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 jsuvic/agent-profile --skill tdd-changegit clone --depth 1 https://github.com/jsuvic/agent-profileWrote 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/jsuvic/agent-profile/tdd-change)<a href="https://agentmods.dev/skills/jsuvic/agent-profile/tdd-change"><img src="https://agentmods.dev/badge/skills/jsuvic/agent-profile/tdd-change.svg" alt="Measured on agentmods" 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 | $0.00028 | $0.00538 |
| Opus 5 | $0.00014 | $0.00269 |
| Sonnet 5 | $0.00006 | $0.00108 |
| Haiku 4.5 | $0.00003 | $0.00054 |
Grade A, and why
tdd-change 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 7d 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 — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TDD Change
Instructions
- Identify the smallest observable behavior covered by the approved spec.
- Add or update one focused failing test or golden fixture before changing behavior code.
- Run the narrowest relevant test command and confirm RED: the test fails for the expected reason, not because of a typo, setup error, or unrelated failure.
- Implement the smallest change that satisfies the failing test and the spec.
- Run the same focused test command and confirm GREEN: the test passes without new warnings or unrelated failures.
- Refactor only after GREEN, then rerun the focused test command.
- Do not update golden files only to hide an unexplained behavior change.
Testing Anti-Patterns
- Do not write a tautological test: expected values must come from an independent source, never recomputed the way the code under test computes them.
- Do not assert on mock elements or mock call counts when a real behavior assertion is possible.
- Do not add production methods, flags, or exports that exist only for tests.
- Do not mock a dependency until you understand the side effects the test needs.
- Keep test doubles structurally complete enough to match the real data shape consumed by the code.
- If mock setup is larger than the behavior under test, consider a narrower integration test or a simpler production boundary.
Mock Boundary
- Mock only unmanaged external dependencies, such as network, clock, or filesystem you do not own.
- Prefer a fake over a stub, and a stub over a mock or spy.
- Use a spy only where outbound communication is itself the tested contract.
- Never introduce an abstraction that exists only for a test.
Seam Discipline
- Read
CONTEXT.mdwhen it exists; test names and interface names must match its glossary terms. - Test only at the seam declared in the issue brief; do not re-decide the seam inside the loop.
- If implementation shows the declared seam is wrong, stop and report
BLOCKEDwith the reason. Never silently move or redesign the seam.
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.
- 7d ago First seen · 51 lines · 28 tokens per session scan A 871dce548371
tdd-change is a skill published in the GitHub repository jsuvic/agent-profile (3 stars, last pushed 4d ago), licensed Apache-2.0. It adds 28 tokens to every session and 538 once invoked, about $0.0001 per session on Opus 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.
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