Find out why a Claude Code permission rule isn't working, before you lose an afternoon to it.
Find out why a Claude Code permission rule isn't working, before you burn an afternoon on it. cc_lint.py reads your settings.json, settings.local.json or managed-settings.json and flags the mistakes Claude Code silently accepts: rules that never match, rules that are skipped at load time, allow rules a deny rule always beats, typos in keys and modes, and paths anchored in the wrong place.
Offline. Python 3.9+, no dependencies, no account, no network.
python3 tools/cc_lint.py examples/broken-settings.json # see every check fire
python3 tools/cc_lint.py .claude/settings.json # your project file
python3 tools/cc_lint.py --project . # user + project + local (+ managed) togetherExit code 0 = no errors, 1 = errors (add --strict to fail on warnings), so it drops into CI (examples/github-workflow.yml). --json gives machine-readable output, --quiet hides tips.
| Check | Example it catches |
|---|---|
| Invalid JSON, with a hint for comments/trailing commas | ["Bash(ls *)",] |
| Unknown top-level, permissions and sandbox keys, with "did you mean" | "modle", "allowedTools", "enable" |
| Invalid defaultMode | "acceptEdit" (valid: default/manual, acceptEdits, plan, auto, dontAsk, bypassPermissions) |
| Rules that are accepted but never match | Write(docs/**), Grep(src/**) (file checks use Edit(...) / Read(...)) |
| Rules Claude Code skips or ignores | mcp__github(create_issue), Bash(command:rm *), unanchored allow globs like mcp__* |
| Misplaced :* | Bash(git:* push) (the colon is literal mid-pattern) |
| Over-broad allow rules | Bash, Bash(git *), Bash(* --version), URL-constrained curl rules |
| Allow rules a deny/ask rule always beats | allow Bash(aws s3 ls) + deny Bash(aws *) |
| Path anchors | Read(/Users/alice/.ssh/**) (single / = settings root; use //), /path in user settings resolves under ~/.claude/ |
| WebFetch syntax | WebFetch(https://x.com/a) -> WebFetch(domain:x.com) |
| Risky modes in repository settings | "defaultMode": "bypassPermissions" in .claude/settings.json |
| Cross-scope conflicts (--project) | allowed in settings.local.json but denied in settings.json (deny wins) |
| Missing secret protection (tip) | no Read(.env) / Read(~/.ssh/**) deny rule |
Rules are checked against the Claude Code permissions and settings reference (code.claude.com/docs, November 2026). The key list in tools/cc_keys.json comes from the settings reference; update it if a newer Claude Code adds keys.
Zip, 19 KB, v1.0, 12 files. Free to use, modify and share for any purpose, including commercial work, as long as this notice stays in copies. Not affiliated with Anthropic.
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