Borrowing it
Nothing to install: this file belongs to mick-gsk/drift. 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/mick-gsk/drift/main/.github/skills/drift-ground-truth-fixture-development/SKILL.mdgit clone --depth 1 https://github.com/mick-gsk/driftWrote 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/mick-gsk/drift/drift-ground-truth-fixture-development)<a href="https://agentmods.dev/skills/mick-gsk/drift/drift-ground-truth-fixture-development"><img src="https://agentmods.dev/badge/skills/mick-gsk/drift/drift-ground-truth-fixture-development/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/mick-gsk/drift/drift-ground-truth-fixture-development"><img src="https://agentmods.dev/badge/skills/mick-gsk/drift/drift-ground-truth-fixture-development.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 | $0.00089 | $0.01477 |
| Opus 5 | $0.00044 | $0.00739 |
| Sonnet 5 | $0.00018 | $0.00295 |
| Haiku 4.5 | $0.00009 | $0.00148 |
Grade A, and why
drift-ground-truth-fixture-development 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 10d 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 — 168 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Drift Ground-Truth Fixture Development Skill
Use this skill when Drift needs reproducible fixture coverage for signal behavior.
When To Use
- A new signal needs baseline TP and TN coverage
- A false positive or false negative needs to become a regression fixture
- A threshold or calibration change needs boundary coverage
- A benign lookalike case needs a confounder fixture
- A signal depends on history-like data and needs
file_history_overrides
Core Rules
- Run the Drift Policy Gate first. Fixtures should validate admissible work, not justify inadmissible work.
- Keep fixtures minimal and deterministic. No external dependencies, no hidden runtime assumptions.
- Every fixture needs explicit expectations. Empty fixtures are invalid.
- Prefer source-like realism over size. Small but representative beats large and noisy.
- Use fixture kinds intentionally. TP/TN are the baseline; boundary and confounder cases are for calibration and trust hardening.
- Fixture und Logik zusammen bauen — nicht alle Fixtures zuerst. Eine TP-Fixture schreiben, die passende Signal-Logik implementieren, dann TN. Horizontales Batch-Schreiben produziert Tests gegen imaginiertes Verhalten.
- Nur an echten Systemgrenzen mocken. Externe APIs, Zeit und Dateisystem sind valide Mock-Ziele. Interne Signal-Methoden, AST-Helfer und Scoring-Zwischenwerte nicht — teste ausschließlich den Public-Output von
analyze(). Kurzregel: AST/Scoring = in-process, direkt testbar; Git-History =file_history_overridesals lokaler Stand-in; externe HTTP-Calls = an der Interface-Grenze mocken.
Step 0: Run The Drift Policy Gate
Before adding or changing fixtures, use the gate format from .github/instructions/drift-policy.instructions.md.
Step 1: Choose The Right Fixture Type
Use these types deliberately:
- positive the signal must fire
- negative the signal must not fire
- boundary the case sits near a threshold or decision edge
- confounder the case looks like a real finding but is intentionally benign
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.
- 10d ago First seen · 168 lines · 89 tokens per session scan A 1424ebd7b8c0
drift-ground-truth-fixture-development is a skill published in the GitHub repository mick-gsk/drift (15 stars, last pushed 1mo ago), licensed MIT. It adds 89 tokens to every session and 1,477 once invoked, about $0.0004 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 2026-08-30.
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