runtime

The base ASGI user protocol

Runtime context passed to graph builder factories within the Agent Server.

Requires version 0.7.30 or later of the agent server.

The server calls your graph factory in multiple contexts: executing runs, reading state, fetching schemas, and more. ServerRuntime provides the authenticated user, store, and access context for every call. Use .execution_runtime to narrow to the execution variant and access context.

Example — conditionally initialize MCP tools only during execution:

import contextlib
from dataclasses import dataclass

from langchain.agents import create_agent
from langgraph_sdk.runtime import ServerRuntime
from my_agent import connect_mcp, disconnect_mcp

@dataclass
class MyCtx:
    mcp_endpoint: str

_readonly_agent = create_agent("anthropic:claude-3-5-haiku", tools=[])

@contextlib.asynccontextmanager
async def my_factory(runtime: ServerRuntime[MyCtx]):
    if ert := runtime.execution_runtime:
        # Only connect to MCP servers for actual runs.
        # Schema / graph introspection calls skip this.
        user_id = runtime.ensure_user().identity
        mcp_tools = await connect_mcp(ert.context.mcp_endpoint, user_id)
        yield create_agent("anthropic:claude-3-5-haiku", tools=mcp_tools)
        await disconnect_mcp()
    else:
        yield _readonly_agent

Example — simple factory that ignores context:

from langgraph_sdk.runtime import ServerRuntime

def build_graph(user: BaseUser) -> CompiledGraph:
    ...

async def my_factory(runtime: ServerRuntime) -> CompiledGraph:
    # No generic needed if you don't use context.
    return build_graph(runtime.ensure_user())