AI Systems Atlas

H-06Actor → Verifier

/harnesses/actor-verifier

One agent performs the task; another independently checks whether it actually succeeded.

Step-by-step walkthrough9 steps
  1. The actor takes the task…
  2. …and changes the environment: edits files, runs commands.
  3. A separate verifier inspects the outcome. It never edits.
  4. Checks run: tests pass, build passes, lint fails.
  5. FAIL — diagnostic detail travels with the verdict.
  6. Diagnosis turns the raw failure into a targeted retry.
  7. The actor fixes exactly what failed.
  8. Re-verify: all checks green.
  9. PASS. Execution and verification never shared a blind spot.
Key insight

Separating execution from verification is the single most reliable upgrade to an agent loop — especially when the verifier is grounded in tests, builds or other hard checks.

Failure mode

Shared blind spots: if both roles miss the same class of error, verification adds latency and false confidence, not reliability.

Further reading
RelatedGenerator–CriticCoding loopOutcome evals

Elsewhere in the atlas

Security →Evals →Context →Coding Agents →Tools →Ops →