Borrowing it
Nothing to install: this file belongs to loerei/chronicle-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/loerei/chronicle-mcp/main/.agents/skills/skill-tdd/SKILL.mdgit clone --depth 1 https://github.com/loerei/chronicle-mcpWrote 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/loerei/chronicle-mcp/skill-tdd)<a href="https://agentmods.dev/skills/loerei/chronicle-mcp/skill-tdd"><img src="https://agentmods.dev/badge/skills/loerei/chronicle-mcp/skill-tdd/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/loerei/chronicle-mcp/skill-tdd"><img src="https://agentmods.dev/badge/skills/loerei/chronicle-mcp/skill-tdd.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 | $0.00017 | $0.02565 |
| Opus 5.5 | $0.00007 | $0.01026 |
| Sonnet 5.5 | $0.00003 | $0.00513 |
| Haiku 4.5 | $0.00002 | $0.00257 |
Grade A, and why
skill-tdd 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.
How it starts
The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill TDD
Test and benchmark skills (SKILL.md), subdocs, and policies (AGENTS.md) using red-green-regression cycles, 4-axis coverage, single-call parallel dispatch, and hypothesis ledgers.
Directives
- Red Baseline First: MUST run a baseline subagent without the skill on negative fixtures to verify failure (Red) before testing candidate versions.
- Double-Sided Fixtures: MUST test both a Negative Fixture (agent must block/refactor) and a Positive Fixture (agent must clear/approve) to prevent false-positive hyper-critique.
- 4-Axis Coverage: Test suites MUST cover Directives, Decision Branches, Anti-Patterns, and Domain Diversity (minimum 2–3 distinct domains) per REFERENCE.md.
- Test Matrix Budget:
- Fast Dev Loop: $N_{\text{tests}} \ge 2$, $N_{\text{runs}} \in [1, 3]$ per test.
- Graduation Gate: $N_{\text{tests}} \ge 3\text{--}4$ diverse domain fixtures, $N_{\text{runs}} \ge 5\text{--}10$ with fresh 0-prior-context subagents.
- Graduation Criteria: $\Delta_{\text{Suite}} \ge +60%$, 100% positive clearance, and 0 cheat flags.
- Single-Call Parallel Matrix Dispatch: MUST launch all independent test trials (baseline and treated runs across all fixtures) in a single concurrent batch via
invoke_subagent(Subagents=[...]). NEVER dispatch trials sequentially across multiple turns. Tag each subagent clearly:Role: "[Baseline/Treated] | <Fixture> | Run <K>". - Spec Decoupling & Anti-Snooping Audit:
TEST_SPEC.mdandHYPOTHESIS.mdMUST reside in.scratch/<skill>-versions/specs/and NEVER inside fixture code directories (.scratch/fixtures/<name>/).- Evaluators MUST inspect subagent tool calls in transcripts. If a baseline subagent reads repository
SKILL.mdfiles or ANY subagent readsTEST_SPEC.md/HYPOTHESIS.md, abort immediately with:
Overfitting cheat detected: Subagent snooped <path>.
- Immutable Prompt Contract: MUST copy prompts verbatim from
TEST_SPEC.md. NEVER inject hints, line numbers, or leading context. - Zero Prior Context: Spawn every test run using a fresh subagent with 0 prior context. NEVER reuse subagent conversation threads.
- Sandbox Delta Versioning:
- NEVER edit production skills/policies directly on test failure.
- Create a sandbox (
.scratch/<skill>-versions/) with candidate files (SKILL.v1.md) and an append-onlyHYPOTHESIS.md(NEVER delete entries). - Point test subagents to candidate versions. Graduate to production only after meeting the $\Delta_{\text{Suite}}$ threshold.
- Anti-Overfitting Cheats:
SKILL.mdandREFERENCE.mdMUST express domain-agnostic rules. NEVER hardcode test fixture entities, class names, or mock values.- Evaluators detecting leaked words or prompt hints MUST abort immediately with:
Overfitting cheat detected: <reason>.
- Zero-Delta Anomaly: If 100% of runs yield Double-GREEN ($\Delta = 0$), classify as a Zero-Delta Failure (harden test fixture or prune redundant skill rules).
- Seam-Only Assertions: Verify behavior at public seams (verdict, scorecard rows, tool call constraints, stop boundary). NEVER assert on private reasoning traces.
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.
- 1mo ago First seen · 125 lines · 17 tokens per session scan A d9fd4b70d856
skill-tdd is a skill published in the GitHub repository loerei/chronicle-mcp (0 stars, last pushed 1mo ago), licensed MIT. It adds 17 tokens to every session and 2,565 once invoked, about $0.0001 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
engram-testing-coverage
TDD and coverage standards for Engram. Trigger: When implementing behavior changes in any package.
conductor-implement
Execute tasks from a track's implementation plan following TDD workflow.
principle-test-behavior-not-implementation
Apply when you write, change, or keep a test. Assert what the code's users can observe, so that the test fails when that behavior breaks and keeps passing when only the internals change.
tdd
This skill should be used when the user wants to implement features or fix bugs using test-driven development. Enforces the RED-GREEN-REFACTOR cycle with vertical slicing, context isolation between test writing and implementation, human checkpoints, and auto-test feedback loops. Uses multi-agent orchestration with the…
iterative-development
TDD iteration loops using Claude Code Stop hooks - runs tests after each response, feeds failures back automatically.
mobiai-mobile-tdd
You MUST use this before writing any implementation code for a mobile feature, bug fix, refactor, or behavior change. Tests come before implementation — no exceptions.