fix(agents): propagate shared instruction edits

Refresh linked agent assignments from their definition at snapshot apply time and include the effective coordinates in restart drift detection.

Co-authored-by: Rizz <302abe414ca6e3134763d2539bfcf145aea2a63fe5f8455204ed602fd40cf381@buzz.block.builderlab.xyz>

Signed-off-by: Taylor Ho <taylorkmho@gmail.com>

desktop/src-tauri/src/managed_agents/persona_events.rs

@@ -433,6 +433,9 @@ pub struct PersonaSnapshot {
     pub system_prompt: Option<String>,
     pub model: Option<String>,
     pub provider: Option<String>,
+    /// Exact publisher-pinned shared-instruction coordinates, copied verbatim
+    /// from the definition so edits reach an existing instance on restart.
+    pub assigned_relay_skills: Vec<String>,
     /// Preferred ACP runtime ID, copied verbatim from the persona (including
     /// `None`). Unlike `model`/`provider`, there is no record-fallback: the
     /// materialized instance `runtime` must mirror the definition so that
@@ -454,14 +457,15 @@ pub fn persona_snapshot(persona: &AgentDefinition) -> PersonaSnapshot {
         system_prompt: Some(persona.system_prompt.clone()),
         model: persona.model.clone(),
         provider: persona.provider.clone(),
+        assigned_relay_skills: persona.assigned_relay_skills.clone(),
         runtime: persona.runtime.clone(),
         source_version: persona_content_hash(&persona_event_content(persona)),
     }
 }
 
 /// Re-pin `record` to `persona`: build a snapshot via [`persona_snapshot`]
-/// and mirror it onto the record — the definition quad
-/// (`system_prompt`/`model`/`provider`/`runtime`), the env-override
+/// and mirror it onto the record — the definition fields
+/// (`system_prompt`/`model`/`provider`/`runtime`/shared instructions), the env-override
 /// self-heal, and the `persona_source_version` drift basis.
 ///
 /// Definition-authoritative: blank definition model/provider produce `None`
@@ -484,6 +488,7 @@ pub fn apply_persona_snapshot(record: &mut ManagedAgentRecord, persona: &AgentDe
     }
     record.model = snapshot.model;
     record.provider = snapshot.provider;
+    record.assigned_relay_skills = snapshot.assigned_relay_skills;
     record.runtime = snapshot.runtime;
     // Drop a stale create-time harness pin when the definition switches to a
     // different known runtime (builtin, static preset, or loaded custom). A pin

desktop/src-tauri/src/managed_agents/persona_events/tests.rs

@@ -168,6 +168,18 @@ pub(super) fn sample_persona() -> AgentDefinition {
     }
 }
 
+#[test]
+fn apply_snapshot_refreshes_shared_instructions_for_existing_instance() {
+    let mut record = sample_record();
+    record.assigned_relay_skills = vec![format!("30023:{}:old", "a".repeat(64))];
+    let mut persona = sample_persona();
+    persona.assigned_relay_skills = vec![format!("30023:{}:new", "b".repeat(64))];
+
+    apply_persona_snapshot(&mut record, &persona);
+
+    assert_eq!(record.assigned_relay_skills, persona.assigned_relay_skills);
+}
+
 #[test]
 fn monotonic_created_at_bumps_past_head() {
     // No head: uses now (floor 0).

desktop/src-tauri/src/managed_agents/spawn_snapshot.rs

@@ -111,6 +111,8 @@ pub(crate) struct SpawnConfigSnapshot {
     pub system_prompt: Option<String>,
     pub model: Option<String>,
     pub provider: Option<String>,
+    /// Exact publisher-pinned shared-instruction coordinates exported to ACP.
+    pub assigned_relay_skills: Vec<String>,
     /// `None` when a user env override shadows `BUZZ_ACP_SESSION_TITLE`: spawn
     /// writes the title BEFORE the user env layer, so the override is what
     /// actually runs and it already reaches this snapshot through `env`.
@@ -193,6 +195,7 @@ impl SpawnConfigSnapshot {
             system_prompt: system_prompt.map(str::to_string),
             model: model.map(str::to_string),
             provider: provider.map(str::to_string),
+            assigned_relay_skills: record.assigned_relay_skills.clone(),
             session_title: (!descriptor.env.contains_key(SESSION_TITLE_ENV_VAR))
                 .then(|| resolve_session_title(record.display_name.as_deref(), &record.name))
                 .flatten(),

desktop/src-tauri/src/managed_agents/spawn_snapshot/diff/tests.rs

@@ -21,6 +21,7 @@ fn base() -> SpawnConfigSnapshot {
         system_prompt: Some("You are a test agent.".into()),
         model: Some("gpt-5".into()),
         provider: Some("openai".into()),
+        assigned_relay_skills: vec![format!("30023:{}:review", "a".repeat(64))],
         session_title: Some("Fizz".into()),
         auth_tag: Some("tag-abcdefgh".into()),
         respond_to: "owner-only".into(),
@@ -62,6 +63,7 @@ fn mutations() -> Vec<Mutation> {
         ("system_prompt", |s| s.system_prompt = None),
         ("model", |s| s.model = None),
         ("provider", |s| s.provider = None),
+        ("assigned_relay_skills", |s| s.assigned_relay_skills.clear()),
         ("session_title", |s| s.session_title = None),
         ("auth_tag", |s| s.auth_tag = None),
         ("respond_to", |s| s.respond_to = "anyone".into()),

desktop/src-tauri/src/managed_agents/spawn_snapshot/tests.rs

@@ -223,6 +223,27 @@ fn persona_prompt_edit_changes_snapshot() {
     );
 }
 
+#[test]
+fn persona_shared_instruction_edit_changes_snapshot() {
+    let mut rec = record();
+    rec.persona_id = Some("pers".into());
+    let mut before = persona("pers", Some("goose"), "prompt");
+    before.assigned_relay_skills = vec![format!("30023:{}:before", "a".repeat(64))];
+    let mut after = before.clone();
+    after.assigned_relay_skills = vec![format!("30023:{}:after", "b".repeat(64))];
+
+    assert_ne!(
+        snapshot(
+            &rec,
+            &[before],
+            &[],
+            "wss://ws.example",
+            &Default::default()
+        ),
+        snapshot(&rec, &[after], &[], "wss://ws.example", &Default::default())
+    );
+}
+
 #[test]
 fn workspace_relay_change_trips_snapshot_even_for_stored_record_relay() {
     // The legacy per-record relay pin is ignored (#2122): every record spawns