feat(skill-mcp): add auto-reconnect retry on "Not connected" errors

- Added withOperationRetry<T>() helper method that retries operations up to 3 times
- Catches "Not connected" errors (case-insensitive)
- Cleans up stale client before retry
- Modified callTool, readResource, getPrompt to use retry logic
- Added tests for retry behavior (3 new test cases)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

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

@@ -502,4 +502,110 @@ describe("SkillMcpManager", () => {
       )
     })
   })
+
+  describe("operation retry logic", () => {
+    it("should retry operation when 'Not connected' error occurs", async () => {
+      // #given
+      const info: SkillMcpClientInfo = {
+        serverName: "retry-server",
+        skillName: "retry-skill",
+        sessionID: "session-retry-1",
+      }
+      const context: SkillMcpServerContext = {
+        config: {
+          url: "https://example.com/mcp",
+        },
+        skillName: "retry-skill",
+      }
+
+      // Mock client that fails first time with "Not connected", then succeeds
+      let callCount = 0
+      const mockClient = {
+        callTool: mock(async () => {
+          callCount++
+          if (callCount === 1) {
+            throw new Error("Not connected")
+          }
+          return { content: [{ type: "text", text: "success" }] }
+        }),
+        close: mock(() => Promise.resolve()),
+      }
+
+      // Spy on getOrCreateClientWithRetry to inject mock client
+      const getOrCreateSpy = spyOn(manager as any, "getOrCreateClientWithRetry")
+      getOrCreateSpy.mockResolvedValue(mockClient)
+
+      // #when
+      const result = await manager.callTool(info, context, "test-tool", {})
+
+      // #then
+      expect(callCount).toBe(2) // First call fails, second succeeds
+      expect(result).toEqual([{ type: "text", text: "success" }])
+      expect(getOrCreateSpy).toHaveBeenCalledTimes(2) // Called twice due to retry
+    })
+
+    it("should fail after 3 retry attempts", async () => {
+      // #given
+      const info: SkillMcpClientInfo = {
+        serverName: "fail-server",
+        skillName: "fail-skill",
+        sessionID: "session-fail-1",
+      }
+      const context: SkillMcpServerContext = {
+        config: {
+          url: "https://example.com/mcp",
+        },
+        skillName: "fail-skill",
+      }
+
+      // Mock client that always fails with "Not connected"
+      const mockClient = {
+        callTool: mock(async () => {
+          throw new Error("Not connected")
+        }),
+        close: mock(() => Promise.resolve()),
+      }
+
+      const getOrCreateSpy = spyOn(manager as any, "getOrCreateClientWithRetry")
+      getOrCreateSpy.mockResolvedValue(mockClient)
+
+      // #when / #then
+      await expect(manager.callTool(info, context, "test-tool", {})).rejects.toThrow(
+        /Failed after 3 reconnection attempts/
+      )
+      expect(getOrCreateSpy).toHaveBeenCalledTimes(3) // Initial + 2 retries
+    })
+
+    it("should not retry on non-connection errors", async () => {
+      // #given
+      const info: SkillMcpClientInfo = {
+        serverName: "error-server",
+        skillName: "error-skill",
+        sessionID: "session-error-1",
+      }
+      const context: SkillMcpServerContext = {
+        config: {
+          url: "https://example.com/mcp",
+        },
+        skillName: "error-skill",
+      }
+
+      // Mock client that fails with non-connection error
+      const mockClient = {
+        callTool: mock(async () => {
+          throw new Error("Tool not found")
+        }),
+        close: mock(() => Promise.resolve()),
+      }
+
+      const getOrCreateSpy = spyOn(manager as any, "getOrCreateClientWithRetry")
+      getOrCreateSpy.mockResolvedValue(mockClient)
+
+      // #when / #then
+      await expect(manager.callTool(info, context, "test-tool", {})).rejects.toThrow(
+        "Tool not found"
+      )
+      expect(getOrCreateSpy).toHaveBeenCalledTimes(1) // No retry
+    })
+  })
 })

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

@@ -415,9 +415,10 @@ export class SkillMcpManager {
     name: string,
     args: Record<string, unknown>
   ): Promise<unknown> {
-    const client = await this.getOrCreateClientWithRetry(info, context.config)
-    const result = await client.callTool({ name, arguments: args })
-    return result.content
+    return this.withOperationRetry(info, context.config, async (client) => {
+      const result = await client.callTool({ name, arguments: args })
+      return result.content
+    })
   }
 
   async readResource(
@@ -425,9 +426,10 @@ export class SkillMcpManager {
     context: SkillMcpServerContext,
     uri: string
   ): Promise<unknown> {
-    const client = await this.getOrCreateClientWithRetry(info, context.config)
-    const result = await client.readResource({ uri })
-    return result.contents
+    return this.withOperationRetry(info, context.config, async (client) => {
+      const result = await client.readResource({ uri })
+      return result.contents
+    })
   }
 
   async getPrompt(
@@ -436,9 +438,53 @@ export class SkillMcpManager {
     name: string,
     args: Record<string, string>
   ): Promise<unknown> {
-    const client = await this.getOrCreateClientWithRetry(info, context.config)
-    const result = await client.getPrompt({ name, arguments: args })
-    return result.messages
+    return this.withOperationRetry(info, context.config, async (client) => {
+      const result = await client.getPrompt({ name, arguments: args })
+      return result.messages
+    })
+  }
+
+  private async withOperationRetry<T>(
+    info: SkillMcpClientInfo,
+    config: ClaudeCodeMcpServer,
+    operation: (client: Client) => Promise<T>
+  ): Promise<T> {
+    const maxRetries = 3
+    let lastError: Error | null = null
+
+    for (let attempt = 1; attempt <= maxRetries; attempt++) {
+      try {
+        const client = await this.getOrCreateClientWithRetry(info, config)
+        return await operation(client)
+      } catch (error) {
+        lastError = error instanceof Error ? error : new Error(String(error))
+        const errorMessage = lastError.message.toLowerCase()
+
+        if (!errorMessage.includes("not connected")) {
+          throw lastError
+        }
+
+        if (attempt === maxRetries) {
+          throw new Error(
+            `Failed after ${maxRetries} reconnection attempts: ${lastError.message}`
+          )
+        }
+
+        const key = this.getClientKey(info)
+        const existing = this.clients.get(key)
+        if (existing) {
+          this.clients.delete(key)
+          try {
+            await existing.client.close()
+          } catch { /* process may already be terminated */ }
+          try {
+            await existing.transport.close()
+          } catch { /* transport may already be terminated */ }
+        }
+      }
+    }
+
+    throw lastError || new Error("Operation failed with unknown error")
   }
 
   private async getOrCreateClientWithRetry(