Output Validator

Before delivering any report or summary: define what a valid output looks like, generate, then verify the output against that spec.

When to use

Any time an agent produces a summary over source data: status reports, feature trackers, project dashboards, analysis outputs. Run this before handing off to the user.

Phase 1 — Pre-generation spec

Before pulling data or rendering output, answer these three questions and write the answers as a short checklist:

1. What counts reconcile? Name the summary metric and how it should relate to the detail rows. Example: "Released + In Development + Ready to Release = Total features."
2. What exceptions must always surface? Name the categories that cannot be buried in detail regardless of the headline. Examples: security issues, blockers, items past their target date, status contradictions (a critical item marked done while work is open).
3. What does an accurate headline look like? Define what the top-line metric (% complete, count, status) must reflect. Example: "99% complete is only accurate if no open security issues or blockers exist in the detail."

This checklist is the validation spec. Keep it visible — it is the external anchor for Phase 2.

Phase 2 — Post-generation checks

After the report is generated, run each check explicitly against the spec from Phase 1:

Check 1 — Number reconciliation Add up the detail rows and compare to the summary counts. Quote both. If they differ, state the discrepancy and correct the summary before delivering.

Check 2 — Exception surfacing Scan every detail row for the exception categories defined in Phase 1. List each hit explicitly — name, status, and why it matters. If any exception is present but absent from the summary or headline, flag it as a divergence.

Check 3 — Headline accuracy Given the exceptions found in Check 2, does the headline still hold? If a security issue, blocker, or overdue item exists in the detail, the headline must acknowledge it — or be revised to accurately represent the actual state.

Output

If all checks pass: state output-validator: clean then deliver.

If any check fails: state the divergence, revise the affected section, then re-run the failed check before delivering.

Usage in claude.ai / Project instructions

This skill has no sub-skills and works in any single-model environment. To use in claude.ai without Claude Code: paste the content of this skill (below the frontmatter) into your Project's custom instructions. The agent will follow the two-phase protocol for any report task in that project.