FreeToken · industry guide

Designing an AI Agent That Can Survive a Free API Failure

A fallback is useful only when it preserves task state, respects credential boundaries and knows why the primary route failed.

Official sourcesPractical checklistHuman checked
Separate responsibilities

Keep the agent contract independent of one model API

  • Store the task state, tool schema, review rules and provider adapter separately. A narrow internal request contract lets the same task move between compatible routes without granting a model direct access to the scheduler or credential store.
  • Use different preferred and fallback routes for discovery and review roles. If both roles depend on one provider, one quota or authentication failure can silently remove the independent check.
Route by failure

Do not treat every unsuccessful request the same

  • Authentication failure should quarantine a credential, rate limiting should create a bounded cooldown, quota exhaustion may require a longer route change, and repeated timeouts should open a circuit only after a threshold. A malformed model response needs a schema retry or a different auditor, not an automatic API-key rotation.
  • Measure route health per role. A provider that answers a tiny canary may still perform poorly when asked for strict JSON auditing, so one blended health score can hide the failure mode.
Protect credentials

Automate route selection, not secret ownership

  • Models should never read, copy or create provider secrets. The runtime injects the credential into the outbound request and returns only the result. Keep platform operations keys separate from user Vault data and use one secret per provider so revocation stays narrow.
  • After a fallback, run a bounded canary before restoring the full queue. Preserve the failed job and evidence so an operator can distinguish a provider incident from a bad source or prompt.
Quick answers

Frequently asked questions

Can an AI agent automatically switch providers?

Yes, if the trigger is deterministic, the task contract is portable and the fallback is verified before full traffic resumes.

Should the model choose or rotate API keys?

No. Credential selection belongs to the trusted runtime, outside the model context.

Why keep separate Scout and Auditor routes?

It reduces the chance that one provider failure or shared model bias defeats both collection and review.

How this was made

AI assistance is disclosed; every factual claim was reviewed.

This guide uses the linked provider documentation to establish multi-provider and API-connected tool context. The routing, isolation and recovery recommendations are FreeToken's operational design, reviewed by a human editor rather than copied from those sources.