CherryHQ/cherry-studio · error · McpError

MethodNotFound

MethodNotFound

Error message

Unknown tool: ${name}

What it means

The memory MCP server's CallTool handler reaches the `default` switch branch and throws McpError MethodNotFound with the offending tool name. This means the requested tool name does not match any handled case (`create_entities`, `create_relations`, `add_observations`, `delete_entities`, `delete_observations`, `delete_relations`, `read_graph`, `search_nodes`, `open_nodes`). It is a protocol-level error distinct from InvalidParams.

Source

Thrown at src/main/ai/mcp/servers/memory.ts:694

            }
          case 'search_nodes':
            if (typeof args.query !== 'string') {
              throw new McpError(ErrorCode.InvalidParams, `Invalid arguments for ${name}: 'query' string is required.`)
            }
            return {
              content: [{ type: 'text', text: JSON.stringify(await manager.searchNodes(args.query), null, 2) }]
            }
          case 'open_nodes':
            if (!args.names || !Array.isArray(args.names)) {
              throw new McpError(ErrorCode.InvalidParams, `Invalid arguments for ${name}: 'names' array is required.`)
            }
            return {
              content: [
                { type: 'text', text: JSON.stringify(await manager.openNodes(args.names as string[]), null, 2) }
              ]
            }
          default:
            throw new McpError(ErrorCode.MethodNotFound, `Unknown tool: ${name}`)
        }
      } catch (error) {
        // Catch errors from manager methods (like entity not found) or other issues
        if (error instanceof McpError) {
          throw error // Re-throw McpErrors directly
        }
        logger.error(`Error executing tool ${name}:`, error as Error)
        // Throw a generic internal error for unexpected issues
        throw new McpError(
          ErrorCode.InternalError,
          `Error executing tool ${name}: ${error instanceof Error ? error.message : String(error)}`
        )
      }
    })
  }
}

export default MemoryServer

View on GitHub (pinned to 726446b54c)

Solutions

1. Call `tools/list` first and use only names it returns.
2. Check for typos and version mismatches between the client and the memory server.
3. If you renamed a tool, update all call sites and redeploy both ends.

Example fix

// before
{ name: "delete_entity" /* typo */ }
// after
{ name: "delete_entities" }

const MEMORY_TOOLS = new Set([
  'create_entities','create_relations','add_observations',
  'delete_entities','delete_observations','delete_relations',
  'read_graph','search_nodes','open_nodes'
])
function assertMemoryTool(name: string) {
  if (!MEMORY_TOOLS.has(name)) throw new Error(`Unknown memory tool: ${name}. Call tools/list.`)
}

const isMemoryTool = (name: string): boolean => MEMORY_TOOLS.has(name)

try {
  assertMemoryTool(name)
  await client.callTool({ name, arguments })
} catch (e) {
  if (e instanceof McpError && e.code === ErrorCode.MethodNotFound) {
    // refresh tools/list, fix the name, do NOT retry blindly
  }
  throw e
}

When it happens

Trigger: Calling a tool name the server does not register: a typo, a deprecated name, or a name from a different server routed here by mistake.

Common situations: Version skew between client and server (tool renamed/removed); a typo in the tool name; the model hallucinates a tool name; routing a call to the wrong MCP server.

Related errors

• MethodNotFound
• MethodNotFound
• ErrorCode.MethodNotFound
• MethodNotFound
• MethodNotFound

AI-assisted analysis of CherryHQ/cherry-studio@726446b54c (2026-08-12). Data as JSON: /api/errors/4f6d160834c451de. Report an issue: GitHub.