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 lfyxhappy/lfcode --skill contract-test-engineergit clone --depth 1 https://github.com/lfyxhappy/lfcodeWrote 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/lfyxhappy/lfcode/contract-test-engineer)<a href="https://agentmods.dev/skills/lfyxhappy/lfcode/contract-test-engineer"><img src="https://agentmods.dev/badge/skills/lfyxhappy/lfcode/contract-test-engineer/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/lfyxhappy/lfcode/contract-test-engineer"><img src="https://agentmods.dev/badge/skills/lfyxhappy/lfcode/contract-test-engineer.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 | $0.00054 | $0.00353 |
| Opus 5.5 | $0.00022 | $0.00141 |
| Sonnet 5.5 | $0.00011 | $0.00071 |
| Haiku 4.5 | $0.00005 | $0.00035 |
Grade A, and why
contract-test-engineer 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 1mo 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.
What it actually says
Contract Test Engineer
Make cross-boundary expectations explicit and executable.
Workflow
- Read repository instructions, authoritative schemas or specifications, versioning policy, provider and consumer code, and existing compatibility tests.
- Identify the contract surface: endpoints or topics, request and response fields, defaults, nullability, errors, ordering, encoding, authorization, and version behavior.
- Choose the authoritative source of truth and record which fields are guaranteed, deprecated, optional, or implementation-specific.
- Create focused examples covering valid requests, invalid input, error payloads, omitted and unknown fields, backward compatibility, and forward-compatible parsing where the product supports it.
- Exercise the provider and consumer through their real serialization or transport boundary, using generated or local isolated artifacts when available.
- Verify the affected producer and consumer checks. Flag any required coordinated deployment, migration window, or remote validation instead of assuming it is safe.
Boundaries
- Keep contract assessment read-only unless the user asks to change tests, schemas, or implementation.
- Do not infer a compatibility promise from one implementation detail or a single happy-path sample.
- Do not publish schemas, mutate a shared registry, call production endpoints, or change compatibility versions without explicit authorization.
- Preserve unknown fields and error semantics when the documented compatibility policy requires them.
Completion Check
Report the contract source, producer and consumer coverage, compatibility assumptions, breaking-change findings, verification evidence, and remaining coordination work.
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.
- 1mo ago First seen · 29 lines · 54 tokens per session scan A 1d9271eaec76
contract-test-engineer is a skill published in the GitHub repository lfyxhappy/lfcode (2 stars, last pushed 1mo ago), licensed MIT. It adds 54 tokens to every session and 353 once invoked, about $0.0002 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 2026-09-05.
Other skills, from other repositories
Check work (verify against criteria)
Verify an implementation against acceptance criteria with a reviewer and a tester.
PR babysit (watch & drive to green)
Watch a pull request and delegate fixes until CI is green and reviews are addressed. Requires the GitHub MCP server or gh.
Write tests
Add focused, meaningful tests for code — happy path plus the edge cases that matter.
ai-evaluation-patterns
Guides expert-level ai evaluation patterns implementation: ai-ml and testing decision frameworks, production-ready patterns, and concrete templates for ai evaluation patterns workflows. Use when the user asks about ai evaluation patterns, ai evaluation patterns configuration, or ai-ml best practices for ai projects.…
backend-architect
Becomes a senior backend architect who designs scalable, resilient server-side systems with clear API contracts, sound data models, and documented trade-offs. Use when the user needs system design, database architecture, API contract definition, caching strategy, or backend technology selection. Do NOT use when…
performance-engineer
Becomes a senior performance engineer who identifies bottlenecks, designs optimization strategies, and conducts load testing using systematic profiling and benchmarking methodology. Use when the user needs performance analysis, load testing, bottleneck identification, latency optimization, or capacity planning. Do NOT…