langchain-ai/deepagents · error · ValueError

Server ' ' has type ' ' (remote) but also declares a…

Error message

Server '{server_name}' has type '{server_type}' (remote) but also declares a 'command' field. Remove 'command' or set `"type": "stdio"`.

What it means

A server whose resolved type is remote must not declare a 'command' field; that field is exclusive to stdio servers. The error tells the user to remove 'command' or switch the type to stdio.

Solutions

Remove the 'command' (and 'args') fields from the remote server entry
Set "type": "stdio" instead if the server is launched locally via command
Re-run validation after editing to confirm the config is clean

Example fix

// before
{"api": {"type": "http", "url": "https://mcp.example.com", "command": "npx"}}
// after
{"api": {"type": "http", "url": "https://mcp.example.com"}}

Defensive patterns

Strategy: validation

Validate before calling

def remote_entry_clean(cfg: dict) -> bool:
    if cfg.get('type') in ('http', 'sse', 'streamable-http'):
        return 'command' not in cfg
    return True

Try / catch

try:
    tools = await resolve_and_load_mcp_tools(config)
except ValueError as e:
    if "declares a 'command' field" in str(e):
        log.error('remote server must not define command: %s', e)
    raise

Prevention

When converting stdio -> remote, delete 'command'/'args' in the same edit
Strip transport-specific keys per type before passing configs
Lint MCP config files to forbid command+url together

When it happens

Trigger: Config mixing remote fields (type: http/sse + url) with a leftover 'command' key; converting a stdio entry to remote without deleting 'command'.

Common situations: Editing an existing stdio entry to point at a remote URL while keeping the launch command; merging two config files that define the same server differently.

Related errors

AI-assisted analysis of langchain-ai/deepagents@a1af029e6e (2026-08-29). Data as JSON: /api/errors/ae9b0c7ab86c0a15. Report an issue: GitHub.

Appendix: source

Thrown at libs/code/deepagents_code/mcp_tools.py:893

        raise TypeError(error_msg)

    server_type = _resolve_server_type(server_config)

    if server_type in _SUPPORTED_REMOTE_TYPES:
        if "url" not in server_config:
            error_msg = (
                f"Server '{server_name}' with type '{server_type}' "
                "missing required 'url' field"
            )
            raise ValueError(error_msg)

        if "command" in server_config:
            error_msg = (
                f"Server '{server_name}' has type '{server_type}' (remote) "
                "but also declares a 'command' field. Remove 'command' or "
                'set `"type": "stdio"`.'
            )
            raise ValueError(error_msg)

        headers = server_config.get("headers")
        if headers is not None and not isinstance(headers, dict):
            error_msg = f"Server '{server_name}' 'headers' must be a dictionary"
            raise TypeError(error_msg)

        if isinstance(headers, dict):
            for name, value in headers.items():
                if not isinstance(value, str):
                    error_msg = (
                        f"Server '{server_name}' header {name!r} must be "
                        f"a string, got {type(value).__name__}"
                    )
                    raise TypeError(error_msg)
    elif server_type == "stdio":
        if "command" not in server_config:
            error_msg = f"Server '{server_name}' missing required 'command' field"
            raise ValueError(error_msg)

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