airflow.providers.common.ai.toolsets.langchain_bridge¶

Bridge pydantic-ai toolsets into LangChain tools.

This is the reverse of pydantic-ai’s upstream pydantic_ai.ext.langchain bridge. Upstream turns LangChain tools into a pydantic-ai toolset (LangChainToolset) so they can be used with common.ai’s AgentOperator. This module goes the other way: it turns a pydantic-ai AbstractToolset – such as common.ai’s SQLToolset, HookToolset, or MCPToolset – into a list of LangChain StructuredTool objects, so Airflow’s curated tools can be handed to a LangChain agent or chain.

Functions¶

airflow_toolset_to_langchain_tools(toolset, *[, deps])

Convert a pydantic-ai toolset into a list of LangChain StructuredTool objects.

Module Contents¶

airflow.providers.common.ai.toolsets.langchain_bridge.airflow_toolset_to_langchain_tools(toolset, *, deps=None)[source]¶

Convert a pydantic-ai toolset into a list of LangChain StructuredTool objects.

Each returned tool is backed by toolset.call_tool and carries the args_schema derived from the tool’s JSON schema, so a LangChain agent or chain can call it the same way it calls any native LangChain tool.

If a tool raises pydantic-ai’s ModelRetry (the bundled SQL toolsets do this to ask the model to correct its input, e.g. an unknown column), the bridge returns the retry message as the tool’s output so the model sees it and tries again. ModelRetry is a feed-the-model-and-retry signal, not a failure; returning it mirrors that and works regardless of how the agent handles tool errors. Raising instead would abort the run under create_agent’s default tool-error handling.

The toolset’s get_tools is invoked eagerly here to enumerate the tools.

Warning

The bridge does not hold a toolset session open across calls. get_tools and every call_tool each run under their own event loop, and pydantic-ai opens and tears the connection down around each one. For MCPToolset this means the server is reconnected on every tool call. That is fine for stateless tools (and for HTTP/SSE servers, modulo per-call latency), but an MCPServerStdio server, or any server that keeps state between calls, will lose that state because each call starts a fresh process/session.

Note

A pydantic-ai toolset is normally driven inside an agent run, where a live RunContext carries the model, usage, and message history. Outside an agent run there is no such context, so this bridge builds a minimal one with an inert placeholder model. The curated common.ai toolsets (SQLToolset, HookToolset, MCPToolset) ignore the context, so this works for them. A custom toolset that reads live run state (ctx.model, ctx.messages, ctx.usage) will not behave correctly when bridged standalone.

Parameters:

toolset (pydantic_ai.toolsets.abstract.AbstractToolset[Any]) – The pydantic-ai toolset to convert.
deps (Any) – Optional dependency object exposed to the toolset as ctx.deps. Defaults to None.

Returns:

A list of LangChain StructuredTool objects, one per tool in the toolset.

Return type:

list[langchain_core.tools.StructuredTool]