Borrowing it
Nothing to install: this file belongs to mtarcure/claude-vibe-squad. 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/mtarcure/claude-vibe-squad/main/.agents/skills/diff-aware-semgrep-scan/SKILL.mdgit clone --depth 1 https://github.com/mtarcure/claude-vibe-squadWrote 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/mtarcure/claude-vibe-squad/diff-aware-semgrep-scan)<a href="https://agentmods.dev/skills/mtarcure/claude-vibe-squad/diff-aware-semgrep-scan"><img src="https://agentmods.dev/badge/skills/mtarcure/claude-vibe-squad/diff-aware-semgrep-scan/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/mtarcure/claude-vibe-squad/diff-aware-semgrep-scan"><img src="https://agentmods.dev/badge/skills/mtarcure/claude-vibe-squad/diff-aware-semgrep-scan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00064 | $0.00452 |
| Opus 5 | $0.00032 | $0.00226 |
| Sonnet 5 | $0.00013 | $0.00090 |
| Haiku 4.5 | $0.00006 | $0.00045 |
Grade A, and why
diff-aware-semgrep-scan 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 9d 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
Diff-Aware Semgrep Scan
Scan only what changed, with the rules that matter for the change, so static-analysis signal survives contact with a large legacy baseline.
Steps
- Fix the comparison range (
git diff --name-only <base>...HEAD) and collect changed files plus their language mix. - Select rule packs by language and by change shape — auth, deserialization, templating, SQL, subprocess, crypto — rather than running one generic pack over everything.
- Run
semgrep --config <packs> --baseline-commit <base>so pre-existing findings are suppressed and only newly-introduced ones surface. - Re-run without the baseline flag on the changed files alone when a finding's history matters; a pre-existing issue in a file the change now exposes to untrusted input is a new risk even though the line is old.
- Triage every hit against
findings-filter: reachability from an untrusted source, attacker-controlled input, and real consequence. - For each true positive, capture the rule id, the file:line, the data path from source to sink, and the minimal fix.
- For each false positive, record why the rule misfired; recurring misfires are input to
semgrep-rule-author, not something to silence per-finding. - Report scan coverage honestly: files skipped for parse errors or unsupported languages are gaps, not passes.
Acceptance
- The scan states its base commit and the rule packs selected, with a reason for the selection.
- Newly-introduced findings are separated from pre-existing ones.
- Every reported finding has a source-to-sink path, not just a rule match.
- False positives are explained, and repeat offenders are routed to rule authoring.
- Unscanned or unparsed files are listed as coverage gaps.
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.
- 9d ago First seen · 27 lines · 64 tokens per session scan A 9381fe200663
diff-aware-semgrep-scan is a skill published in the GitHub repository mtarcure/claude-vibe-squad (122 stars, last pushed today), licensed MIT. It adds 64 tokens to every session and 452 once invoked, about $0.0003 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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