fix: add disposed guard to MCP manager and guard unregister on pending connections

src/features/skill-mcp-manager/cleanup.ts

@@ -81,7 +81,7 @@ async function cleanupIdleClients(state: SkillMcpManagerState): Promise<void> {
     }
   }
 
-  if (state.clients.size === 0) {
+  if (state.clients.size === 0 && state.pendingConnections.size === 0) {
     stopCleanupTimer(state)
     unregisterProcessCleanup(state)
   }
@@ -119,7 +119,7 @@ export async function disconnectSession(state: SkillMcpManagerState, sessionID:
     state.pendingConnections.delete(key)
   }
 
-  if (state.clients.size === 0) {
+  if (state.clients.size === 0 && state.pendingConnections.size === 0) {
     stopCleanupTimer(state)
     unregisterProcessCleanup(state)
   }
@@ -127,6 +127,7 @@ export async function disconnectSession(state: SkillMcpManagerState, sessionID:
 
 export async function disconnectAll(state: SkillMcpManagerState): Promise<void> {
   state.shutdownGeneration++
+  state.disposed = true
   stopCleanupTimer(state)
   unregisterProcessCleanup(state)
 

src/features/skill-mcp-manager/connection-race.test.ts

@@ -81,6 +81,7 @@ function createState(): SkillMcpManagerState {
     idleTimeoutMs: 5 * 60 * 1000,
     shutdownGeneration: 0,
     inFlightConnections: new Map(),
+    disposed: false,
   }
 
   trackedStates.push(state)

src/features/skill-mcp-manager/connection.ts

@@ -15,6 +15,10 @@ export async function getOrCreateClient(params: {
 }): Promise<Client> {
   const { state, clientKey, info, config } = params
 
+  if (state.disposed) {
+    throw new Error(`MCP manager for "${info.sessionID}" has been shut down, cannot create new connections.`)
+  }
+
   const existing = state.clients.get(clientKey)
   if (existing) {
     existing.lastUsedAt = Date.now()

src/features/skill-mcp-manager/disconnect-cleanup.test.ts

@@ -26,6 +26,7 @@ function createState(): SkillMcpManagerState {
     idleTimeoutMs: 5 * 60 * 1000,
     shutdownGeneration: 0,
     inFlightConnections: new Map(),
+    disposed: false,
   }
 
   trackedStates.push(state)

src/features/skill-mcp-manager/manager.ts

@@ -18,6 +18,7 @@ export class SkillMcpManager {
     idleTimeoutMs: 5 * 60 * 1000,
     shutdownGeneration: 0,
     inFlightConnections: new Map(),
+    disposed: false,
   }
 
   private getClientKey(info: SkillMcpClientInfo): string {

src/features/skill-mcp-manager/types.ts

@@ -59,6 +59,7 @@ export interface SkillMcpManagerState {
   idleTimeoutMs: number
   shutdownGeneration: number
   inFlightConnections: Map<string, number>
+  disposed: boolean
 }
 
 export interface SkillMcpClientConnectionParams {