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 wan-huiyan/agent-traffic-control --skill prove-test-failures-pre-existing-via-clean-worktreegit clone --depth 1 https://github.com/wan-huiyan/agent-traffic-controlWrote 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/wan-huiyan/agent-traffic-control/prove-test-failures-pre-existing-via-clean-worktree)<a href="https://agentmods.dev/skills/wan-huiyan/agent-traffic-control/prove-test-failures-pre-existing-via-clean-worktree"><img src="https://agentmods.dev/badge/skills/wan-huiyan/agent-traffic-control/prove-test-failures-pre-existing-via-clean-worktree/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/wan-huiyan/agent-traffic-control/prove-test-failures-pre-existing-via-clean-worktree"><img src="https://agentmods.dev/badge/skills/wan-huiyan/agent-traffic-control/prove-test-failures-pre-existing-via-clean-worktree.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 | $0.00192 | $0.01407 |
| Opus 5.5 | $0.00077 | $0.00563 |
| Sonnet 5.5 | $0.00038 | $0.00281 |
| Haiku 4.5 | $0.00019 | $0.00141 |
Grade A, and why
prove-test-failures-pre-existing-via-clean-worktree 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 — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prove test failures are pre-existing against a clean main worktree — don't guess "mine or theirs"
Problem
You finish a change, run the test suite (or a broad blast-radius set), and it reports failures. Two failure modes follow, both costly:
- False attribution → wasted debugging. You assume your change broke them and burn time investigating failures your diff never caused.
- Unproven dismissal → shipped regression. You wave them off as "probably pre-existing" with no evidence, and a real regression you DID introduce slips through under that cover.
The honest move is neither — it's a 30-second proof.
Context / Trigger conditions
- A post-change test run shows failures, particularly in modules/areas your diff did NOT touch.
- You're about to write "these are pre-existing, unrelated to my change" in a PR/handoff — but haven't proven it.
- You're in a git worktree where
mainis checked out in another worktree (sogit checkout mainfails withfatal: 'main' is already used by worktree at ...), and/or you have uncommitted changes, so the usual "switch to main and run" is awkward.
Solution
- Spin a throwaway clean checkout of the baseline (merge base /
origin/main):
A worktree beatsgit fetch origin --quiet git worktree add /tmp/clean origin/main # isolated; zero-touch to your working treegit stash: it doesn't disturb your edits, survives untracked files + new test assertions, and works when your own cwd is a worktree that can't switch to main. - Run the EXACT failing tests there (the specific node ids, not the whole suite):
( cd /tmp/clean/<test-root> && <runner> <exact::failing::test::ids> ) - Compare:
- Identical failures → pre-existing. Ship your change; note "N failures pre-existing on origin/main, not introduced here" in the PR/handoff (with the proof).
- Different / fewer failures → your change caused the delta. Now debug — you know exactly which.
- Clean up:
git worktree remove /tmp/clean --force.
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 Changed · +6 lines 77af27b3fc31
- 1mo ago First seen · 85 lines · 192 tokens per session scan A a78533761446
prove-test-failures-pre-existing-via-clean-worktree is a skill published in the GitHub repository wan-huiyan/agent-traffic-control (3 stars, last pushed 1mo ago), licensed MIT. It adds 192 tokens to every session and 1,407 once invoked, about $0.0008 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.
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