is it me or serve-mcp broken ?

[unkier]

here is a config.yml i'm trying to use :
`agents:

labgrid_expert:
type: claude_code
setting_sources: ["user", "project", "local"]
model: sonnet
environment: "/home/demon/devel/labgrid"
use_subscription: true
permission_mode: bypassPermissions
allowed_tools:
- Read
- Bash
- Glob
- Grep
system_prompt: |
You are a read-only Labgrid domain expert. You have access to the full
Labgrid source tree and can answer questions about:

    • Core API (Target, Resource, Driver, Strategy, Protocol)
    • Pytest integration (fixtures: target, env, strategy; markers)
    • Drivers: ShellDriver, SSHDriver, SerialDriver, PowerDriver,
      DigitalOutputDriver, USBStorageDriver, QEMUDriver, etc.
    • Resources: NetworkService, SerialPort, USBResource, RemotePlace
    • Strategies: ShellStrategy, BareboxStrategy, UBootStrategy
    • Environment files (.yaml) and resource/provider configuration
    • Exporter and coordinator (crossbar) setup
    • Helper utilities (labgridhelper, proxy usage)

  You must NEVER modify any files. Only read, search, and explain code.
  When answering, cite file paths and line numbers so the caller can
  cross-reference the source.`

running it: uv run agentpool serve-mcp site/examples/openwrt-experts-mcp/config.yml

At first, I got error messages about missing diskcache and pathvalidate. After installing it, I've got some other error messages:

ValueError: Functions with **kwargs are not supported as tools Traceback (most recent call last): File "/home/demon/devel/agentpool/src/agentpool_server/base.py", line 99, in start await self._start_async() File "/home/demon/devel/agentpool/src/agentpool_server/mcp_server/server.py", line 246, in _start_async await self._register_pool_tools() File "/home/demon/devel/agentpool/src/agentpool_server/mcp_server/server.py", line 135, in _register_pool_tools self.fastmcp.tool(annotations=tool_annotations)(tool_handler) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^ File "/home/demon/devel/agentpool/.venv/lib/python3.13/site-packages/fastmcp/server/providers/local_provider/decorators/tools.py", line 292, in tool return decorate_and_register(name_or_fn, name) File "/home/demon/devel/agentpool/.venv/lib/python3.13/site-packages/fastmcp/server/providers/local_provider/decorators/tools.py", line 288, in decorate_and_register tool_obj = self.add_tool(fn) File "/home/demon/devel/agentpool/.venv/lib/python3.13/site-packages/fastmcp/server/providers/local_provider/decorators/tools.py", line 66, in add_tool tool = Tool.from_function( tool, ...<13 lines>... auth=fmeta.auth, ) File "/home/demon/devel/agentpool/.venv/lib/python3.13/site-packages/fastmcp/tools/tool.py", line 212, in from_function return FunctionTool.from_function( ~~~~~~~~~~~~~~~~~~~~~~~~~~^ fn=fn, ^^^^^^ ...<13 lines>... auth=auth, ^^^^^^^^^^ ) ^ File "/home/demon/devel/agentpool/.venv/lib/python3.13/site-packages/fastmcp/tools/function_tool.py", line 202, in from_function parsed_fn = ParsedFunction.from_function(fn, exclude_args=metadata.exclude_args) File "/home/demon/devel/agentpool/.venv/lib/python3.13/site-packages/fastmcp/tools/function_parsing.py", line 84, in from_function raise ValueError( "Functions with **kwargs are not supported as tools" ) ValueError: Functions with **kwargs are not supported as tools

[phil65]

I will take a look, perhaps its caused by FastMCP version bump to 3.0?

[phil65]

Should be fixed on main now.

[unkier]

ok, so now just starting is standalone gives no error. Now I've connected it to my Claude code. "/mcp list" shows it as connected and green. But when I try to ask the agent to talk to it: "ask labgrid-expert about it's capabilities". It throws another error:

❯ ask labgrid-expert about it's capabilities

● labgrid-expert - ask_labgrid_expert (MCP)(prompt: "What are your capabilities? What can you help with? Please describe everything you can do, including any tools, features, and areas of expertise you have.")
  ⎿  Error: Error calling tool 'ask_labgrid_expert': Failed to parse system message: 2 validation errors for tagged-union[SystemMessage,HookStartedSystemMessage,StatusSystemMessage,CompactBoundarySystemMessage,HookProgressSystemMessage,Ho
     okResponseSystemMessage,TaskStartedSystemMessage,TaskNotificationSystemMessage,FilesPersistedSystemMessage]
     init.plugins.0
       Input should be a valid string [type=string_type, input_value={'name': 'pyright-lsp', '...cial/pyright-lsp/1.0.0'}, input_type=dict]
         For further information visit https://errors.pydantic.dev/2.12/v/string_type
     init.plugins.1
       Input should be a valid string [type=string_type, input_value={'name': 'clangd-lsp', 'p...icial/clangd-lsp/1.0.0'}, input_type=dict]
         For further information visit https://errors.pydantic.dev/2.12/v/string_type

● The labgrid-expert MCP tool is available but it's returning a configuration error when called. The issue is a parsing error in the MCP server's system message configuration:

  Failed to parse system message: 2 validation errors
  - init.plugins.0: Input should be a valid string, got dict {'name': 'pyright-lsp', ...}
  - init.plugins.1: Input should be a valid string, got dict {'name': 'clangd-lsp', ...}

  It looks like the labgrid-expert server's plugin configuration expects plugin entries to be strings (e.g. "pyright-lsp") but they're currently defined as objects/dicts with name and other fields. This is likely a configuration issue in
  the MCP server setup that needs to be fixed on the server side.

  You may need to check the labgrid-expert MCP server configuration and update the plugin definitions to match the expected format.

[phil65]

ok, thx. I will take another look soon.

[phil65]

Try again on latest main, should be fixed now (was caused by my underlying claude agent sdk fork, which is much stricter when it comes to typing/validation then the official one)

[unkier]

Good, we are moving forward:) new error:

❯ ask labgrid-expert about it's capabilities

● labgrid-expert - ask_labgrid_expert (MCP)(prompt: "What are your capabilities? Please describe what you can do, what tools and knowledge you have access to, and what kinds of tasks you can help with.")
  ⎿  Error: 1 validation error for ClaudeCodeServerInfo
     account.organization
       Extra inputs are not permitted [type=extra_forbidden, input_value='SecretCompany', input_type=str]
         For further information visit https://errors.pydantic.dev/2.12/v/extra_forbidden

● The labgrid-expert MCP server returned an error:

  1 validation error for ClaudeCodeServerInfo
  account.organization
    Extra inputs are not permitted [type=extra_forbidden, input_value='SecretCompany', input_type=str]

  This looks like a configuration/validation issue on the server side — the ClaudeCodeServerInfo model doesn't accept an organization field, but one is being passed ('SecretCompany'). This is a Pydantic v2 validation error in the MCP server
  code.

  To fix this, the labgrid-expert MCP server would need to either:
  1. Add organization as an accepted field in its ClaudeCodeServerInfo model, or
  2. Use model_config = ConfigDict(extra="allow") to permit extra fields, or
  3. The calling configuration needs to stop sending the organization field.

  Would you like me to look into the server's configuration or source code to help resolve this?

[phil65]

great thanks. should also be fixed now. Thanks for debugging :D

[unkier]

Works like a charm:) Thanks for a quick fix and for this amazing project!