kz-tob 43d7af8064 gh-cli: intercept GitHub fetches from MCP fetch tools (#274)
* gh-cli: intercept GitHub fetches from MCP fetch tools

The fetch hook only matched WebFetch, so a GitHub URL fetched through an
MCP fetch tool bypassed it entirely. Match `mcp__.*[Ff]etch` as well, which
covers Exa's `web_fetch_exa` and equivalents from other MCP servers.

A matcher alone is not enough: WebFetch passes a single `url`, while MCP
fetch tools pass a `urls` array and batch several pages into one call. Read
both shapes. A tool call is atomic, so one GitHub URL anywhere in a batch
denies the whole call, and each offending URL is labeled with its own
suggestion. Single-URL calls keep the message they had.

Split the URL classification into suggest_api, suggest_raw, and
suggest_github_com behind a suggest_for_url dispatcher so it can run per URL
in a loop, and collapse eight verbatim copies of the clone hint into one
helper. Behavior is unchanged; blob and tree merge into one branch because
they emitted identical text.

The plugin README's interception table now also lists the pull, issues,
releases, and gist patterns the hook already handled but never documented.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

* gh-cli: address review on the MCP fetch interceptor

Test the matcher. Nothing exercised the regex that decides whether the
hook runs at all, so a matcher firing on nothing would still pass every
other suite here. matcher.bats reads it out of hooks.json and checks it
against real tool names, and refuses to run against an empty matcher,
which would make every match assertion pass vacuously.

Widen the matcher to fetch, scrape, crawl, and extract. Firecrawl's
scrape and Tavily's extract retrieve a URL like any fetch tool but carry
no "fetch" in the name, so they bypassed the hook while the README
promised "any MCP fetch tool". The README now names what matches.

Check a string-valued `urls`. A server declaring `urls: string | string[]`
sent a bare string, `arrays` dropped it, and the fetch went out
unauthenticated. Listing the field twice keeps it under both shapes.
`prompt` is still not scanned, so a prompt mentioning a GitHub URL does
not false-deny.

Give the closing note its own line when several URLs are denied; it
previously trailed only the last entry.

Guard assert_suggestion_starts_with against an empty reason and an empty
prefix, either of which let it pass while inspecting nothing.

Document the api.github.com contents, releases, and actions rows. The
generic `gh api` row was actively wrong for /contents/, pointing readers
at the anti-pattern the shim exists to block.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-25 10:38:13 -04:00

Trail of Bits Skills Marketplace

A Claude Code plugin marketplace from Trail of Bits providing skills to enhance AI-assisted security analysis, testing, and development workflows. Codex can load this marketplace through its Claude marketplace compatibility.

Also see: claude-code-config · codex-config · skills-curated · claude-code-devcontainer · dropkit · coop

Installation

Claude Code Marketplace

/plugin marketplace add trailofbits/skills

Browse and Install Plugins

/plugin menu

Codex

Codex supports Claude plugin marketplaces directly, so this repository does not need Codex-specific sidecar metadata.

Install the marketplace with:

codex plugin marketplace add trailofbits/skills
codex plugin list
codex plugin add <plugin-name>@trailofbits

Local Development

To add the marketplace locally (e.g., for testing or development), navigate to the parent directory of this repository:

cd /path/to/parent  # e.g., if repo is at ~/projects/skills, be in ~/projects
/plugins marketplace add ./skills

Available Plugins

Smart Contract Security

Plugin Description
building-secure-contracts Smart contract security toolkit with vulnerability scanners for 6 blockchains
entry-point-analyzer Identify state-changing entry points in smart contracts for security auditing

Code Auditing

Plugin Description
agentic-actions-auditor Audit GitHub Actions workflows for AI agent security vulnerabilities
audit-context-building Understand a codebase before looking for bugs in it, one function at a time
burpsuite-project-parser Search and extract data from Burp Suite project files
c-review Comprehensive C/C++ security code review, with coverage verified against a parse of the source
differential-review Security-focused differential review of code changes with git history analysis
dimensional-analysis Annotate codebases with dimensional analysis comments to detect unit mismatches and formula bugs
fp-check Systematic false positive verification for security bug analysis with mandatory gate reviews
insecure-defaults Parallel audit workflow for fail-open insecure defaults, with a refuting verifier per candidate file
rust-review Comprehensive Rust security review covering safe/unsafe boundary, memory safety, concurrency, panic-DoS, FFI, and async runtime with SARIF output
semgrep-rule-creator Create and refine Semgrep rules for custom vulnerability detection
semgrep-rule-variant-creator Port existing Semgrep rules to new target languages with test-driven validation
sharp-edges Identify error-prone APIs, dangerous configurations, and footgun designs
static-analysis Static analysis toolkit with CodeQL, Semgrep, and SARIF parsing
supply-chain-risk-auditor Audit npm, PyPI, and Go dependencies for version-matched advisories, abandoned upstreams, publisher concentration, and install scripts
testing-handbook-skills Skills from the Testing Handbook: fuzzers, static analysis, sanitizers, coverage
trailmark Code graph analysis, bounded subagent context slicing, Mermaid diagrams, mutation testing triage, and protocol verification
variant-analysis Find similar vulnerabilities across codebases using pattern-based analysis
vulnerability-triage-brocards Triage vulnerability reports using 7 brocards to accept, dismiss, or request more info before deeper analysis

Malware Analysis

Plugin Description
yara-authoring YARA detection rule authoring with linting, atom analysis, and best practices

Verification

Plugin Description
constant-time-analysis Detect compiler-induced timing side-channels in cryptographic code
mutation-testing Configure mewt/muton mutation testing campaigns — scope targets, tune timeouts, optimize long runs
property-based-testing Write, review, and triage property-based tests — Hypothesis, fast-check, proptest, and Echidna or Medusa for Solidity invariants
spec-to-code-compliance Check code against the documentation that specifies it, across contracts, C/C++, services, and firmware
writing-lean-proofs Write structured Lean 4 proofs and design Lean libraries following Mathlib conventions
zeroize-audit Detect missing or compiler-eliminated zeroization of secrets in C/C++ and Rust

Reverse Engineering

Plugin Description
dwarf-expert Analyze DWARF debug info: parse and search DIEs, verify integrity, write DWARF parsing code

Mobile Security

Plugin Description
firebase-apk-scanner Scan Android APKs for Firebase security misconfigurations

Development

Plugin Description
code-improver Autonomous review-and-fix workflow over skills, plugins, or a branch, with a pluggable reviewer, findings ledger, escalation, and scope guard
devcontainer-setup Create pre-configured devcontainers with Claude Code and language-specific tooling
gh-cli Intercept GitHub URL fetches — WebFetch, MCP fetch tools, and curl/wget — and redirect to the authenticated gh CLI
git-cleanup Safely clean up git worktrees and local branches: a dynamic workflow gathers merge evidence and tries to refute its own delete recommendations, behind gated confirmation
goal-prompt Draft /goal commands for goal mode in Claude Code and Codex — verifiable completion conditions formatted to a copy-ready single line
github-triage Triage open GitHub issues and PRs: merge ready bot/approved PRs, review unreviewed ones via subagents, close resolved issues with cited comments, cross-link pending fixes, and score the rest with local-only priority and change-size estimates
let-fate-decide Draw Tarot cards using cryptographic randomness to add entropy to vague planning
modern-cpp Modern C++ best practices (C++20/23/26) with compiler hardening and safe idioms
modern-python Modern Python tooling and best practices with uv, ruff, and pytest
open-sourcing Prepare a repository for public release: secrets hygiene, licensing, CI readiness, and release automation
second-opinion Run code reviews using external LLM CLIs (OpenAI Codex, Google Gemini) on changes, diffs, or commits. Bundles Codex's built-in MCP server.

Team Management

Plugin Description
culture-index Interpret Culture Index survey results for individuals and teams

Tooling

Plugin Description
claude-in-chrome-troubleshooting Diagnose and fix Claude in Chrome MCP extension connectivity issues

Trophy Case

Bugs discovered using Trail of Bits Skills. Found something? Let us know!

When reporting bugs you've found, feel free to mention:

Found using Trail of Bits Skills

Skill Bug
constant-time-analysis Timing side-channel in ML-DSA signing

Contributing

We welcome contributions! See AGENTS.md for skill authoring guidelines, and run make check before you push — it runs most of CI locally (see AGENTS.md for what it does not cover).

License

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. Made by Trail of Bits.

S
Description
semgrep: Runs a Semgrep security scan over a codebase: detects languages, selects rulesets, presents the plan for explicit approval, then runs every approved ruleset…; modern-python: Configures Python projects with modern tooling (uv, ruff, ty). Use when creating projects, writing standalone scripts, or migrating from pip/Poetry/mypy/black.; codeql: Scans a codebase for security vulnerabilities using CodeQL's interprocedural data flow and taint tracking analysis. Triggers on "run codeql", "code…
Readme CC-BY-SA-4.0 14 MiB
Languages
Python 64.6%
JavaScript 18.8%
Shell 12.6%
YARA 0.6%
C 0.5%
Other 2.6%