SuperCharged-Claude-Code-Upgrade/skills/plugins/claude-code-safety-net/CLAUDE.md

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

A Claude Code and OpenCode plugin that blocks destructive git and filesystem commands before execution. It works as a PreToolUse hook that intercepts Bash commands and denies dangerous operations like git reset --hard, rm -rf, and git checkout -- <files>.

Commands

• Setup: bun install
• All checks: bun run check (runs lint, typecheck, knip, ast-grep scan, tests)
• Single test: bun test tests/file.test.ts
• Lint: bun run lint (uses Biome)
• Type check: bun run typecheck
• Dead code: bun run knip
• AST scan: bun run sg:scan
• Build: bun run build

Architecture

The hook receives JSON input on stdin containing tool_name and tool_input. For Bash tools, it analyzes the command and outputs JSON with permissionDecision: "deny" to block dangerous operations.

Entry points:

• src/bin/cc-safety-net.ts — Claude Code CLI (reads stdin JSON)
• src/index.ts — OpenCode plugin export

Core analysis flow:

1. cc-safety-net.ts:main() parses JSON input, extracts command
2. analyze.ts:analyzeCommand() splits command on shell operators (;, &&, |, etc.)
3. analyzeSegment() tokenizes each segment, strips wrappers (sudo, env), identifies the command
4. Dispatches to rules-git.ts:analyzeGit() or rules-rm.ts:analyzeRm() based on command
5. Checks custom rules via rules-custom.ts:checkCustomRules() if configured

Key modules (src/core/):

• shell.ts: Shell parsing (splitShellCommands, shlexSplit, stripWrappers, shortOpts)
• rules-git.ts: Git subcommand analysis (checkout, restore, reset, clean, push, branch, stash)
• rules-rm.ts: rm analysis (allows rm -rf within cwd except when cwd is $HOME; temp paths always allowed; strict mode blocks non-temp)
• config.ts: Config loading, validation, merging (user ~/.cc-safety-net/config.json + project .safety-net.json)
• rules-custom.ts: Custom rule matching (checkCustomRules())
• audit.ts: Audit logging for blocked commands
• verify-config.ts: Config validator

Test utilities (tests/helpers.ts):

• assertBlocked(), assertAllowed() helpers for testing command analysis

Advanced detection:

• Recursively analyzes shell wrappers (bash -c '...') up to 5 levels deep
• Detects destructive commands in interpreter one-liners (python -c, node -e, ruby -e, perl -e)
• Handles xargs and parallel with template expansion and dynamic input detection
• Detects find -delete and find -exec rm patterns
• Redacts secrets (tokens, passwords, API keys) in block messages and audit logs
• Audit logging: blocked commands logged to ~/.cc-safety-net/logs/<session_id>.jsonl

Code Style (TypeScript)

• Use Bun instead of Node.js for running, testing, and building
• Biome for linting and formatting
• All functions require type annotations
• Use type | null syntax (not undefined where possible)
• Use kebab-case for file names (rules-git.ts, not rulesGit.ts)

Commit Conventions

When committing changes to files in commands/, hooks/, or .opencode/, use only fix or feat commit types. These directories contain user-facing skill definitions and hook configurations that represent features or fixes to the plugin's capabilities.

Environment Variables

• SAFETY_NET_STRICT=1: Strict mode (fail-closed on unparseable hook input/commands)
• SAFETY_NET_PARANOID=1: Paranoid mode (enables all paranoid checks)
• SAFETY_NET_PARANOID_RM=1: Paranoid rm (blocks non-temp rm -rf even within cwd)
• SAFETY_NET_PARANOID_INTERPRETERS=1: Paranoid interpreters (blocks interpreter one-liners)

Custom Rules

Users can define additional blocking rules in two scopes (merged, project overrides user):

• User scope: ~/.cc-safety-net/config.json (applies to all projects)
• Project scope: .safety-net.json (in project root)

Rules are additive only—cannot bypass built-in protections. Invalid config silently falls back to built-in rules only.

Testing

Use AGENT=1 bun test to run tests.

Bun Best Practices

• Use bun <file> instead of node <file> or ts-node <file>
• Use bun test instead of jest or vitest
• Use bun build instead of webpack or esbuild
• Use bun install instead of npm install
• Use bun run <script> instead of npm run <script>
• Bun automatically loads .env, so don't use dotenv

For more information, read the Bun API docs in node_modules/bun-types/docs/**.mdx.