[PerUserRetrieval] How to pass dynamic config values to chain?

[ykoitzsch]

My current setup is a bit different from what is shown in tutorials and I am not sure how to adapt to make it work. I'd like to pass down a config object that holds the tenant_id included in the user_auth_token.

async def per_req_config_modifier(config: Dict, request: Request) -> Dict:
    user = await authenticate_user(request)
    config["configurable"] = {}
    config["configurable"]["search_kwargs"] = {
        "k": 6, "filter": {"tenant_id": {"$eq": user.id}}}
    return config


add_routes(
    app,
    main_chain,
    path="/copilot/main",
    per_req_config_modifier=per_req_config_modifier
)

The "main chain" is an agentic conversational chain:

agent_executor = AgentExecutor(
    agent=agent, tools=tools, verbose=True, return_intermediate_steps=True
)

main_chain= agent_executor.with_types(
    input_type=Input, output_type=Output
)

One of the tools that requires this dynamic config object:

class DocumentsRetriever():

    def __init__(self):
        self.document_prompt = PromptTemplate.from_template(
            "dummy prompt"
        )
        self._retriever = None
        self._tool = None
        self._tenant_id = None

    @property
    def retriever(self):
        if not self._retriever:
            self._retriever = database.documents_db.as_retriever(
                search_kwargs={"k": 6, "filter": {
                    "tenant_id": {"$eq": self._tenant_id}}}
            )
        return self._retriever

    @property
    def tool(self):
        if not self._tool:
            self._tool = create_retriever_tool(
                self.retriever.configurable_fields(
                    search_kwargs=ConfigurableField(
                        id="search_kwargs",
                        name="Search Kwargs",
                        description="The search kwargs to use",
                    )
                ),
                "search_documents",
                "Searches documents for relevant information.",
                document_prompt=self.document_prompt,
            )
        return self._tool


documents_retriever = DocumentsRetriever()

how can I pass the dynamic config of {"k": 6, "filter": {"tenant_id": {"$eq": user.id}}}

to this DocumentsRetriever class, overriding the currently used search_kwargs. Any input is appreciated!