# Verified Implementation > Implement a specification or set of tickets with evidence-gated completion, meaning captured test results, no false green, provenance-classified inputs, a traced final effect, and a clean-head pre-flight before handback. Use when implementing specified work that another identity will review independently, or when completion claims must be backed by executed evidence. - Skill: `tticom/verified-implementation` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tticom/verified-implementation` - Raw SKILL.md: https://api.skillmd.com/api/skills/tticom/verified-implementation/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tticom (https://skillmd.com/u/tticom) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/tticom/verified-implementation --- # Verified implementation Implement the work described by the user in the spec or tickets, and refuse to call it done until executed evidence says so. This skill governs how completion is claimed; it does not choose the design or widen the scope. **Prerequisite skills:** `code-review` Read the code-smell contract bundled with the `code-review` skill (in that skill's references) and apply it to your own changes. Reading that document is all this skill takes from `code-review`: do not perform a review, publish a verdict, or approve your own work. All AgentOps skills are installed together in one skills directory; if `code-review` is unavailable, stop and report `REQUIRED_SKILL_MISSING code-review`. Work test-first at pre-agreed seams where practical. Run type-checking regularly, single test files regularly, and the repository's mandated full test suite once at the end. A test command counts as run only after it finishes and its exit code and complete pass/fail/error/skip/xfail totals are captured. Starting it, collecting tests, running a smaller subset, relying on CI, or citing an earlier head does not count. Do not claim completion, success, green status, or review readiness when a required command was not run, did not finish, exited non-zero, or contains an unexpected failure or error. Report `FAILED`, `NOT_RUN`, `BLOCKED`, or `TIMED_OUT` literally and stop. Never add or widen skips or xfails merely to turn a failing aggregate green. Classify acceptance inputs as real-source, real-source extract, synthetic or mocked, or data-free. If the contract requires genuine-source evidence or forbids synthetic data, generated files, invented values, reconstructed inputs, and generator-authored expected output are not permitted substitutes. If the genuine source or independent oracle is unavailable, report `BLOCKED`; do not manufacture one. Where the change does not depend on real-world data (ordinary tooling, documentation, refactoring), controlled fixtures are appropriate: do not demand real-source evidence the change cannot use. ## Prove external data assumptions first Before implementing a heuristic that depends on an external library, file format, API, parser, or downstream schema, inspect representative live data at the exact production boundary. Use a disposable scratch probe outside tracked source, and record the library or runtime version, input provenance, command, and observed field values, types, units, cardinalities, and absent or degenerate cases. Derive the implementation rule from those observations and the authoritative contract. Documentation or intuition alone is insufficient when the behaviour is cheaply observable. Do not promote one observation into a universal heuristic. Exercise multiple genuine sources or cite a domain invariant, and test both sides of every chosen boundary. If live data contradicts the proposed design, stop and return the evidence rather than coding around the discrepancy. ## Trace the final production effect A passing helper or unit test does not complete a user-facing feature. Trace the changed value through each production handoff to its final consumer and user-visible artifact. Verify that the normal entrypoint consumes the new value, no later transformation drops or overwrites it, and the final output contains the exact required semantic result. Include a closest negative control that reaches the same path but must not produce that result. For pipeline, parser, conversion, serialization, or integration work whose behaviour depends on real data, run at least one genuine-source end-to-end acceptance test unless the contract explicitly says otherwise. When authority or required private data prevents that run, the result is `BLOCKED` or `NOT_RUN`, never complete. Once done, run an author self-check against the specification and the repository validation contract. Do not invoke a reviewer skill, publish a formal review, or approve your own work. ## Detect code smells mechanically Run the repository's declared linters and static analysers, including its dead-code, unused-variable, and complexity checks, before handback. For example, where the repository uses `ruff`, run `ruff check` with its configured rules over the source and test paths it declares; fix trivial findings and evaluate the rest. Use the output to inform your code-smell ledger. If a tool flags high complexity or an unused variable, either refactor the code to remove the smell or justify it in the ledger. Do not invent a tool the repository does not declare, and do not report a tool that was not run as passing. Apply the code-smell contract to every changed production and test path. Record each candidate as `NOT_PRESENT`, `SUSPECTED`, `CONFIRMED`, or `EXEMPT`, with exact evidence and impact. Under a no-code-smells policy, do not hand back while a diff-introduced or materially worsened `CONFIRMED` smell remains. Passing tests do not waive dead code, test theatre, exception-as-fallback, circular evidence, weak assertions, undefined heuristics, or another confirmed smell. A suspected smell requires inspection, not speculative refactoring; an exemption requires a cited repository rule or task requirement. Build a requirement ledger before handback. For every obligation record the changed production path, final observable, test node, input provenance, independent oracle, exact-head command, and observed result. A deviation, missing production-path test, unexecuted command, synthetic-only evidence where real-source evidence is required, or non-independent oracle leaves the requirement unmet. Do not relabel it as a limitation while claiming completion. Attach the smell ledger to this self-check when any smell candidate was found. ## Clean-head pre-flight Immediately before publication: 1. `git status --porcelain=v1 --untracked-files=all`: every required source, fixture, oracle, and generated input must be intentionally tracked, and no unexplained local file may contribute to a passing test. 2. `git diff --check` against the review base. 3. Repository-declared formatting, lint, type, static-analysis, schema, and artifact checks. 4. For Python, `python -m compileall` when appropriate as a syntax baseline; do not misrepresent it as undefined-name analysis. 5. Focused production-path tests followed by the complete mandated suite. 6. Repeat the final-output acceptance assertion from the clean committed head. Any failure returns the task to implementation. Do not publish a handback and promise that CI or the reviewer will discover the remaining defects. Commit and publish the authorised branch (never a protected branch, never with force), then stop for independent review by another identity using `code-review`, `hard-review`, or `devils-advocate-review`. Do not merge.