How do I pass authorization header to LlmAgent tool?

[matino]

I have an instance that has a Runner object as a dependency. I want to pass the request "authorization" header value to the runner agent tool. As I understand, the correct way is to do it via session service (per #267). However, this doesn't work when I prefix the key with temp: (since I don't want to persist tokens).

        state_changes = {
            "temp:token": "<my token>",
        }
        actions_with_update = EventActions(state_delta=state_changes)
        system_event = Event(
            invocation_id="inv_login_update",
            author="system",  # Or 'agent', 'tool' etc.
            actions=actions_with_update,
        )

        await self.runner.session_service.append_event(session, system_event)

If I change the key from temp:token to user:token, the state is visible in the LlmAgent tool inside the ToolContext state.

Can somebody suggest a better approach?

[sindrigunnars]

I agree that the temp session key is fairly misleading. The way I've done this is just to make it user: specific. You could do some redis acrobatics with TTL to have it truly temporary or even write an empty value to it in the agent when you have retrieved it.

Let me know if you have any other suggestions/fixed I may have missed.

[matino]

I think another option would be to use the credential service. The Runner instance could call save_credentials, then the LLM tool could call load_credentials with tool_context._invocation_context.credential_service.load_credential(...). That's not super clean, but I guess it's more secure than persisting the token in the session service (even if only for a short while).

[sindrigunnars]

But does this solve the problem in the context of MCP tools?

[matino]

But does this solve the problem in the context of MCP tools?

I haven't used MCP tools, so can't really tell :/

[seanzhou1023]

the key prefixed with temp: won't be added to the session state. One thing you can do is that each time your tool read it your tool can remove it from the session state.

[seanzhou1023]

feel free to reopen if the above suggestion still doesn't work for you.

[matino]

@seanzhou1023 Could you please help with reviewing/merging #1829? It would really help to use credential service for secrets instead of session service 🙏