Claude Security puts a team of agents to work inside your Claude Code session: map the architecture, build a threat model, hunt across components, and independently verify every finding before it reaches the report. Optionally it turns confirmed findings into patch files that you review and apply. It is the in-session version of Anthropic's hosted Claude Security product.
What it does
Where Claude Security runs and what it adds, from its documentation
Scan codebase: whole repository or a scoped part at a chosen effort tier
Scan changes: a branch diff, a PR diff, or one commit
Suggest patches: turns a report's findings into F.patch files, never applied automatically
Writes CLAUDE-SECURITY-RESULTS.md, .jsonl and .sarif (SARIF 2.1.0) plus a revision stamp
Verifiers try to disprove each finding; false positives are discarded
When to use it
Good fit
Scanning your own repositories for vulnerabilities before release
Reviewing a feature branch or PR diff for security flaws
Producing SARIF for GitHub code scanning or IDE viewers
Not for
Untrusted third-party repositories, unless the whole session runs inside sandbox-runtime
Replacing SAST, dependency scanning or code review (README says it complements them)
How to install Claude Security
You need: Claude Code; Python 3.9 or newer on PATH; A git checkout for scanning changes and suggesting patches (whole-repo scan works without one); README recommends Claude Opus 5.5 or Fable 5.1
