langgraph_agent_toolkit.core.mcp module

Configure MCP tools without importing the optional client at module load.

class langgraph_agent_toolkit.core.mcp.MCPServerConfig(*, transport='http', url=None, command=None, args=<factory>, headers=<factory>, headers_env=<factory>, env=<factory>, env_env=<factory>, mode='auto', timeout=30.0, tool_allowlist=None)[source][source]

Bases: BaseModel

Describe one operator-configured MCP server and its credentials.

Create a new model by parsing and validating input data from keyword arguments.

Raises [ValidationError][pydantic_core.ValidationError] if the input data cannot be validated to form a valid model.

self is explicitly positional-only to allow self as a field name.

Parameters:

  • transport (Literal['http', 'stdio'])

  • url (str | None)

  • command (str | None)

  • args (list[str])

  • headers (dict[str, SecretStr])

  • headers_env (dict[str, str])

  • env (dict[str, SecretStr])

  • env_env (dict[str, str])

  • mode (Literal['auto', 'legacy'])

  • timeout (Annotated[float, Gt(gt=0), _PydanticGeneralMetadata(allow_inf_nan=False)])

  • tool_allowlist (list[str] | None)

model_config = {'extra': 'forbid', 'hide_input_in_errors': True}

Configuration for the model, should be a dictionary conforming to [ConfigDict][pydantic.config.ConfigDict].

transport: Literal['http', 'stdio']
url: str | None
command: str | None
args: list[str]
headers: dict[str, SecretStr]
headers_env: dict[str, str]
env: dict[str, SecretStr]
env_env: dict[str, str]
mode: Literal['auto', 'legacy']
timeout: float
tool_allowlist: list[str] | None
validate_transport()[source][source]
Return type:

MCPServerConfig

langgraph_agent_toolkit.core.mcp.merge_tools(local_tools, extra_tools)[source][source]

Reject duplicate names before a graph can replace a tool silently.

Parameters:

  • local_tools (Sequence[BaseTool])

  • extra_tools (Sequence[BaseTool])

Return type:

list[BaseTool]

async langgraph_agent_toolkit.core.mcp.load_mcp_tools(servers, *, discovery_timeout=30.0)[source][source]

Discover namespaced tools. Each tool opens and closes its own connection context.

The SDK can share a connection between overlapping calls. No connection stays open after the last call exits. Restart the worker to refresh tool schemas.

Parameters:
Return type:

dict[str, list[BaseTool]]

async langgraph_agent_toolkit.core.mcp.configure_mcp_agents(executor, settings, *, rebuild_all=False)[source][source]

Build MCP graphs and optionally refresh all graphs for a new service lifespan.

Parameters:

  • executor (AgentExecutor)

  • settings (Settings)

  • rebuild_all (bool)

Return type:

None