fix(orchestrator,plugins): contact cross-project corrélé + découvrabilité assignation plugin par agent — #284 (backend: registre des demandes actives clé projet/agent appelant + correlationId, refus corrélation vide/dupliquée, cancel routé après correspondance exacte sans redirection vers une autre cible, appelant projeté Waiting→Done dans le live-state de son propre projet avec correlationId exposé par idea_workstate_read, gardes RAII réconcilient l'abandon du futur, tools ask/cancel WriteAction deny-by-default dont le refus indique où activer la permission; frontend: action Attribuer aux agents depuis Settings projet > Plugins ouvrant le panneau Agents flottant/ancré/détaché, section Capabilities de plugins — {agent} explicitant attribution skills et tools MCP des plugins activés; QA verte: orchestrator_service 79/79, mcp_server 40/40, domain live_state 15/15, correlated_update_is_preserved_in_the_lean_projection 1/1, frontend ProjectPluginSettings 3 tests, npm run build frontend, cargo fmt --check, git diff --check; AppImage IdeA_0.3.0_amd64.AppImage rebuildée workflow build-appimage, validation live cross-project restant après remplacement/relance manuels; réserves: registre corrélation en mémoire non persisté, surface web unsupported, catalogue dynamique tools MCP = réserve #282)

crates/application/src/orchestrator/service.rs

@@ -401,6 +401,68 @@ impl Drop for LiveStateTurnGuard {
     }
 }
 
+/// Drop-safe caller-side live-state cleanup for a cross-project request.
+struct CrossProjectLiveStateGuard {
+    update: Option<Arc<UpdateLiveState>>,
+    requester: AgentId,
+    correlation_id: String,
+    armed: bool,
+}
+
+impl CrossProjectLiveStateGuard {
+    fn new(
+        update: Option<Arc<UpdateLiveState>>,
+        requester: AgentId,
+        correlation_id: String,
+    ) -> Self {
+        Self {
+            update,
+            requester,
+            correlation_id,
+            armed: true,
+        }
+    }
+
+    fn disarm(&mut self) {
+        self.armed = false;
+    }
+}
+
+impl Drop for CrossProjectLiveStateGuard {
+    fn drop(&mut self) {
+        if !self.armed {
+            return;
+        }
+        let Some(update) = self.update.clone() else {
+            return;
+        };
+        let requester = self.requester;
+        let correlation_id = self.correlation_id.clone();
+        if let Ok(handle) = tokio::runtime::Handle::try_current() {
+            handle.spawn(async move {
+                if let Err(error) = update
+                    .execute_correlated(
+                        UpdateLiveStateInput {
+                            agent_id: requester,
+                            ticket: None,
+                            intent: String::new(),
+                            status: domain::live_state::WorkStatus::Done,
+                            progress: None,
+                            last_delegation: None,
+                        },
+                        correlation_id.clone(),
+                    )
+                    .await
+                {
+                    crate::diag!(
+                        "[cross-project] caller drop cleanup failed: requester={requester} correlation={correlation_id} err={error}"
+                    );
+                }
+            });
+        }
+    }
+}
+
 /// Fournit les faits OS/runtime (exe + endpoint projet) pour écrire la déclaration MCP
 /// réelle quand l'orchestrateur (re)lance une cible sur le chemin `ask`. Implémenté dans
 /// app-tauri (seul détenteur de current_exe/$APPIMAGE/mcp_endpoint).
@@ -513,6 +575,9 @@ pub struct OrchestratorService {
     /// attach `idea_run_in_background` tasks for observability/cancellation while the
     /// synchronous answer remains the first structured `Final`.
     active_rendezvous: StdMutex<HashMap<RuntimeAgentKey, ActiveRendezvous>>,
+    /// Active cross-project calls keyed by caller identity and caller-supplied
+    /// correlation id. Cancel uses this registry as its routing authority.
+    cross_project_requests: StdMutex<HashMap<CrossProjectRequestKey, ActiveCrossProjectRequest>>,
     /// Bus d'événements pour publier [`DomainEvent::AgentReplied`] à l'issue d'un
     /// `ask` réussi (§17.4). Injecté via [`Self::with_events`] ; `None` ⇒ pas de
     /// publication (l'`ask` fonctionne quand même).
@@ -653,6 +718,19 @@ struct ActiveRendezvous {
     background_tasks: Vec<TaskId>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+struct CrossProjectRequestKey {
+    requester_project_id: domain::ProjectId,
+    requester_agent_id: AgentId,
+    correlation_id: String,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct ActiveCrossProjectRequest {
+    target_project_id: domain::ProjectId,
+    target_agent_id: AgentId,
+}
+
 impl OrchestratorService {
     /// Builds the service from the use cases and ports it dispatches to.
     #[must_use]
@@ -683,6 +761,7 @@ impl OrchestratorService {
             wait_for: StdMutex::new(WaitForGraph::new()),
             active_waits: StdMutex::new(Vec::new()),
             active_rendezvous: StdMutex::new(HashMap::new()),
+            cross_project_requests: StdMutex::new(HashMap::new()),
             events: None,
             ask_locks: StdMutex::new(HashMap::new()),
             mcp_runtime_provider: None,
@@ -1216,6 +1295,91 @@ impl OrchestratorService {
         }
     }
 
+    async fn mark_cross_project_requester_best_effort(
+        &self,
+        root: &ProjectPath,
+        requester: AgentId,
+        status: domain::live_state::WorkStatus,
+        intent: String,
+        correlation_id: String,
+    ) {
+        let Some(provider) = &self.live_state else {
+            return;
+        };
+        let Some(update) = provider.live_state_for(root) else {
+            return;
+        };
+        if let Err(error) = update
+            .execute_correlated(
+                UpdateLiveStateInput {
+                    agent_id: requester,
+                    ticket: None,
+                    intent,
+                    status,
+                    progress: None,
+                    last_delegation: None,
+                },
+                correlation_id.clone(),
+            )
+            .await
+        {
+            crate::diag!(
+                "[cross-project] caller live-state update failed: requester={requester} correlation={correlation_id} err={error}"
+            );
+        }
+    }
+
+    fn register_cross_project_request(
+        &self,
+        requester_project_id: domain::ProjectId,
+        requester_agent_id: AgentId,
+        correlation_id: String,
+        target_project_id: domain::ProjectId,
+        target_agent_id: AgentId,
+    ) -> Result<CrossProjectRequestGuard<'_>, AppError> {
+        if correlation_id.trim().is_empty() {
+            return Err(AppError::Invalid(
+                "cross-project correlationId must not be empty".to_owned(),
+            ));
+        }
+        if correlation_id.len() > domain::live_state::FIELD_MAX_BYTES {
+            return Err(AppError::Invalid(format!(
+                "cross-project correlationId exceeds {} bytes",
+                domain::live_state::FIELD_MAX_BYTES
+            )));
+        }
+        let key = CrossProjectRequestKey {
+            requester_project_id,
+            requester_agent_id,
+            correlation_id,
+        };
+        let target = ActiveCrossProjectRequest {
+            target_project_id,
+            target_agent_id,
+        };
+        let mut active = self
+            .cross_project_requests
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        if let Some(existing) = active.get(&key) {
+            return Err(AppError::Invalid(format!(
+                "cross-project correlationId `{}` is already active for requester {}/{} (target {}/{})",
+                key.correlation_id,
+                key.requester_project_id,
+                key.requester_agent_id,
+                existing.target_project_id,
+                existing.target_agent_id
+            )));
+        }
+        active.insert(key.clone(), target);
+        drop(active);
+        Ok(CrossProjectRequestGuard {
+            active: &self.cross_project_requests,
+            key,
+            target,
+        })
+    }
+
     /// Persiste **best-effort** un tour (`Prompt`/`Response`) dans `conversation`.
     ///
     /// No-op silencieux quand le provider/horloge ne sont pas câblés, quand le provider
@@ -1460,6 +1624,18 @@ impl OrchestratorService {
         requester_agent_id: AgentId,
         correlation_id: String,
     ) -> Result<OrchestratorOutcome, AppError> {
+        let requester_project = self
+            .load_project_for_cross_tool(requester_project_id)
+            .await?;
+        if self
+            .find_agent_by_id(&requester_project, requester_agent_id)
+            .await?
+            .is_none()
+        {
+            return Err(AppError::NotFound(format!(
+                "requester agent {requester_agent_id} in project {requester_project_id}"
+            )));
+        }
         let project = self.load_project_for_cross_tool(target_project_id).await?;
         let target = self
             .find_agent_by_id(&project, target_agent_id)
@@ -1470,11 +1646,46 @@ impl OrchestratorService {
                 "agent {target_agent_id} is not contactable cross-project"
             )));
         }
+        let _request_guard = self.register_cross_project_request(
+            requester_project_id,
+            requester_agent_id,
+            correlation_id.clone(),
+            target_project_id,
+            target_agent_id,
+        )?;
         crate::diag!(
             "[cross-project] ask correlation={correlation_id} requester={requester_project_id}/{requester_agent_id} target={target_project_id}/{target_agent_id}"
         );
-        self.ask_resolved_agent(&project, target, task, Some(requester_agent_id))
+        self.mark_cross_project_requester_best_effort(
-            .await
+            &requester_project.root,
+            requester_agent_id,
+            domain::live_state::WorkStatus::Waiting,
+            Self::distill_intent(&format!("Waiting for {} in another project", target.name)),
+            correlation_id.clone(),
+        )
+        .await;
+        let caller_update = self
+            .live_state
+            .as_ref()
+            .and_then(|provider| provider.live_state_for(&requester_project.root));
+        let mut caller_live_guard = CrossProjectLiveStateGuard::new(
+            caller_update,
+            requester_agent_id,
+            correlation_id.clone(),
+        );
+        let result = self
+            .ask_resolved_agent(&project, target, task, Some(requester_agent_id))
+            .await;
+        self.mark_cross_project_requester_best_effort(
+            &requester_project.root,
+            requester_agent_id,
+            domain::live_state::WorkStatus::Done,
+            String::new(),
+            correlation_id,
+        )
+        .await;
+        caller_live_guard.disarm();
+        result
     }
 
     /// Cancels/stops one contactable agent in another project by stable ids.
@@ -1486,22 +1697,47 @@ impl OrchestratorService {
         requester_agent_id: AgentId,
         correlation_id: String,
     ) -> Result<OrchestratorOutcome, AppError> {
-        let project = self.load_project_for_cross_tool(target_project_id).await?;
+        let key = CrossProjectRequestKey {
-        let target = self
+            requester_project_id,
-            .find_agent_by_id(&project, target_agent_id)
+            requester_agent_id,
-            .await?
+            correlation_id: correlation_id.clone(),
-            .ok_or_else(|| AppError::NotFound(format!("agent {target_agent_id}")))?;
+        };
-        if !target.contactable {
+        let active = self
+            .cross_project_requests
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .get(&key)
+            .copied()
+            .ok_or_else(|| {
+                AppError::NotFound(format!(
+                    "active cross-project request with correlationId `{correlation_id}` for requester {requester_project_id}/{requester_agent_id}"
+                ))
+            })?;
+        if active.target_project_id != target_project_id
+            || active.target_agent_id != target_agent_id
+        {
             return Err(AppError::Invalid(format!(
-                "agent {target_agent_id} is not contactable cross-project"
+                "cross-project correlationId `{correlation_id}` belongs to target {}/{}, not {target_project_id}/{target_agent_id}",
+                active.target_project_id, active.target_agent_id
             )));
         }
+        let project = self
+            .load_project_for_cross_tool(active.target_project_id)
+            .await?;
+        let target = self
+            .find_agent_by_id(&project, active.target_agent_id)
+            .await?
+            .ok_or_else(|| AppError::NotFound(format!("agent {}", active.target_agent_id)))?;
         crate::diag!(
             "[cross-project] cancel correlation={correlation_id} requester={requester_project_id}/{requester_agent_id} target={target_project_id}/{target_agent_id}"
         );
-        let _ = requester_agent_id;
+        let mut outcome = self
-        self.stop_agent_by_id(&project, target.id, target.name, None)
+            .stop_agent_by_id(&project, target.id, target.name, None)
-            .await
+            .await?;
+        outcome.detail = format!(
+            "cancelled cross-project request correlationId `{correlation_id}` for target {target_project_id}/{target_agent_id}"
+        );
+        Ok(outcome)
     }
 
     async fn run_in_background(
@@ -1714,7 +1950,7 @@ impl OrchestratorService {
     /// name, returned inline as a JSON array. Entries whose agent is no longer in the
     /// manifest are dropped; `progress` is **never** exposed (the lean DTO has none).
     ///
-    /// Shape: `[{"agent","status","intent","ticket?","lastDelegation?"}]`.
+    /// Shape: `[{"agent","status","intent","ticket?","lastDelegation?","correlationId?"}]`.
     async fn read_workstate(
         &self,
         project: &Project,
@@ -1756,6 +1992,9 @@ impl OrchestratorService {
                 if let Some(last) = entry.last_delegation {
                     row["lastDelegation"] = serde_json::json!(last);
                 }
+                if let Some(correlation_id) = entry.correlation_id {
+                    row["correlationId"] = serde_json::json!(correlation_id);
+                }
                 Some(row)
             })
             .collect();
@@ -3440,6 +3679,24 @@ impl Drop for ActiveRendezvousGuard<'_> {
     }
 }
 
+struct CrossProjectRequestGuard<'a> {
+    active: &'a StdMutex<HashMap<CrossProjectRequestKey, ActiveCrossProjectRequest>>,
+    key: CrossProjectRequestKey,
+    target: ActiveCrossProjectRequest,
+}
+
+impl Drop for CrossProjectRequestGuard<'_> {
+    fn drop(&mut self) {
+        let mut active = self
+            .active
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        if active.get(&self.key) == Some(&self.target) {
+            active.remove(&self.key);
+        }
+    }
+}
+
 /// Normalises a profile reference for tolerant matching: lowercased, with spaces,
 /// dashes and underscores stripped (`"Claude Code"`, `"claude-code"`, `"claude"`
 /// → comparable forms; `claude` ⊂ ... handled by the command match above).

crates/application/src/workstate/live.rs

@@ -85,6 +85,24 @@ impl UpdateLiveState {
     /// [`AppError::Invalid`] if a text field exceeds the domain hard threshold;
     /// [`AppError::Store`] on a persistence failure.
     pub async fn execute(&self, input: UpdateLiveStateInput) -> Result<(), AppError> {
+        self.execute_with_correlation(input, None).await
+    }
+
+    /// Publishes a transition carrying an external cross-project correlation id.
+    pub async fn execute_correlated(
+        &self,
+        input: UpdateLiveStateInput,
+        correlation_id: String,
+    ) -> Result<(), AppError> {
+        self.execute_with_correlation(input, Some(correlation_id))
+            .await
+    }
+
+    async fn execute_with_correlation(
+        &self,
+        input: UpdateLiveStateInput,
+        correlation_id: Option<String>,
+    ) -> Result<(), AppError> {
         let now_ms = u64::try_from(self.clock.now_millis()).unwrap_or(0);
         let entry = LiveEntry::new(
             input.agent_id,
@@ -95,6 +113,7 @@ impl UpdateLiveState {
             input.last_delegation,
             now_ms,
         )
+        .and_then(|entry| entry.with_correlation_id(correlation_id))
         .map_err(|e| AppError::Invalid(e.to_string()))?;
         self.store.upsert(entry).await?;
         Ok(())
@@ -117,6 +136,9 @@ pub struct LeanLiveEntry {
     pub ticket: Option<TicketId>,
     /// The ticket of the most recent delegation it issued, if any.
     pub last_delegation: Option<TicketId>,
+    /// External correlation for an active/completed cross-project request.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub correlation_id: Option<String>,
 }
 
 impl From<LiveEntry> for LeanLiveEntry {
@@ -127,6 +149,7 @@ impl From<LiveEntry> for LeanLiveEntry {
             status: e.status,
             ticket: e.ticket,
             last_delegation: e.last_delegation,
+            correlation_id: e.correlation_id,
         }
     }
 }
@@ -246,6 +269,32 @@ mod tests {
         );
     }
 
+    #[tokio::test]
+    async fn correlated_update_is_preserved_in_the_lean_projection() {
+        let store = Arc::new(InMemoryLiveStateStore::default());
+        let uc = UpdateLiveState::new(store.clone(), Arc::new(FixedClock(4_242)));
+
+        uc.execute_correlated(
+            UpdateLiveStateInput {
+                agent_id: aid(1),
+                ticket: None,
+                intent: "waiting for another project".to_owned(),
+                status: WorkStatus::Waiting,
+                progress: None,
+                last_delegation: None,
+            },
+            "cross-284".to_owned(),
+        )
+        .await
+        .unwrap();
+
+        let lean = GetLiveStateLean::new(store, Arc::new(FixedClock(4_242)))
+            .execute()
+            .await
+            .unwrap();
+        assert_eq!(lean.entries[0].correlation_id.as_deref(), Some("cross-284"));
+    }
+
     #[tokio::test]
     async fn update_applies_domain_bounds_truncation() {
         let store = Arc::new(InMemoryLiveStateStore::default());

crates/application/tests/orchestrator_service.rs

@@ -902,7 +902,10 @@ async fn cross_project_list_agents_filters_to_contactable_agents() {
     let target_project = other_project();
     let svc = fx
         .service
-        .with_project_store(Arc::new(FakeProjects::new(vec![target_project.clone()])));
+        .with_project_store(Arc::new(FakeProjects::new(vec![
+            project(),
+            target_project.clone(),
+        ])));
 
     let out = svc
         .list_project_agents_for_mcp(target_project.id)
@@ -919,11 +922,17 @@ async fn cross_project_list_agents_filters_to_contactable_agents() {
 #[tokio::test]
 async fn cross_project_ask_rejects_non_contactable_agent_before_launch() {
     let hidden = scratch_agent(aid(2), "Hidden", "agents/hidden.md");
-    let fx = fixture(FakeContexts::with_agent(&hidden, "# hidden"));
+    let requester = scratch_agent(aid(99), "Requester", "agents/requester.md");
+    let contexts = FakeContexts::with_agent(&hidden, "# hidden");
+    contexts.add_agent(&requester, "# requester");
+    let fx = fixture(contexts);
     let target_project = other_project();
     let svc = fx
         .service
-        .with_project_store(Arc::new(FakeProjects::new(vec![target_project.clone()])));
+        .with_project_store(Arc::new(FakeProjects::new(vec![
+            project(),
+            target_project.clone(),
+        ])));
 
     let err = svc
         .ask_project_agent_for_mcp(
@@ -950,6 +959,10 @@ async fn cross_project_ask_routes_by_agent_id_when_names_collide() {
         scratch_agent(aid(2), "Architect", "agents/architect-second.md").with_contactable(true);
     let contexts = FakeContexts::with_agent(&first, "# first");
     contexts.add_agent(&second, "# second");
+    contexts.add_agent(
+        &scratch_agent(aid(99), "Requester", "agents/requester.md"),
+        "# requester",
+    );
     let fx = ask_fixture(contexts);
     let target_project = other_project();
 
@@ -989,6 +1002,10 @@ async fn cross_project_cancel_routes_by_agent_id_when_names_collide() {
         scratch_agent(aid(2), "Architect", "agents/architect-second.md").with_contactable(true);
     let contexts = FakeContexts::with_agent(&first, "# first");
     contexts.add_agent(&second, "# second");
+    contexts.add_agent(
+        &scratch_agent(aid(99), "Requester", "agents/requester.md"),
+        "# requester",
+    );
     let fx = ask_fixture(contexts);
     let target_project = other_project();
     let first_cancelled = Arc::new(Mutex::new(0_u32));
@@ -1012,7 +1029,27 @@ async fn cross_project_cancel_routes_by_agent_id_when_names_collide() {
     fx.structured
         .insert_in_project(target_project.id, second_session, second.id, nid(9102));
 
-    timeout(
+    let ask_service = Arc::clone(&fx.service);
+    let ask = tokio::spawn(async move {
+        ask_service
+            .ask_project_agent_for_mcp(
+                target_project.id,
+                second.id,
+                "work".to_owned(),
+                project().id,
+                aid(99),
+                "corr-homonym-cancel".to_owned(),
+            )
+            .await
+    });
+    await_until(|| {
+        fx.live
+            .entry_for(aid(99))
+            .is_some_and(|entry| entry.status == WorkStatus::Waiting)
+    })
+    .await;
+
+    let cancelled = timeout(
         TEST_GUARD,
         fx.service.cancel_project_agent_for_mcp(
             target_project.id,
@@ -1026,8 +1063,95 @@ async fn cross_project_cancel_routes_by_agent_id_when_names_collide() {
     .expect("cross-project cancel must not hang")
     .expect("cross-project cancel ok");
 
+    assert!(cancelled.detail.contains("corr-homonym-cancel"));
     assert_eq!(*first_cancelled.lock().unwrap(), 0);
     assert_eq!(*second_cancelled.lock().unwrap(), 1);
+
+    fx.mailbox
+        .completions()
+        .push(second.id, TestCompletion::Cancelled);
+    let _ = timeout(TEST_GUARD, ask)
+        .await
+        .expect("cancelled ask must settle")
+        .expect("ask join");
+}
+
+#[tokio::test]
+async fn cross_project_ask_projects_correlation_on_requester_and_rejects_wrong_cancel() {
+    let target = scratch_agent(aid(2), "Target", "agents/target.md").with_contactable(true);
+    let requester = scratch_agent(aid(99), "Requester", "agents/requester.md");
+    let contexts = FakeContexts::with_agent(&target, "# target");
+    contexts.add_agent(&requester, "# requester");
+    let fx = ask_fixture(contexts);
+    let target_project = other_project();
+
+    let ask_service = Arc::clone(&fx.service);
+    let ask = tokio::spawn(async move {
+        ask_service
+            .ask_project_agent_for_mcp(
+                target_project.id,
+                target.id,
+                "work".to_owned(),
+                project().id,
+                requester.id,
+                "corr-visible".to_owned(),
+            )
+            .await
+    });
+
+    await_until(|| {
+        fx.live.entry_for(requester.id).is_some_and(|entry| {
+            entry.status == WorkStatus::Waiting
+                && entry.correlation_id.as_deref() == Some("corr-visible")
+        })
+    })
+    .await;
+    let workstate = fx
+        .service
+        .dispatch(
+            &project(),
+            OrchestratorCommand::ReadWorkState {
+                requester: ConversationParty::agent(requester.id),
+            },
+        )
+        .await
+        .expect("caller workstate readable");
+    let rows: serde_json::Value =
+        serde_json::from_str(workstate.reply.as_deref().unwrap()).unwrap();
+    let requester_row = rows
+        .as_array()
+        .unwrap()
+        .iter()
+        .find(|row| row["agent"] == "Requester")
+        .expect("requester projection");
+    assert_eq!(requester_row["status"], "waiting");
+    assert_eq!(requester_row["correlationId"], "corr-visible");
+
+    let mismatch = fx
+        .service
+        .cancel_project_agent_for_mcp(
+            target_project.id,
+            aid(1),
+            project().id,
+            requester.id,
+            "corr-visible".to_owned(),
+        )
+        .await
+        .expect_err("correlation must not be redirectable to another target");
+    assert!(mismatch.to_string().contains("belongs to target"));
+
+    fx.mailbox
+        .completions()
+        .push(target.id, TestCompletion::Replied("done".to_owned()));
+    let out = timeout(TEST_GUARD, ask)
+        .await
+        .expect("ask settles")
+        .expect("ask join")
+        .expect("ask succeeds");
+    assert_eq!(out.reply.as_deref(), Some("done"));
+    let caller = fx.live.entry_for(requester.id).expect("caller row remains");
+    assert_eq!(caller.status, WorkStatus::Done);
+    assert_eq!(caller.correlation_id.as_deref(), Some("corr-visible"));
 }
 
 #[tokio::test]

crates/domain/src/live_state.rs

@@ -106,6 +106,9 @@ pub struct LiveEntry {
     pub progress: Option<String>,
     /// The ticket of the most recent delegation this agent issued, if any.
     pub last_delegation: Option<TicketId>,
+    /// External correlation carried by an active cross-project request, if any.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub correlation_id: Option<String>,
     /// Wall-clock update time in epoch milliseconds (drives `prune` ordering).
     pub updated_at_ms: u64,
 }
@@ -138,9 +141,35 @@ impl LiveEntry {
             status,
             progress,
             last_delegation,
+            correlation_id: None,
             updated_at_ms,
         })
     }
+
+    /// Attaches a validated external correlation id to this projection.
+    ///
+    /// Unlike human-readable preview fields, correlation ids are never truncated:
+    /// changing the value would make cancellation routing ambiguous.
+    pub fn with_correlation_id(
+        mut self,
+        correlation_id: Option<String>,
+    ) -> Result<Self, DomainError> {
+        if let Some(value) = correlation_id {
+            if value.trim().is_empty() {
+                return Err(DomainError::Invariant(
+                    "live-state correlation id must not be empty".to_owned(),
+                ));
+            }
+            if value.len() > FIELD_MAX_BYTES {
+                return Err(DomainError::Invariant(format!(
+                    "live-state correlation id exceeds the max size of {FIELD_MAX_BYTES} bytes ({} bytes)",
+                    value.len()
+                )));
+            }
+            self.correlation_id = Some(value);
+        }
+        Ok(self)
+    }
 }
 
 /// Enforces the field bounds: reject above the hard byte threshold, otherwise
@@ -224,6 +253,7 @@ impl LiveState {
                 status: WorkStatus::Idle,
                 progress: Some(STALE_AT_RESTART_MARKER.to_owned()),
                 last_delegation: None,
+                correlation_id: e.correlation_id.clone(),
                 updated_at_ms: now_ms,
             })
             .collect()

crates/infrastructure/src/orchestrator/mcp/server.rs

@@ -443,9 +443,14 @@ impl McpServer {
         } else {
             &self.requester
         };
+        let guidance = if matches!(name, "idea_project_ask_agent" | "idea_project_cancel_agent") {
+            "; enable this cross-project action in the requester's project MCP tool permissions"
+        } else {
+            ""
+        };
         Err(JsonRpcError::new(
             error_codes::INVALID_PARAMS,
-            format!("MCP tool `{name}` is not permitted for requester {requester}"),
+            format!("MCP tool `{name}` is not permitted for requester {requester}{guidance}"),
         ))
     }
 

crates/infrastructure/src/orchestrator/mcp/tools.rs

@@ -228,7 +228,7 @@ pub fn catalogue() -> Vec<ToolDef> {
         },
         ToolDef {
             name: "idea_project_ask_agent",
-            description: "Ask a cross-project contactable agent by projectId and agentId and wait for its final answer.",
+            description: "Ask a cross-project contactable agent by projectId and agentId and wait for its final answer. Requires explicit permission in the requester's project MCP tool settings.",
             input_schema: json!({
                 "type": "object",
                 "properties": {
@@ -243,7 +243,7 @@ pub fn catalogue() -> Vec<ToolDef> {
         },
         ToolDef {
             name: "idea_project_cancel_agent",
-            description: "Cancel/stop a cross-project contactable agent by projectId, agentId and correlationId.",
+            description: "Cancel an active cross-project request by the same projectId, agentId and correlationId used for the ask. Requires explicit permission in the requester's project MCP tool settings.",
             input_schema: json!({
                 "type": "object",
                 "properties": {

crates/infrastructure/tests/mcp_server.rs

@@ -928,6 +928,60 @@ async fn requester_with_durable_store_but_no_override_sees_read_only_tools() {
     assert!(!names.contains(&"idea_template_delete"));
     assert!(!names.contains(&"idea_plugin_install_from_directory"));
     assert!(!names.contains(&"idea_plugin_reload"));
+    assert!(!names.contains(&"idea_project_ask_agent"));
+    assert!(!names.contains(&"idea_project_cancel_agent"));
+}
+
+#[tokio::test]
+async fn cross_project_actions_are_advertised_only_when_allowed_and_denial_is_actionable() {
+    let (service, _s) = build_service(FakeContexts::new());
+    let agent = AgentId::from_uuid(Uuid::from_u128(284));
+    let allowed = server_with_mcp_permissions(
+        Arc::clone(&service),
+        allow_doc(
+            agent,
+            &["idea_project_ask_agent", "idea_project_cancel_agent"],
+        ),
+    )
+    .for_requester(agent.to_string());
+
+    let listed = allowed
+        .handle_raw(
+            &serde_json::to_vec(&json!({
+                "jsonrpc": "2.0", "id": 284, "method": "tools/list"
+            }))
+            .unwrap(),
+        )
+        .await
+        .expect("tools/list reply");
+    let listed_result = listed.result.unwrap();
+    let names: Vec<&str> = listed_result["tools"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|tool| tool["name"].as_str().unwrap())
+        .collect();
+    assert!(names.contains(&"idea_project_ask_agent"));
+    assert!(names.contains(&"idea_project_cancel_agent"));
+
+    let denied = server_with_mcp_permissions(service, ProjectMcpToolPermissions::default())
+        .for_requester(agent.to_string());
+    let response = denied
+        .handle_raw(&tools_call(
+            285,
+            "idea_project_ask_agent",
+            json!({
+                "projectId": Uuid::from_u128(2),
+                "agentId": Uuid::from_u128(3),
+                "correlationId": "corr-denied",
+                "task": "work"
+            }),
+        ))
+        .await
+        .expect("denied call reply");
+    let error = response.error.expect("permission error");
+    assert!(error.message.contains("not permitted"));
+    assert!(error.message.contains("project MCP tool permissions"));
 }
 
 // ---------------------------------------------------------------------------

frontend/src/features/plugins/AgentPluginCapabilities.tsx

@@ -68,10 +68,20 @@ export function AgentPluginCapabilities({
 
   return (
     <div className="flex flex-col gap-4">
+      <div>
+        <h4 className="text-sm font-semibold text-content">
+          Capabilities de plugins — {agentName}
+        </h4>
+        <p className="mt-1 text-xs text-muted">
+          Attribuez à cet agent les skills et tools MCP fournis par les plugins activés
+          dans les paramètres du projet.
+        </p>
+      </div>
+
       {vm.error && <p role="alert" className="text-xs text-danger">{vm.error}</p>}
 
       <section aria-label={`Skills de plugins — ${agentName}`} className="flex flex-col gap-2">
-        <h4 className="text-sm font-semibold text-content">Skills de plugins</h4>
+        <h5 className="text-sm font-semibold text-content">Skills de plugins</h5>
         {enabledPlugins.every((plugin) => (plugin.contributes.skills ?? []).length === 0) ? (
           <p className="text-xs text-muted">Aucun skill fourni par les plugins activés pour ce projet.</p>
         ) : (
@@ -80,7 +90,7 @@ export function AgentPluginCapabilities({
             if (skills.length === 0) return null;
             return (
               <Panel key={plugin.id} className="flex flex-col gap-2">
-                <h5 className="text-xs font-semibold text-content">{plugin.displayName}</h5>
+                <h6 className="text-xs font-semibold text-content">{plugin.displayName}</h6>
                 {skills.map((skill) => {
                   const assigned = assignedSkills.has(`${plugin.id}:${skill.id}`);
                   return (
@@ -110,7 +120,7 @@ export function AgentPluginCapabilities({
       </section>
 
       <section aria-label={`Tools MCP de plugins — ${agentName}`} className="flex flex-col gap-2">
-        <h4 className="text-sm font-semibold text-content">Tools MCP de plugins</h4>
+        <h5 className="text-sm font-semibold text-content">Tools MCP de plugins</h5>
         {assignedTools.length === 0 ? (
           <p className="text-xs text-muted">Aucun tool MCP de plugin attribué à l’agent.</p>
         ) : (

frontend/src/features/plugins/PluginsPanel.tsx

@@ -38,9 +38,10 @@ interface InstallFlow {
 
 export interface PluginsPanelProps {
   projectId?: string;
+  onAssignAgents?: () => void;
 }
 
-export function PluginsPanel({ projectId }: PluginsPanelProps = {}) {
+export function PluginsPanel({ projectId, onAssignAgents }: PluginsPanelProps = {}) {
   const vm = usePlugins();
   const pluginRuntime = usePluginRuntime();
   const [pendingAction, setPendingAction] = useState<PendingAction | null>(null);
@@ -93,7 +94,7 @@ export function PluginsPanel({ projectId }: PluginsPanelProps = {}) {
   return (
     <div className="flex flex-col gap-4">
       {projectId ? (
-        <ProjectPluginsPanel projectId={projectId} />
+        <ProjectPluginsPanel projectId={projectId} onAssignAgents={onAssignAgents} />
       ) : (
         <Panel>
           <p className="text-sm text-muted">

frontend/src/features/plugins/ProjectPluginSettings.test.tsx

@@ -1,5 +1,5 @@
 import { fireEvent, render, screen, waitFor } from "@testing-library/react";
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 
 import { DIProvider } from "@/app/di";
 import { createMockGateways, MockPluginGateway } from "@/adapters/mock";
@@ -63,6 +63,22 @@ describe("project plugin settings #282", () => {
     ]);
   });
 
+  it("offers an obvious entry point to assign plugin capabilities to agents", async () => {
+    const gateways = gatewaysWithPlugin();
+    const onAssignAgents = vi.fn();
+    render(
+      <DIProvider gateways={gateways}>
+        <ProjectPluginsPanel
+          projectId="project-1"
+          onAssignAgents={onAssignAgents}
+        />
+      </DIProvider>,
+    );
+
+    fireEvent.click(await screen.findByRole("button", { name: "Attribuer aux agents" }));
+    expect(onAssignAgents).toHaveBeenCalledOnce();
+  });
+
   it("assigns plugin skills and MCP tools to an agent and keeps stale references removable", async () => {
     const gateways = gatewaysWithPlugin();
     gateways.plugin._seedProjectPluginSettings("project-1", {
@@ -80,6 +96,7 @@ describe("project plugin settings #282", () => {
       </DIProvider>,
     );
 
+    expect(await screen.findByText("Capabilities de plugins — Dev")).toBeTruthy();
     const skill = await screen.findByRole("checkbox", { name: /unity-debug/ });
     fireEvent.click(skill);
     await waitFor(() => expect((skill as HTMLInputElement).checked).toBe(true));

frontend/src/features/plugins/ProjectPluginsPanel.tsx

@@ -1,15 +1,19 @@
-import { Panel, Spinner } from "@/shared";
+import { Button, Panel, Spinner } from "@/shared";
 import { useProjectPlugins } from "./useProjectPlugins";
 
 export interface ProjectPluginsPanelProps {
   projectId: string;
+  onAssignAgents?: () => void;
 }
 
 function countLabel(count: number, singular: string, plural: string): string {
   return `${count} ${count === 1 ? singular : plural}`;
 }
 
-export function ProjectPluginsPanel({ projectId }: ProjectPluginsPanelProps) {
+export function ProjectPluginsPanel({
+  projectId,
+  onAssignAgents,
+}: ProjectPluginsPanelProps) {
   const vm = useProjectPlugins(projectId);
 
   if (vm.loading && !vm.settings) {
@@ -28,12 +32,19 @@ export function ProjectPluginsPanel({ projectId }: ProjectPluginsPanelProps) {
 
   return (
     <section aria-label="plugins du projet" className="flex flex-col gap-3">
-      <div>
+      <div className="flex items-start justify-between gap-4">
-        <h2 className="text-sm font-semibold text-content">Plugins du projet</h2>
+        <div>
-        <p className="mt-1 text-xs text-muted">
+          <h2 className="text-sm font-semibold text-content">Plugins du projet</h2>
-          Un plugin reste installé globalement. Activez-le ici avant d’attribuer ses
+          <p className="mt-1 text-xs text-muted">
-          capabilities aux agents de ce projet.
+            Activez les plugins utilisés par ce projet, puis attribuez leurs skills et
-        </p>
+            tools MCP à chaque agent.
+          </p>
+        </div>
+        {onAssignAgents && (
+          <Button size="sm" variant="primary" onClick={onAssignAgents}>
+            Attribuer aux agents
+          </Button>
+        )}
       </div>
 
       {vm.error && <p role="alert" className="text-sm text-danger">{vm.error}</p>}

frontend/src/features/projects/ProjectsView.tsx

@@ -910,6 +910,12 @@ export function ProjectsView() {
             section={settingsSection}
             projectId={active?.id}
             onSectionChange={setSettingsSection}
+            onAssignPluginCapabilities={() => {
+              setSettingsSection(null);
+              if (placementOf(placements, "agents") === "closed") {
+                setPlacement("agents", "floating");
+              }
+            }}
             onClose={() => setSettingsSection(null)}
           />
         ) : active ? (

frontend/src/features/settings/SettingsView.tsx

@@ -50,6 +50,7 @@ interface SettingsViewProps {
   section: SettingsSection;
   projectId?: string;
   onSectionChange: (section: SettingsSection) => void;
+  onAssignPluginCapabilities?: () => void;
   onClose: () => void;
 }
 
@@ -57,6 +58,7 @@ export function SettingsView({
   section,
   projectId,
   onSectionChange,
+  onAssignPluginCapabilities,
   onClose,
 }: SettingsViewProps) {
   return (
@@ -99,7 +101,10 @@ export function SettingsView({
           ) : section === "deployment" ? (
             <DeploymentSettings />
           ) : section === "plugins" ? (
-            <PluginsPanel projectId={projectId} />
+            <PluginsPanel
+              projectId={projectId}
+              onAssignAgents={onAssignPluginCapabilities}
+            />
           ) : (
             // No `onSessionEnded`: the desktop app hosts the server and is never
             // itself a paired device, so it cannot revoke its own session.