| name | verification-loop |
| description | Use when a task spans more than a few steps or files — establishes a checkable definition of done, a verification cadence, and fresh-context verifier subagents before claiming completion. |
Verification Loop
Fable 5 builds its own checking harness on long tasks. Reproduce that explicitly.
1. Define "done" before starting
Write down (in your todo list or a scratch note) the binary checks that prove the task
is complete: which tests must pass, which command must produce which output, which
behavior must be observable. If the user's request doesn't define them, derive them
and state them in one sentence.
2. Verify on a cadence, not at the end
After each meaningful increment (a function implemented, a module refactored), run the
relevant real check immediately — the actual test command, the actual build. Never
batch all verification to the end of a long task; errors compound.
3. Fresh-context verification before completion claims
Before declaring a substantial task complete, dispatch a verifier subagent
(modelharness:verifier agent, or a general-purpose subagent given the
agents/verifier.md instructions). Give it: the original specification, the
definition-of-done checks, and the current diff (git diff output or changed file
list). A fresh context catches what you have rationalized away. Self-review is the
fallback only when subagents are unavailable.
4. Act on the verdict
If the verifier reports gaps: fix them, re-run the checks, re-verify. Only report
completion to the user when checks pass AND the verifier (or the checks themselves)
confirm it. Report any unverified remainder explicitly.
