Add daemon restart feature from settings (#18)

* Add daemon restart feature from settings

This adds the ability to restart a connected daemon from the settings page.
The feature includes:

- Backend: RestartDaemon command added to DaemonCommand enum
- Backend: New POST /api/v1/mesh/daemons/{id}/restart endpoint
- Backend: Daemon gracefully shuts down tasks and exits with code 42
  (can be used by process managers like systemd to detect restart requests)
- Frontend: restartDaemon() API function
- Frontend: Restart button in Connected Daemons section of settings
- Frontend: Confirmation dialog before restart to prevent accidental restarts

When a daemon receives the restart command, it:
1. Gracefully shuts down all running Claude processes (5s timeout)
2. Exits with code 42 to signal restart requested
3. The daemon can be restarted by a process manager or manually

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

7 files changed, 216 insertions, 11 deletions

diff --git a/makima/frontend/src/lib/api.ts b/makima/frontend/src/lib/api.ts
index 86ff06c..efa72a2 100644
--- a/makima/frontend/src/lib/api.ts
+++ b/makima/frontend/src/lib/api.ts
@@ -1087,6 +1087,29 @@ export async function getDaemon(id: string): Promise<Daemon> {
   return res.json();
 }
 
+/** Response from the restart daemon endpoint */
+export interface RestartDaemonResponse {
+  success: boolean;
+  daemonId: string;
+  message: string;
+}
+
+/**
+ * Restart a connected daemon.
+ * Sends a restart command to the daemon, which will gracefully terminate
+ * and restart. Any running tasks will be interrupted.
+ */
+export async function restartDaemon(id: string): Promise<RestartDaemonResponse> {
+  const res = await authFetch(`${API_BASE}/api/v1/mesh/daemons/${id}/restart`, {
+    method: "POST",
+  });
+  if (!res.ok) {
+    const errorData = await res.json().catch(() => ({}));
+    throw new Error(errorData.message || `Failed to restart daemon: ${res.statusText}`);
+  }
+  return res.json();
+}
+
 // =============================================================================
 // Mesh Chat Types for Task Orchestration
 // =============================================================================
diff --git a/makima/frontend/src/routes/settings.tsx b/makima/frontend/src/routes/settings.tsx
index d3f4c1b..b93ecbc 100644
--- a/makima/frontend/src/routes/settings.tsx
+++ b/makima/frontend/src/routes/settings.tsx
@@ -11,6 +11,7 @@ import {
   changeEmail,
   deleteAccount,
   listDaemons,
+  restartDaemon,
   listRepositoryHistory,
   deleteRepositoryHistory,
   type ApiKeyInfo,
@@ -306,6 +307,8 @@ export default function SettingsPage() {
   const [daemons, setDaemons] = useState<Daemon[]>([]);
   const [daemonsLoading, setDaemonsLoading] = useState(true);
   const [daemonsError, setDaemonsError] = useState<string | null>(null);
+  const [restartingDaemonId, setRestartingDaemonId] = useState<string | null>(null);
+  const [restartConfirmDaemonId, setRestartConfirmDaemonId] = useState<string | null>(null);
 
   // Repository history state
   const [repoHistory, setRepoHistory] = useState<RepositoryHistoryEntry[]>([]);
@@ -376,6 +379,23 @@ export default function SettingsPage() {
     }
   };
 
+  const handleRestartDaemon = async (id: string) => {
+    try {
+      setRestartingDaemonId(id);
+      setDaemonsError(null);
+      await restartDaemon(id);
+      // Daemon will restart, so refresh the list after a short delay
+      setTimeout(() => {
+        loadDaemons();
+      }, 2000);
+    } catch (err) {
+      setDaemonsError(err instanceof Error ? err.message : "Failed to restart daemon");
+    } finally {
+      setRestartingDaemonId(null);
+      setRestartConfirmDaemonId(null);
+    }
+  };
+
   const handleCreate = async () => {
     try {
       setActionLoading(true);
@@ -687,17 +707,19 @@ export default function SettingsPage() {
                         <span className="font-mono text-xs text-[#9bc3ff]">
                           {daemon.hostname || "Unknown Host"}
                         </span>
-                        <span
-                          className={`text-[10px] font-mono uppercase px-2 py-0.5 border ${
-                            daemon.status === "connected"
-                              ? "text-green-400 border-green-700/50 bg-green-900/20"
-                              : daemon.status === "unhealthy"
-                              ? "text-yellow-400 border-yellow-700/50 bg-yellow-900/20"
-                              : "text-[#8899aa] border-[rgba(117,170,252,0.25)]"
-                          }`}
-                        >
-                          {daemon.status}
-                        </span>
+                        <div className="flex items-center gap-2">
+                          <span
+                            className={`text-[10px] font-mono uppercase px-2 py-0.5 border ${
+                              daemon.status === "connected"
+                                ? "text-green-400 border-green-700/50 bg-green-900/20"
+                                : daemon.status === "unhealthy"
+                                ? "text-yellow-400 border-yellow-700/50 bg-yellow-900/20"
+                                : "text-[#8899aa] border-[rgba(117,170,252,0.25)]"
+                            }`}
+                          >
+                            {daemon.status}
+                          </span>
+                        </div>
                       </div>
                       <div className="font-mono text-[10px] text-[#7788aa] space-y-1">
                         <div className="flex justify-between">
@@ -721,6 +743,41 @@ export default function SettingsPage() {
                           </div>
                         )}
                       </div>
+                      {/* Restart Section */}
+                      {daemon.status === "connected" && (
+                        <div className="mt-3 pt-2 border-t border-[rgba(117,170,252,0.1)]">
+                          {restartConfirmDaemonId === daemon.id ? (
+                            <div className="flex items-center justify-between gap-2">
+                              <span className="text-[10px] font-mono text-yellow-400">
+                                Restart daemon? Running tasks will be interrupted.
+                              </span>
+                              <div className="flex gap-2">
+                                <button
+                                  onClick={() => setRestartConfirmDaemonId(null)}
+                                  className="text-[10px] font-mono text-[#7788aa] hover:text-[#9bc3ff] px-2 py-1"
+                                  disabled={restartingDaemonId === daemon.id}
+                                >
+                                  Cancel
+                                </button>
+                                <button
+                                  onClick={() => handleRestartDaemon(daemon.id)}
+                                  disabled={restartingDaemonId === daemon.id}
+                                  className="text-[10px] font-mono text-red-400 hover:text-red-300 px-2 py-1 border border-red-700/50 bg-red-900/20 disabled:opacity-50"
+                                >
+                                  {restartingDaemonId === daemon.id ? "Restarting..." : "Confirm"}
+                                </button>
+                              </div>
+                            </div>
+                          ) : (
+                            <button
+                              onClick={() => setRestartConfirmDaemonId(daemon.id)}
+                              className="text-[10px] font-mono text-[#75aafc] hover:text-[#9bc3ff]"
+                            >
+                              ⟳ Restart Daemon
+                            </button>
+                          )}
+                        </div>
+                      )}
                     </div>
                   ))}
                 </div>
diff --git a/makima/src/daemon/task/manager.rs b/makima/src/daemon/task/manager.rs
index 5eed0e8..a3e4732 100644
--- a/makima/src/daemon/task/manager.rs
+++ b/makima/src/daemon/task/manager.rs
@@ -1663,6 +1663,15 @@ impl TaskManager {
                 tracing::info!(source_dir = ?source_dir, "Inheriting git config");
                 self.handle_inherit_git_config(source_dir).await?;
             }
+            DaemonCommand::RestartDaemon => {
+                tracing::info!("Received restart command from server, initiating daemon restart...");
+                // Shutdown all running tasks gracefully
+                self.shutdown_all_processes(std::time::Duration::from_secs(5)).await;
+                // Exit the process - the daemon should be restarted by a process manager
+                // or the user can restart it manually
+                tracing::info!("Daemon restart: exiting process with code 42 (restart requested)");
+                std::process::exit(42);
+            }
         }
         Ok(())
     }
diff --git a/makima/src/daemon/ws/protocol.rs b/makima/src/daemon/ws/protocol.rs
index d0bcc19..3b02b53 100644
--- a/makima/src/daemon/ws/protocol.rs
+++ b/makima/src/daemon/ws/protocol.rs
@@ -624,6 +624,9 @@ pub enum DaemonCommand {
         code: String,
         message: String,
     },
+
+    /// Restart the daemon process.
+    RestartDaemon,
 }
 
 impl DaemonMessage {
diff --git a/makima/src/server/handlers/mesh.rs b/makima/src/server/handlers/mesh.rs
index 99c3d9d..53e1587 100644
--- a/makima/src/server/handlers/mesh.rs
+++ b/makima/src/server/handlers/mesh.rs
@@ -3561,3 +3561,112 @@ pub async fn branch_task(
     )
         .into_response()
 }
+
+// =============================================================================
+// Daemon Management
+// =============================================================================
+
+/// Response for restart daemon request.
+#[derive(Debug, serde::Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct RestartDaemonResponse {
+    /// Whether the restart command was sent successfully.
+    pub success: bool,
+    /// The daemon ID that received the restart command.
+    pub daemon_id: Uuid,
+    /// Message describing the result.
+    pub message: String,
+}
+
+/// Restart a daemon by ID (requires authentication).
+///
+/// Sends a restart command to the specified daemon, which will cause it to
+/// gracefully terminate and restart. Any running tasks will be interrupted.
+#[utoipa::path(
+    post,
+    path = "/api/v1/mesh/daemons/{id}/restart",
+    params(
+        ("id" = Uuid, Path, description = "Daemon ID")
+    ),
+    responses(
+        (status = 200, description = "Restart command sent", body = RestartDaemonResponse),
+        (status = 401, description = "Unauthorized", body = ApiError),
+        (status = 404, description = "Daemon not found or not connected", body = ApiError),
+        (status = 503, description = "Database not configured", body = ApiError),
+        (status = 500, description = "Internal server error", body = ApiError),
+    ),
+    security(
+        ("bearer_auth" = []),
+        ("api_key" = [])
+    ),
+    tag = "Mesh"
+)]
+pub async fn restart_daemon(
+    State(state): State<SharedState>,
+    Authenticated(auth): Authenticated,
+    Path(id): Path<Uuid>,
+) -> impl IntoResponse {
+    let Some(ref pool) = state.db_pool else {
+        return (
+            StatusCode::SERVICE_UNAVAILABLE,
+            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
+        )
+            .into_response();
+    };
+
+    // Verify the daemon exists and belongs to this owner
+    match repository::get_daemon_for_owner(pool, id, auth.owner_id).await {
+        Ok(Some(_)) => {}
+        Ok(None) => {
+            return (
+                StatusCode::NOT_FOUND,
+                Json(ApiError::new("NOT_FOUND", "Daemon not found")),
+            )
+                .into_response();
+        }
+        Err(e) => {
+            tracing::error!("Failed to get daemon {}: {}", id, e);
+            return (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ApiError::new("DB_ERROR", e.to_string())),
+            )
+                .into_response();
+        }
+    }
+
+    // Check if daemon is connected
+    if !state.is_daemon_connected(id) {
+        return (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new(
+                "DAEMON_NOT_CONNECTED",
+                "Daemon is not currently connected",
+            )),
+        )
+            .into_response();
+    }
+
+    // Send restart command to daemon
+    let command = DaemonCommand::RestartDaemon;
+    if let Err(e) = state.send_daemon_command(id, command).await {
+        tracing::error!("Failed to send restart command to daemon {}: {}", id, e);
+        return (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            Json(ApiError::new("DAEMON_ERROR", e)),
+        )
+            .into_response();
+    }
+
+    tracing::info!(
+        daemon_id = %id,
+        owner_id = %auth.owner_id,
+        "Restart command sent to daemon"
+    );
+
+    Json(RestartDaemonResponse {
+        success: true,
+        daemon_id: id,
+        message: "Restart command sent. The daemon will restart shortly.".to_string(),
+    })
+    .into_response()
+}
diff --git a/makima/src/server/mod.rs b/makima/src/server/mod.rs
index d575997..0bc1b92 100644
--- a/makima/src/server/mod.rs
+++ b/makima/src/server/mod.rs
@@ -93,6 +93,7 @@ pub fn make_router(state: SharedState) -> Router {
         .route("/mesh/daemons", get(mesh::list_daemons))
         .route("/mesh/daemons/directories", get(mesh::get_daemon_directories))
         .route("/mesh/daemons/{id}", get(mesh::get_daemon))
+        .route("/mesh/daemons/{id}/restart", post(mesh::restart_daemon))
         // Merge endpoints for orchestrators
         .route("/mesh/tasks/{id}/branches", get(mesh_merge::list_branches))
         .route("/mesh/tasks/{id}/merge/start", post(mesh_merge::merge_start))
diff --git a/makima/src/server/state.rs b/makima/src/server/state.rs
index 38aadf5..28d65d0 100644
--- a/makima/src/server/state.rs
+++ b/makima/src/server/state.rs
@@ -435,6 +435,9 @@ pub enum DaemonCommand {
 
     /// Error response
     Error { code: String, message: String },
+
+    /// Restart the daemon process
+    RestartDaemon,
 }
 
 /// Active daemon connection info stored in state.