MCP Wikipedia Server

from __future__ import annotations from collections.abc import Mapping, Sequence from typing import Any from langgraph._internal._constants import RESERVED from langgraph.channels.base import BaseChannel from langgraph.managed.base import ManagedValueMapping from langgraph.pregel._read import PregelNode from langgraph.types import All def validate_graph( nodes: Mapping[str, PregelNode], channels: dict[str, BaseChannel], managed: ManagedValueMapping, input_channels: str | Sequence[str], output_channels: str | Sequence[str], stream_channels: str | Sequence[str] | None, interrupt_after_nodes: All | Sequence[str], interrupt_before_nodes: All | Sequence[str], ) -> None: for chan in channels: if chan in RESERVED: raise ValueError(f"Channel name '{chan}' is reserved") for name in managed: if name in RESERVED: raise ValueError(f"Managed name '{name}' is reserved") subscribed_channels = set[str]() for name, node in nodes.items(): if name in RESERVED: raise ValueError(f"Node name '{name}' is reserved") if isinstance(node, PregelNode): subscribed_channels.update(node.triggers) if isinstance(node.channels, str): if node.channels not in channels: raise ValueError( f"Node {name} reads channel '{node.channels}' " f"not in known channels: '{repr(sorted(channels))[:100]}'" ) else: for chan in node.channels: if chan not in channels and chan not in managed: raise ValueError( f"Node {name} reads channel '{chan}' " f"not in known channels: '{repr(sorted(channels))[:100]}'" ) else: raise TypeError( f"Invalid node type {type(node)}, expected PregelNode or NodeBuilder" ) for chan in subscribed_channels: if chan not in channels: raise ValueError( f"Subscribed channel '{chan}' not " f"in known channels: '{repr(sorted(channels))[:100]}'" ) if isinstance(input_channels, str): if input_channels not in channels: raise ValueError( f"Input channel '{input_channels}' not " f"in known channels: '{repr(sorted(channels))[:100]}'" ) if input_channels not in subscribed_channels: raise ValueError( f"Input channel {input_channels} is not subscribed to by any node" ) else: for chan in input_channels: if chan not in channels: raise ValueError( f"Input channel '{chan}' not in '{repr(sorted(channels))[:100]}'" ) if all(chan not in subscribed_channels for chan in input_channels): raise ValueError( f"None of the input channels {input_channels} " f"are subscribed to by any node" ) all_output_channels = set[str]() if isinstance(output_channels, str): all_output_channels.add(output_channels) else: all_output_channels.update(output_channels) if isinstance(stream_channels, str): all_output_channels.add(stream_channels) elif stream_channels is not None: all_output_channels.update(stream_channels) for chan in all_output_channels: if chan not in channels: raise ValueError( f"Output channel '{chan}' not " f"in known channels: '{repr(sorted(channels))[:100]}'" ) if interrupt_after_nodes != "*": for n in interrupt_after_nodes: if n not in nodes: raise ValueError(f"Node {n} not in nodes") if interrupt_before_nodes != "*": for n in interrupt_before_nodes: if n not in nodes: raise ValueError(f"Node {n} not in nodes") def validate_keys( keys: str | Sequence[str] | None, channels: Mapping[str, Any], ) -> None: if isinstance(keys, str): if keys not in channels: raise ValueError(f"Key {keys} not in channels") elif keys is not None: for chan in keys: if chan not in channels: raise ValueError(f"Key {chan} not in channels")