
+    /// [`get_or_create_handler`](Self::get_or_create_handler) already reconciles on
+    /// load, which covers every future session; this covers the sessions that are
+    /// *already* open, whose handler holds its run-context in RAM and would otherwise
+    /// keep the revoked group until the process restarts. Both the row and the live
+    /// handler are updated, so the change survives and the UI reads the truth.
+    ///
+    /// Returns `(source, effective group)` for each session that actually changed —
+    /// the caller broadcasts `SecurityGroupSelected` so open tabs re-sync their pill.
+    pub async fn revalidate_security_groups(&self) -> Vec<(String, String)> {
+        let handlers: Vec<_> = self.active.lock().await
+            .iter().map(|(id, h)| (*id, Arc::clone(h))).collect();
+
+        let mut changed = Vec::new();
+        for (session_id, handler) in handlers {
+            let before = handler.run_context.read().await.clone();
+            let before_group = before.as_ref().and_then(|rc| rc.tool_group_id().map(str::to_string));
+            let after = crate::run_context::reconcile_group_for_user(
+                &self.shared_pool, &self.user_id, before,
+            ).await;
+            let after_group = after.as_ref().and_then(|rc| rc.tool_group_id().map(str::to_string));
+            if before_group == after_group {
+                continue;
+            }
+
+            if let Err(e) = chat_sessions::set_run_context(
+                &self.db, session_id, after.as_ref().map(|rc| rc.to_db()).as_deref(),
+            ).await {
+                // The in-RAM update below still takes effect for this process; the
+                // reconcile on next load would redo the degrade anyway.
+                tracing::warn!(session = session_id, error = %e,
+                    "failed to persist a degraded security group");
+            }
+            handler.set_run_context(after).await;
+            changed.push((
+                handler.source.clone(),
+                after_group.unwrap_or_else(|| crate::run_context::DEFAULT_GROUP_ID.to_string()),
+            ));
+        }
+        changed
+    }
 }

crates/skald-core/src/skald/accessors.rs

@@ -70,6 +70,71 @@ impl Skald {
         self.rt_user_contexts().peek(user_id).await
     }
 
+    /// Revokes a user's live runtime: sessions, owner-bound loops, database key.
+    ///
+    /// Called when a user is **deactivated or deleted**. Writing `active = 0` (or
+    /// deleting the row) only stops the *next* login: `login` checks the flag, but
+    /// `require_auth` maps token → id without re-reading the row, so a session minted
+    /// before the change would keep working, over a pool whose key is still in RAM.
+    ///
+    /// The order is load-bearing:
+    ///
+    /// 1. **Revoke the sessions** — the moment this returns, no token authenticates
+    ///    as this user.
+    /// 2. **Evict the context** — cancels their cron loop, hub and per-user MCP
+    ///    runtime, so nothing is left to query the pool we are about to close.
+    /// 3. **Lock the database** — `close()`s the pool, which invalidates every
+    ///    surviving clone and drops the DEK (§9). The user is opaque again.
+    ///
+    /// Synchronous by design: this is an authorization invariant, not reconciliation,
+    /// so it must not ride the lossy system bus. The Docker half (stop or remove the
+    /// container) *is* reconciliation and does ride it.
+    ///
+    /// Idempotent — a user with no live session and a locked database is a no-op.
+    pub async fn revoke_user_runtime(&self, user_id: &str) {
+        self.sessions().revoke_user(user_id);
+        self.rt_user_contexts().evict(user_id).await;
+        self.rt.users.lock(user_id).await;
+    }
+
+    /// Re-checks a live user's open sessions against their current role, degrading any
+    /// security group the role no longer allows, and tells their open tabs about it.
+    ///
+    /// The durable half of this is in `ChatSessionManager::get_or_create_handler`,
+    /// which reconciles on every load; this is the liveness half, for sessions already
+    /// in RAM. Synchronous, like [`Self::revoke_user_runtime`] and for the same reason:
+    /// narrowing someone's permissions is an authorization change, not reconciliation.
+    ///
+    /// No-op for a user who is not logged in — their next login loads through the
+    /// reconcile anyway.
+    pub async fn revalidate_security_groups_for_user(&self, user_id: &str) {
+        let Some(ctx) = self.user_context_if_live(user_id).await else { return };
+        for (source, group) in ctx.sessions.revalidate_security_groups().await {
+            ctx.chat_hub.emit(core_api::events::GlobalEvent {
+                source:     Some(source),
+                session_id: None,
+                event:      core_api::events::ServerEvent::SecurityGroupSelected { group },
+            });
+        }
+    }
+
+    /// [`Self::revalidate_security_groups_for_user`] for every member of a role —
+    /// called when the role's own group set changes, which can narrow many users at
+    /// once. Members who are not logged in need nothing.
+    pub async fn revalidate_security_groups_for_role(&self, role_id: &str) {
+        let users = match crate::db::users::list(self.db()).await {
+            Ok(u) => u,
+            Err(e) => {
+                tracing::warn!(role = %role_id, error = %e,
+                    "cannot list users to revalidate security groups");
+                return;
+            }
+        };
+        for user in users.into_iter().filter(|u| u.role_id == role_id) {
+            self.revalidate_security_groups_for_user(&user.id).await;
+        }
+    }
+
     /// Applies a shared-folder membership change to a user (blueprint §6 remount).
     ///
     /// A container's bind mounts are fixed at `docker create` time, so the mount set

crates/skald-core/src/skald/user_context.rs

@@ -65,6 +65,11 @@ use super::runtime::Runtime;
 pub struct UserContext {
     pub user_id:       String,
     pub pool:          Arc<SqlitePool>,
+    /// This user's stop signal — a child of the instance shutdown token. Every
+    /// owner-bound loop (cron, hub, per-user MCP) observes it, so cancelling it
+    /// tears down exactly one user's runtime without touching anyone else's.
+    /// Cancelled by [`UserContextRegistry::evict`] on deactivation/deletion.
+    pub shutdown:      CancellationToken,
     /// The owner's filesystem view (home + shared folders + container, §6),
     /// threaded into every `ToolContext` this user's sessions produce. A shared
     /// swappable cell so a shared-folder membership change is applied in place
@@ -181,6 +186,13 @@ impl UserContextFactory {
 
     async fn build(&self, user_id: &str, pool: SqlitePool) -> Result<Arc<UserContext>> {
         let pool = Arc::new(pool);
+        // This user's own stop signal: a **child** of the instance token, so a global
+        // shutdown still stops every user's loops, while cancelling it alone tears
+        // down exactly one user's runtime (deactivation / deletion — see
+        // `UserContextRegistry::evict`). Every owner-bound loop below takes this
+        // token, never the instance one, or a revoked user's cron would keep polling
+        // a closed pool.
+        let user_shutdown = self.shutdown_token.child_token();
         // The owner's filesystem view: private home + shared folders + container.
         // A shared swappable cell — a shared-folder membership change is applied in
         // place while the user is live (§6 remount), not deferred to next login.
@@ -227,7 +239,7 @@ impl UserContextFactory {
         }
         let user_mcp = Arc::new(McpManager::new(
             Arc::clone(&pool),
-            self.shutdown_token.clone(),
+            user_shutdown.clone(),
             "data",
         ));
         // NOTE: per-user MCP elicitation (interactive connector login, §15) is
@@ -335,7 +347,7 @@ impl UserContextFactory {
             Arc::clone(&manager),
             Arc::clone(&approval),
             global_tx.clone(),
-            self.shutdown_token.clone(),
+            user_shutdown.clone(),
             default_agent,
         );
         chat_hub.register("web").await;
@@ -350,14 +362,16 @@ impl UserContextFactory {
         // durable cron job (blueprint §7.2) instead of an interface-tool call.
         manager.loop_runtime().set_task_manager(Arc::clone(&cron));
 
-        // Per-user cron loop. `start()` observes the shutdown token, so it stops on
-        // shutdown; adopting it lets the supervisor also join it. The name is leaked
-        // to satisfy the `&'static str` label — bounded by the (small) user count.
+        // Per-user cron loop. `start()` observes the token, so it stops on a global
+        // shutdown *or* on this user's own revocation; adopting it lets the supervisor
+        // also join it. The name is leaked to satisfy the `&'static str` label —
+        // bounded by the (small) user count.
         let name: &'static str = Box::leak(format!("cron:{user_id}").into_boxed_str());
-        self.supervisor.adopt(name, Arc::clone(&cron).start(self.shutdown_token.clone()));
+        self.supervisor.adopt(name, Arc::clone(&cron).start(user_shutdown.clone()));
 
         Ok(Arc::new(UserContext {
             user_id: user_id.to_string(),
+            shutdown: user_shutdown,
             pool,
             fs,
             event_bus,
@@ -413,6 +427,23 @@ impl UserContextRegistry {
     pub(super) async fn all_live(&self) -> Vec<Arc<UserContext>> {
         self.contexts.lock().await.values().cloned().collect()
     }
+
+    /// Removes a user's context and cancels it — the runtime half of revoking a
+    /// user (deactivation or deletion).
+    ///
+    /// Cancelling the context's own token stops its cron loop, hub and per-user MCP
+    /// runtime; dropping the registry's `Arc` lets the context die once the last
+    /// in-flight borrow releases it, at which point the `docker exec -i` children of
+    /// its MCP servers are reaped by `kill_on_drop`. Locking the pool is **not** done
+    /// here — that is `UserManager`'s job (§11 boundary) and the caller sequences it
+    /// after this, so no loop is left querying a closed pool.
+    ///
+    /// Returns the evicted context, or `None` if the user was not live.
+    pub(super) async fn evict(&self, user_id: &str) -> Option<Arc<UserContext>> {
+        let ctx = self.contexts.lock().await.remove(user_id)?;
+        ctx.shutdown.cancel();
+        Some(ctx)
+    }
 }
 
 // ── UserChannelHandle impl ────────────────────────────────────────────────────

crates/skald-core/src/skald/wiring.rs

@@ -134,6 +134,20 @@ pub(super) fn spawn_user_lifecycle(skald: &Arc<super::Skald>) {
                             "user-lifecycle: failed to remove container");
                     }
                 }
+                // Match boot reconciliation, which keeps a container only for active
+                // users. The user's live runtime is already gone by now — the handler
+                // revoked it synchronously before emitting.
+                SystemEvent::UserActiveChanged { user_id, active } => {
+                    let result = if active {
+                        skald.container().ensure(&user_id).await
+                    } else {
+                        skald.container().stop(&user_id).await
+                    };
+                    if let Err(e) = result {
+                        warn!(user = %user_id, active, error = %e,
+                            "user-lifecycle: failed to apply active-state change to container");
+                    }
+                }
                 SystemEvent::UserMountsChanged { user_id } => {
                     if let Err(e) = skald.refresh_user_mounts(&user_id).await {
                         warn!(user = %user_id, error = %e,

src/frontend/api/roles.rs

@@ -96,6 +96,11 @@ pub async fn update(
         return Err(ApiError::not_found("role not found"));
     }
     let role = roles::get(skald.db(), &id).await?.ok_or_else(|| ApiError::not_found("role not found after update"))?;
+    // The edit may have narrowed the role's group set. Push that onto the members who
+    // are logged in right now — their open sessions hold the previously-selected group
+    // in RAM and would otherwise keep using it. (`delete` needs no equivalent: it
+    // refuses while any user is still assigned.)
+    skald.revalidate_security_groups_for_role(&id).await;
     Ok(Json(role))
 }
 

src/frontend/api/sessions.rs

@@ -10,7 +10,7 @@ use serde::{Deserialize, Serialize};
 use serde_json::{Value, json};
 use sqlx::SqlitePool;
 
-use skald_core::db::{chat_history, chat_llm_tools, chat_sessions, chat_sessions_stack, roles, sources};
+use skald_core::db::{chat_history, chat_llm_tools, chat_sessions, chat_sessions_stack, sources};
 use skald_core::db::chat_sessions_stack::SessionStack;
 use skald_core::run_context::RunContext;
 use std::sync::Arc;
@@ -54,17 +54,16 @@ pub async fn create(
 
 /// The default security-group a new session gets from the owner's role, or `None`
 /// when the role points at the catch-all `default` group (nothing to pin).
+///
+/// Thin wrapper over the core seam, which is also what
+/// [`reconcile_group_for_user`](skald_core::run_context::reconcile_group_for_user)
+/// degrades *to* — so the group a session starts on and the group it falls back to
+/// after a revocation can never drift apart.
 async fn role_default_run_context(
     skald:   &Skald,
     user_id: &str,
 ) -> Result<Option<RunContext>, ApiError> {
-    let Some(user) = skald.users().get(user_id).await? else { return Ok(None) };
-    let Some(role) = roles::get(skald.db(), &user.role_id).await? else { return Ok(None) };
-    let group = role.permission_group;
-    if group.is_empty() || group == "default" {
-        return Ok(None);
-    }
-    Ok(Some(RunContext::with_security_group(Some(group))))
+    Ok(skald_core::run_context::role_default_run_context(skald.db(), user_id).await)
 }
 
 // ── GET /api/web/messages ─────────────────────────────────────────────────────

src/frontend/api/users_mgmt.rs

@@ -142,6 +142,14 @@ pub async fn update(
         body.sex.as_deref(),
         body.notes.as_deref(),
     )?;
+    // Read the current row first: only a real transition should revoke a runtime,
+    // touch a container or re-check permissions, so an ordinary profile edit stays free.
+    let before = skald
+        .users()
+        .get(&id)
+        .await?
+        .ok_or_else(|| ApiError::not_found("no such user"))?;
+    let (was_active, was_role) = (before.active, before.role_id);
     skald_core::db::users::update_profile(
         skald.db(),
         &id,
@@ -164,6 +172,26 @@ pub async fn update(
     )
     .await?;
 
+    // A move to a different role can narrow what this user may select. Their open
+    // sessions hold the old group in RAM and the row holds it on disk, so re-check
+    // both before responding — same reason deactivation is synchronous.
+    if was_role != body.role_id {
+        skald.revalidate_security_groups_for_user(&id).await;
+    }
+
+    if was_active != body.active {
+        // Deactivation has to bite now, not at the user's next request: revoke their
+        // sessions, stop their loops and drop their database key before responding.
+        if !body.active {
+            skald.revoke_user_runtime(&id).await;
+        }
+        // The container half is reconciliation — it rides the bus.
+        skald.system_bus().send(SystemEvent::UserActiveChanged {
+            user_id: id.clone(),
+            active:  body.active,
+        });
+    }
+
     Ok(Json(serde_json::json!({ "ok": true })))
 }
 
@@ -173,6 +201,9 @@ pub async fn delete(
     State(skald): State<Arc<Skald>>,
     Path(id): Path<String>,
 ) -> Result<Json<serde_json::Value>, ApiError> {
+    // Revoke *before* the row goes: a token outliving its user would otherwise
+    // authenticate as an id that no longer exists.
+    skald.revoke_user_runtime(&id).await;
     skald.users().delete_user(&id).await?;
     // The row is gone; the reconciler tears the container down (a missing one is fine).
     skald.system_bus().send(SystemEvent::UserDeleted { user_id: id });