Quality Checker Loop
Use a separate checker to test whether an agent output follows the method, evidence, and safety rules.
What this Loop Engineering template does
Evaluate an agent output against an explicit quality checklist and return pass, fail, or partial with reasons.
Treat the original goal, validation evidence, boundaries, and method checklist as the source of truth. The checker should be allowed to reject the result.
When to use it
When not to use it
Validation checks
Boundaries & stop rule
Copy the loop prompt
/goal Evaluate an agent output against an explicit quality checklist and return pass, fail, or partial with reasons.Task type: CustomTarget tool: Claude CodeWork toward this goal until all validation checks pass or the stop rule is reached.Design hypothesis:This quality checker loop can produce a safer result if the scope stays narrow, validation is explicit, and a checker can reject shortcut work.Smallest useful run:Run one bounded pass on the newest relevant signal before expanding scope or adding a schedule.Loop cycle:1. Discovery — Read the latest signal for this template before acting: CI output, issue detail, review comment, dataset report, or content brief.2. Handoff — Hand the work to one agent in an isolated branch, worktree, or clearly scoped session. Keep final approval with a human.3. Verification — Use an independent review pass to confirm the result, inspect the diff or artifact, and reject shortcut work.4. Persistence — Save a short run note with the signal reviewed, actions taken, validation result, and next recommended step.5. Scheduling — Run manually until the loop is reliable; only then consider a scheduled or event-triggered run.Context:Treat the original goal, validation evidence, boundaries, and method checklist as the source of truth. The checker should be allowed to reject the result.Validation:Checker has access to the goal and expected evidenceEvery checklist item is answeredShortcuts and missing evidence are called outResult is marked pass, fail, or partialValidation evidence:Record the original signal, checks run, final result, changed files or artifacts, and any checker rejection.Independent checker:Use an independent review pass to confirm the result, inspect the diff or artifact, and reject shortcut work.Boundaries:Do not approve work only because it sounds plausibleDo not ignore missing validation evidenceDo not let the maker agent decide the final quality resultDo not turn partial into pass without a reasonStop rule:Stop after one complete review and return the decision with reasons.Maximum iterations: 2Budget:Example only: stop before exceeding the agreed per-run token budget.Human approval:Required before merge, deploy, delete, purchase, or external communication.Fallback:If evidence is missing, mark the result partial or fail and ask for the missing evidence.Loop Validation Log:- Hypothesis: This quality checker loop can produce a safer result if the scope stays narrow, validation is explicit, and a checker can reject shortcut work.- Smallest useful run: Run one bounded pass on the newest relevant signal before expanding scope or adding a schedule.- Expected evidence: Record the original signal, checks run, final result, changed files or artifacts, and any checker rejection.- Actual evidence: [fill in after the run]- Passed? [yes / no / partial]- Feedback: After the run, note what the loop learned, what failed, and what should change before the next pass.- Next step: [stop / adjust the loop / run the next pass]Do not delete tests, bypass checks, or modify unrelated files just to satisfy the validation condition. If blocked, stop and summarize the blocker, attempted fixes, and recommended next action.
Failure modes to watch
Review receipt
This is a bounded review exercise for the template, not a claim about a production deployment.
Scenario
A content loop reports completion after adding citations, but two links do not support the adjacent claims and one limitation is omitted.
Baseline evidence
The checker receives the stated acceptance criteria, rendered page, source list, changed claims, link targets, and maker report without permission to repair the work itself.
Validation result
It returns Pass for rendering, Partial for the missing limitation, and Stop for the unsupported claims, with exact locations and the evidence required for reconsideration.
Shortcut rejected
Counting citations or words as a quality score is rejected because a linked page can be irrelevant and a longer article can still be low value.
Human gate
A human chooses whether the maker should revise, whether disputed evidence is acceptable, and whether the work can advance after an independent recheck.
Loop Engineering FAQ
Yes, but keep it separate from the maker and give it explicit rejection criteria. For high-risk work, a human still owns the final decision.