Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add TAKEOFF69/codex-skills-kit --skill gate-engineeringgit clone --depth 1 https://github.com/TAKEOFF69/codex-skills-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/takeoff69/codex-skills-kit/gate-engineering)<a href="https://agentmods.dev/skills/takeoff69/codex-skills-kit/gate-engineering"><img src="https://agentmods.dev/badge/skills/takeoff69/codex-skills-kit/gate-engineering/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/takeoff69/codex-skills-kit/gate-engineering"><img src="https://agentmods.dev/badge/skills/takeoff69/codex-skills-kit/gate-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00080 | $0.00926 |
| Opus 5.5 | $0.00032 | $0.00370 |
| Sonnet 5.5 | $0.00016 | $0.00185 |
| Haiku 4.5 | $0.00008 | $0.00093 |
Grade A, and why
gate-engineering scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Gate Engineering
Build standing quality nets that prove they detect intended defect class.
Scope
This skill applies to persistent repository gates: lint rules, CI checks, tripwires, contract suites, corpus detectors, and golden tests. Ordinary unit tests written with a feature do not each need full gate ceremony.
Core rule
A gate never observed failing is unproven. Ship known-bad input, known-good twin, and repeatable way to prove catch.
Five laws
- Prove red, then green. Seed representative defect and observe non-zero failure. Fix it and observe pass. Preserve both fixtures and expose
--selftestor equivalent deterministic command. - Fix classes, not instances. Recurrence turns one reported case into corpus problem. Detect class, scan full owned corpus, fix all findings, then keep detector as gate.
- Keep fixtures hermetic. Commit inputs. Avoid live database, mutable cache, network, current date, or content SHA dependencies unless gate explicitly tests those boundaries.
- Assert contract, not incidental snapshot. Prefer invariant such as presence, range, mapping, ordering, or semantic label. Byte-exact and pixel-exact snapshots need clear reason and controlled update process.
- Audit consumers. Producer validation does not protect cached, read, import, or alternate write paths. Enumerate bypasses and gate contract where consumers can violate it.
Assertion traps
- Assert presence before uniqueness – zero matches are trivially unique.
- Assert selection is non-empty before
all(...)or universal validity. - Ensure failure fixture reaches code path under test rather than being filtered earlier.
- Include near-miss good fixture so detector does not encode broad false positives.
- Test disabled or feature-flagged path by toggling it in controlled run.
Gate lifecycle
- Recalibrate baseline after legitimate behavior change; do not weaken invariant to make CI green.
- Re-enable disabled gate only after current corpus passes it.
- Refresh tripwire baseline with producer or consumer refresh that changes expected truth.
- Match gate cadence to data cadence.
- Version fixture schema when parser or contract changes.
- Record scoped skip with owner and expiry; never silently disable.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 94 lines · 80 tokens per session scan A 5709917f1773
gate-engineering is a skill published in the GitHub repository TAKEOFF69/codex-skills-kit (8 stars, last pushed 3mo ago), licensed MIT. It adds 80 tokens to every session and 926 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other skills, from other repositories
pin-guardrail
Pin a shell guardrail (a hook, a git hook, a checker script) with a behavioral test suite, prove the suite is real by mutating the code, and wire it into CI with its mutation ledger. Use when asked to "add tests for this hook", "pin that guard", "mutation-test this script", "this hook has no test", "wire the suite…
deploy-and-runtime-verification
MANDATORY deploy after every code change. Typecheck → deploy → purge CDN → E2E on production → visual verify → fix-forward loop. Workers Builds native CI/CD, D1 Time Travel PIT recovery, D1→R2 long-term backups, wrangler rollback, wrangler secrets management, structured observability, cross-browser smoke tests…
vkm-verify
Prove a green check actually ran, covered the change, and can fail. Use before claiming done / tests pass / CI green / committed / deployed, when a guard or lint has never once fired, or when a pass contradicts a symptom the user still sees. NOT for writing tests or debugging a known-red failure.
php-quality-tooling
Use when setting up PHPStan, Rector, or PHP-CS-Fixer on a non-Laravel PHP project, incl. CI wiring. Do NOT use for Laravel (Pint/Larastan), tests, or syntax.
Verification & Quality Assurance
Comprehensive truth scoring, code quality verification, and automatic rollback system with 0.95 accuracy threshold for ensuring high-quality agent outputs and codebase reliability.
quality-scan
Run a scoped, read-only quality scan and report exact-candidate evidence, failures and frozen debt. Use for an ad-hoc gate sweep or release preparation; a static scan is not full release acceptance.