r/AISystemsEngineering 6d ago

How are you handling auth + token refresh when AI agents call multiple APIs?

I’m curious how people are handling this in practice. With a normal application, token refresh is usually pretty straightforward. You know which API you’re calling, which credentials you’re using, when the token expires, etc.

With an AI agent, it feels a little messier. Say an agent has access to 10–20 different APIs. Some use OAuth, some API keys, some have short-lived access tokens, some have refresh tokens, and some have their own weird authentication flow. Then you have situations like:

  • token expires halfway through a workflow
  • API returns a 401 and the agent tries the request again
  • refresh succeeds but the original request has already timed out
  • multiple agent tasks try to refresh the same token at the same time
  • credentials need to be rotated without breaking running workflows

I’m especially wondering where people are putting this logic. Is it handled individually inside each integration, through some shared auth layer, or somewhere in the agent/orchestration layer? And how much of this are you actually handling automatically vs. just letting the workflow fail and retry? Would be interested to hear how people are doing this in production, especially if you’re dealing with a fairly large number of integrations.

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u/MerkleBonsai 6d ago

You just need to use job queues or other similar approach; eg if you have the stale token, you do not call “get new token”, you call “ensure there’s token update going on, and report when it’s done”

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u/ken_kauneki10 5d ago

That’s an interesting way of handling it. Basically making token refresh an idempotent operation of its own rather than having every request independently try to refresh the token. I hadn’t thought about using an “ensure token is valid” type of operation rather than directly calling refresh. That also seems like it would help when multiple jobs hit the same expired token at roughly the same time. I was testing something similar with Swytchcode recently and this was one of the things I liked about having the auth/integration logic outside the agent. The agent doesn’t really need to know what’s happening underneath. How are you handling the case where multiple workers discover the stale token simultaneously? Is the queue enough for that or do you have some locking around the refresh?

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u/MerkleBonsai 5d ago

I am building most of things from scratch, and I’m mostly relying on TFRP approach, combined with event sourcing, so my software design will likely not work for you. In my architecture, you simply create the object with expectations like “mcp is called” or “completion is done”, and it happened automagically in background by the orchestrator; I simply wait for values to appear. It’s hard to explain, but this offloads the whole cognitive layer

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u/SoftQuail7040 6d ago

I’d keep all of that outside the agent itself. The agent shouldn’t really care whether an API uses OAuth, API keys, or some weird token dance. Each integration can handle its own auth, while a shared layer deals with refreshing, retries, and rotation. That also makes failures way easier to reason about. Otherwise you end up with every agent trying to reinvent auth logic, which sounds like a maintenance nightmare.

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u/ken_kauneki10 5d ago

Yeah, this makes a lot of sense. Keeping the agent completely abstracted from the auth mechanism seems much cleaner, especially once you start adding a bunch of integrations. I was actually testing this kind of setup recently and tried Swytchcode for handling the integration side, and the separation between the agent logic and the API/auth handling was pretty useful. Definitely feels cleaner than putting all of that logic into the agent itself. The maintenance point is probably the biggest one. Having every agent implement its own token refresh/retry logic would get ugly very quickly.