stable hand agent IDs

* fix: use fixed agent ID for hand agents based on hand_id

This ensures triggers and cron jobs continue to work after daemon restart,
as hand agents now have stable IDs instead of generating a new UUID each time.

Changes:
- Add AgentId::from_string() method for deterministic ID generation
- Modify spawn_agent_with_parent() to accept optional fixed_id
- Use hand_id-based fixed ID in activate_hand()

See: #519

* remove: remove serena local config from commit

* chore: ignore .serena directory

Author: houko

.gitignore

@@ -44,3 +44,4 @@ Thumbs.db
 *.swp
 *.swo
 *~
+.serena/

Cargo.lock

@@ -52,7 +52,7 @@ chrono = { version = "0.4", features = ["serde"] }
 chrono-tz = "0.10"
 
 # IDs
-uuid = { version = "1", features = ["v4", "serde"] }
+uuid = { version = "1", features = ["v4", "v5", "serde"] }
 
 # Database
 rusqlite = { version = "0.31", features = ["bundled", "serde_json"] }

Cargo.toml

@@ -1227,16 +1227,18 @@ impl OpenFangKernel {
 
     /// Spawn a new agent from a manifest, optionally linking to a parent agent.
     pub fn spawn_agent(&self, manifest: AgentManifest) -> KernelResult<AgentId> {
-        self.spawn_agent_with_parent(manifest, None)
+        self.spawn_agent_with_parent(manifest, None, None)
     }
 
     /// Spawn a new agent with an optional parent for lineage tracking.
+    /// If fixed_id is provided, use it instead of generating a new UUID.
     pub fn spawn_agent_with_parent(
         &self,
         manifest: AgentManifest,
         parent: Option<AgentId>,
+        fixed_id: Option<AgentId>,
     ) -> KernelResult<AgentId> {
-        let agent_id = AgentId::new();
+        let agent_id = fixed_id.unwrap_or_else(AgentId::new);
         let session_id = SessionId::new();
         let name = manifest.name.clone();
 
@@ -3279,8 +3281,10 @@ impl OpenFangKernel {
             let _ = self.kill_agent(old.id);
         }
 
-        // Spawn the agent
-        let agent_id = self.spawn_agent(manifest)?;
+        // Spawn the agent with a fixed ID based on hand_id for stable identity across restarts.
+        // This ensures triggers and cron jobs continue to work after daemon restart.
+        let fixed_agent_id = AgentId::from_string(hand_id);
+        let agent_id = self.spawn_agent_with_parent(manifest, None, Some(fixed_agent_id))?;
 
         // Restore triggers from the old agent under the new agent ID (#519).
         if !saved_triggers.is_empty() {
@@ -5500,7 +5504,7 @@ impl KernelHandle for OpenFangKernel {
         let name = manifest.name.clone();
         let parent = parent_id.and_then(|pid| pid.parse::<AgentId>().ok());
         let id = self
-            .spawn_agent_with_parent(manifest, parent)
+            .spawn_agent_with_parent(manifest, parent, None)
             .map_err(|e| format!("Spawn failed: {e}"))?;
         Ok((id.to_string(), name))
     }

crates/openfang-kernel/src/kernel.rs

@@ -117,6 +117,13 @@ impl AgentId {
     pub fn new() -> Self {
         Self(Uuid::new_v4())
     }
+
+    /// Create a deterministic AgentId from a string using SHA-1 namespace.
+    /// Useful for hand agents that need stable IDs across restarts.
+    pub fn from_string(s: &str) -> Self {
+        const NAMESPACE: Uuid = Uuid::NAMESPACE_DNS;
+        Self(Uuid::new_v5(&NAMESPACE, s.as_bytes()))
+    }
 }
 
 impl Default for AgentId {