Engineering

Completion Promise Loop

Make the agent promise completion against explicit evidence, not vibes and a cheerful summary.

Use when

A coding agent keeps declaring work done after the easy part, or a feature has multiple acceptance criteria that must be proven before handoff.

Cadence

For scoped implementation tasks where half-finished output is the main risk

Verification

Every acceptance criterion is checked with tests, browser evidence, logs, screenshots, or a clear blocker report before the agent stops.

Advanced spec

Structured loop spec

Field	Value
Name	Completion Promise Loop
Category	Engineering
Trigger	For scoped implementation tasks where half-finished output is the main risk
Objective	Make the agent promise completion against explicit evidence, not vibes and a cheerful summary.
Allowed inputs	Relevant files, source notes, logs, tests, screenshots, metrics, or task state for this loop
Allowed actions	Write the acceptance criteria as a checklist before implementation starts.; Have the agent restate the done contract, allowed files, verification commands, and stop conditions.; Let the agent implement one slice, then immediately run the nearest proof: tests, browser check, lint, logs, screenshot, or fixture comparison.; After each failure or uncovered criterion, repair and re-run the relevant proof instead of moving on to unrelated cleanup.; Stop only when every criterion is proven, the budget is exhausted, or a blocker is returned with exact evidence and the next human decision.
Verification	Every acceptance criterion is checked with tests, browser evidence, logs, screenshots, or a clear blocker report before the agent stops.
Stop condition	Stop when the verifier passes, the budget is exhausted, no progress is made, a blocker appears, or approval is required.
Budget	Set a time, turn, token, retry, file, or dollar cap before running the loop.
Approval boundary	Human approval required before publishing, sending, deleting, spending, changing accounts, touching production, or making reputational/legal/financial commitments.
Safe output	Pull request, patch, report, or evidence log
Works with	Claude Code, OpenAI Codex, Cursor, Gemini CLI, any tool-using coding agent

Runbook

Steps

Write the acceptance criteria as a checklist before implementation starts.
Have the agent restate the done contract, allowed files, verification commands, and stop conditions.
Let the agent implement one slice, then immediately run the nearest proof: tests, browser check, lint, logs, screenshot, or fixture comparison.
After each failure or uncovered criterion, repair and re-run the relevant proof instead of moving on to unrelated cleanup.
Stop only when every criterion is proven, the budget is exhausted, or a blocker is returned with exact evidence and the next human decision.

Copy prompt

Prompt

Run the Completion Promise Loop. Restate the acceptance criteria, allowed scope, verification commands, and stop conditions before editing. Implement in small slices. After each meaningful change, run the closest proof for the relevant criterion: tests, browser check, lint, logs, screenshot, or fixture comparison. Keep a checklist of criteria and mark each as proven, failed, or blocked with evidence. Continue until every criterion is proven, the budget is exhausted, or a blocker requires human judgment. Return changed files, verification output, remaining risks, and any criteria not proven.

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