{"id":45679658,"url":"https://github.com/Dicklesworthstone/destructive_command_guard","last_synced_at":"2026-03-09T20:01:22.906Z","repository":{"id":331934423,"uuid":"1130004860","full_name":"Dicklesworthstone/destructive_command_guard","owner":"Dicklesworthstone","description":"The Destructive Command Guard (dcg) is for blocking dangerous git and shell commands from being executed by agents.","archived":false,"fork":false,"pushed_at":"2026-03-04T07:03:22.000Z","size":10880,"stargazers_count":611,"open_issues_count":0,"forks_count":35,"subscribers_count":2,"default_branch":"main","last_synced_at":"2026-03-04T13:29:27.043Z","etag":null,"topics":["ai-agents","cli","developer-tools","git","rust","safety"],"latest_commit_sha":null,"homepage":"","language":"Rust","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"other","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/Dicklesworthstone.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":"docs/security-model.md","support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null,"notice":null,"maintainers":null,"copyright":null,"agents":"AGENTS.md","dco":null,"cla":null}},"created_at":"2026-01-07T22:27:34.000Z","updated_at":"2026-03-04T12:03:13.000Z","dependencies_parsed_at":null,"dependency_job_id":null,"html_url":"https://github.com/Dicklesworthstone/destructive_command_guard","commit_stats":null,"previous_names":["dicklesworthstone/destructive_command_guard"],"tags_count":20,"template":false,"template_full_name":null,"purl":"pkg:github/Dicklesworthstone/destructive_command_guard","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Dicklesworthstone%2Fdestructive_command_guard","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Dicklesworthstone%2Fdestructive_command_guard/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Dicklesworthstone%2Fdestructive_command_guard/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Dicklesworthstone%2Fdestructive_command_guard/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/Dicklesworthstone","download_url":"https://codeload.github.com/Dicklesworthstone/destructive_command_guard/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/Dicklesworthstone%2Fdestructive_command_guard/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":30309998,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-03-09T17:35:44.120Z","status":"ssl_error","status_checked_at":"2026-03-09T17:35:43.707Z","response_time":61,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.5:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["ai-agents","cli","developer-tools","git","rust","safety"],"created_at":"2026-02-24T14:00:36.932Z","updated_at":"2026-03-09T20:01:22.632Z","avatar_url":"https://github.com/Dicklesworthstone.png","language":"Rust","readme":"# dcg (Destructive Command Guard)\n\n\u003cdiv align=\"center\"\u003e\n  \u003cimg src=\"illustration.webp\" alt=\"Destructive Command Guard - Protecting your code from accidental destruction\"\u003e\n\u003c/div\u003e\n\n\u003cdiv align=\"center\"\u003e\n\n[![CI](https://github.com/Dicklesworthstone/destructive_command_guard/actions/workflows/ci.yml/badge.svg)](https://github.com/Dicklesworthstone/destructive_command_guard/actions/workflows/ci.yml)\n[![Coverage](https://img.shields.io/codecov/c/github/Dicklesworthstone/destructive_command_guard?label=coverage)](https://codecov.io/gh/Dicklesworthstone/destructive_command_guard)\n[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)\n\n\u003c/div\u003e\n\nA high-performance hook for AI coding agents that blocks destructive commands before they execute, protecting your work from accidental deletion.\n\n**Supported:** [Claude Code](https://claude.ai/code), [Gemini CLI](https://github.com/google-gemini/gemini-cli), [GitHub Copilot CLI](https://docs.github.com/en/copilot/concepts/agents/coding-agent/about-hooks), [OpenCode](https://opencode.ai) (via [community plugin](https://github.com/jms830/opencode-dcg-plugin)), [Aider](https://aider.chat/) (limited—git hooks only), [Continue](https://continue.dev) (detection only), [Codex CLI](https://github.com/openai/codex) (detection only)\n\n\u003cdiv align=\"center\"\u003e\n\u003ch3\u003eQuick Install\u003c/h3\u003e\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | bash -s -- --easy-mode\n```\n\n\u003cp\u003e\u003cem\u003eWorks on Linux, macOS, and Windows (WSL). Auto-detects your platform and downloads the right binary.\u003c/em\u003e\u003c/p\u003e\n\u003c/div\u003e\n\n---\n\n## TL;DR\n\n**The Problem**: AI coding agents (Claude, GPT, etc.) occasionally run catastrophic commands like `git reset --hard`, `rm -rf ./src`, or `DROP TABLE users`—destroying hours of uncommitted work in seconds.\n\n**The Solution**: dcg is a high-performance hook that intercepts destructive commands *before* they execute, blocking them with clear explanations and safer alternatives.\n\n### Why Use dcg?\n\n| Feature | What It Does |\n|---------|--------------|\n| **Zero-Config Protection** | Blocks dangerous git/filesystem commands out of the box |\n| **49+ Security Packs** | Databases, Kubernetes, Docker, AWS/GCP/Azure, Terraform, and more |\n| **Sub-Millisecond Latency** | SIMD-accelerated filtering—you won't notice it's there |\n| **Heredoc/Inline Script Scanning** | Catches `python -c \"os.remove(...)\"` and embedded shell scripts |\n| **Smart Context Detection** | Won't block `grep \"rm -rf\"` (data) but will block `rm -rf /` (execution) |\n| **Scan Mode for CI** | Pre-commit hooks and CI integration to catch dangerous commands in code review |\n| **Fail-Open Design** | Never blocks your workflow due to timeouts or parse errors |\n| **Explain Mode** | `dcg explain \"command\"` shows exactly why something is blocked |\n\n### Quick Example\n\n```bash\n# AI agent tries to run:\n$ git reset --hard HEAD~5\n\n# dcg intercepts and blocks:\n════════════════════════════════════════════════════════════════\nBLOCKED  dcg\n────────────────────────────────────────────────────────────────\nReason:  git reset --hard destroys uncommitted changes\n\nCommand: git reset --hard HEAD~5\n\nTip: Consider using 'git stash' first to save your changes.\n════════════════════════════════════════════════════════════════\n```\n\n### Enable More Protection\n\n```toml\n# ~/.config/dcg/config.toml\n[packs]\nenabled = [\n    \"database.postgresql\",    # Blocks DROP TABLE, TRUNCATE\n    \"kubernetes.kubectl\",     # Blocks kubectl delete namespace\n    \"cloud.aws\",              # Blocks aws ec2 terminate-instances\n    \"containers.docker\",      # Blocks docker system prune\n]\n```\n\n### Agent-Specific Profiles\n\ndcg automatically detects which AI coding agent is invoking it and can apply\nagent-specific trust levels:\n\n```toml\n# Trust Claude Code more\n[agents.claude-code]\ntrust_level = \"high\"\nadditional_allowlist = [\"npm run build\"]\n\n# Restrict unknown agents\n[agents.unknown]\ntrust_level = \"low\"\nextra_packs = [\"paranoid\"]\n```\n\nSee [docs/agents.md](docs/agents.md) for full documentation on supported agents\nand configuration options.\n\n---\n\n## Origins \u0026 Authors\n\nThis project began as a Python script by Jeffrey Emanuel, who recognized that AI coding agents, while incredibly useful, occasionally run catastrophic commands that destroy hours of uncommitted work. The original implementation was a simple but effective hook that intercepted dangerous git and filesystem commands before execution.\n\n- **[Jeffrey Emanuel](https://github.com/Dicklesworthstone)** - Original concept and Python implementation ([source](https://github.com/Dicklesworthstone/misc_coding_agent_tips_and_scripts/blob/main/DESTRUCTIVE_GIT_COMMAND_CLAUDE_HOOKS_SETUP.md)); substantially expanded the Rust version with the modular pack system (49+ security packs), heredoc/inline-script scanning, the three-tier architecture, context classification, allowlists, scan mode, and the dual regex engine\n- **[Darin Gordon](https://github.com/Dowwie)** - Initial Rust port with performance optimizations\n\nThe initial Rust port by Darin maintained pattern compatibility with the original Python implementation while adding sub-millisecond execution through SIMD-accelerated filtering and lazy-compiled regex patterns. Jeffrey subsequently expanded the Rust codebase dramatically to add the features described above.\n\n## Why This Exists\n\nAI coding agents are powerful but fallible. They can accidentally run destructive commands that wipe out hours of uncommitted work, drop database tables, or delete critical files. Common scenarios include:\n\n- **\"Let me clean up the build artifacts\"** → `rm -rf ./src` (typo)\n- **\"I'll reset to the last commit\"** → `git reset --hard` (destroys uncommitted changes)\n- **\"Let me fix the merge conflict\"** → `git checkout -- .` (discards all modifications)\n- **\"I'll clean up untracked files\"** → `git clean -fd` (permanently deletes untracked files)\n\nThis hook intercepts dangerous commands *before* execution and blocks them with a clear explanation, giving you a chance to stash your changes first, or to consciously proceed by running the command manually.\n\n## What It Blocks\n\n**Git commands that destroy uncommitted work:**\n- `git reset --hard` / `git reset --merge` - destroys uncommitted changes\n- `git checkout -- \u003cfile\u003e` - discards file modifications\n- `git restore \u003cfile\u003e` (without `--staged`) - discards uncommitted changes\n- `git clean -f` - permanently deletes untracked files\n\n**Git commands that can destroy remote history:**\n- `git push --force` / `git push -f` - overwrites remote commits\n- `git branch -D` - force-deletes branches without merge check\n\n**Git commands that destroy stashed work:**\n- `git stash drop` / `git stash clear` - permanently deletes stashes\n\n**Filesystem commands:**\n- `rm -rf` on any path outside `/tmp`, `/var/tmp`, or `$TMPDIR`\n\n**Heredoc and inline-script scanning (AST-based):**\n- Blocks destructive operations embedded inside heredocs, here-strings, and inline scripts\n  (e.g., `python -c`, `bash -c`, `node -e`)\n- Supported languages: bash, python, javascript, typescript, ruby, perl, go\n- Fail-open on parse errors/timeouts to avoid breaking workflows\n\n## What It Allows\n\n**Safe git operations pass through silently:**\n- `git status`, `git log`, `git diff`, `git add`, `git commit`, `git push`, `git pull`, `git fetch`\n- `git branch -d` (safe delete with merge check)\n- `git stash`, `git stash pop`, `git stash list`\n\n**Explicitly safe patterns:**\n- `git checkout -b \u003cbranch\u003e` - creating new branches\n- `git checkout --orphan \u003cbranch\u003e` - creating orphan branches\n- `git restore --staged \u003cfile\u003e` - unstaging (safe, doesn't touch working tree)\n- `git clean -n` / `git clean --dry-run` - preview mode\n- `rm -rf /tmp/*`, `rm -rf /var/tmp/*`, `rm -rf $TMPDIR/*` - temp directory cleanup\n\n## Modular Pack System\n\ndcg uses a modular \"pack\" system to organize destructive command patterns by category. Packs can be enabled or disabled in the configuration file.\n\n- Full pack ID index: `docs/packs/README.md`\n- Canonical descriptions + pattern counts: `dcg packs --verbose`\n\n### Core Packs (enabled by default)\n- `core.filesystem` - Protects against dangerous rm -rf commands outside temp directories\n- `core.git` - Protects against destructive git commands that can lose uncommitted work, rewrite history, or destroy stashes\n\n**Common packs enabled by default:**\n- `database.postgresql` - Protects against destructive PostgreSQL operations\n- `containers.docker` - Protects against destructive Docker operations like system prune\n\n### Storage Packs\n- `storage.s3` - Protects against destructive S3 operations like bucket removal, recursive deletes, and sync --delete.\n- `storage.gcs` - Protects against destructive GCS operations like bucket removal, object deletion, and recursive deletes.\n- `storage.minio` - Protects against destructive MinIO Client (mc) operations like bucket removal, object deletion, and admin operations.\n- `storage.azure_blob` - Protects against destructive Azure Blob Storage operations like container deletion, blob deletion, and azcopy remove.\n\n### Remote Packs\n- `remote.rsync` - Protects against destructive rsync operations like --delete and its variants.\n- `remote.scp` - Protects against destructive SCP operations like overwrites to system paths.\n- `remote.ssh` - Protects against destructive SSH operations like remote command execution and key management.\n\n### Database Packs\n- `database.postgresql` - Protects against destructive PostgreSQL operations like DROP DATABASE, TRUNCATE, and dropdb.\n- `database.mysql` - MySQL/MariaDB guard.\n- `database.mongodb` - Protects against destructive MongoDB operations like dropDatabase, dropCollection, and remove without criteria.\n- `database.redis` - Protects against destructive Redis operations like FLUSHALL, FLUSHDB, and mass key deletion.\n- `database.sqlite` - Protects against destructive SQLite operations like DROP TABLE, DELETE without WHERE, and accidental data loss.\n\n### Container Packs\n- `containers.docker` - Protects against destructive Docker operations like system prune, volume prune, and force removal.\n- `containers.compose` - Protects against destructive Docker Compose operations like down -v which removes volumes.\n- `containers.podman` - Protects against destructive Podman operations like system prune, volume prune, and force removal.\n\n### Kubernetes Packs\n- `kubernetes.kubectl` - Protects against destructive kubectl operations like delete namespace, drain, and mass deletion.\n- `kubernetes.helm` - Protects against destructive Helm operations like uninstall and rollback without dry-run.\n- `kubernetes.kustomize` - Protects against destructive Kustomize operations when combined with kubectl delete or applied without review.\n\n### Cloud Provider Packs\n- `cloud.aws` - Protects against destructive AWS CLI operations like terminate-instances, delete-db-instance, and s3 rm --recursive.\n- `cloud.azure` - Protects against destructive Azure CLI operations like vm delete, storage account delete, and resource group delete.\n- `cloud.gcp` - Protects against destructive gcloud operations like instances delete, sql instances delete, and gsutil rm -r.\n\n### CDN Packs\n- `cdn.cloudflare_workers` - Protects against destructive Cloudflare Workers, KV, R2, and D1 operations via the Wrangler CLI.\n- `cdn.cloudfront` - Protects against destructive AWS CloudFront operations like deleting distributions, cache policies, and functions.\n- `cdn.fastly` - Protects against destructive Fastly CLI operations like service, domain, backend, and VCL deletion.\n\n### API Gateway Packs\n- `apigateway.apigee` - Protects against destructive Google Apigee CLI and apigeecli operations.\n- `apigateway.aws` - Protects against destructive AWS API Gateway CLI operations for both REST APIs and HTTP APIs.\n- `apigateway.kong` - Protects against destructive Kong Gateway CLI, deck CLI, and Admin API operations.\n\n### Infrastructure Packs\n- `infrastructure.ansible` - Protects against destructive Ansible operations like dangerous shell commands and unchecked playbook runs.\n- `infrastructure.pulumi` - Protects against destructive Pulumi operations like destroy and up with -y (auto-approve).\n- `infrastructure.terraform` - Protects against destructive Terraform operations like destroy, taint, and apply with -auto-approve.\n\n### System Packs\n- `system.disk` - Protects against destructive disk operations including dd to devices, mkfs, partition table modifications (fdisk/parted), RAID management (mdadm), btrfs filesystem operations, device-mapper (dmsetup), network block devices (nbd-client), and LVM commands (pvremove, vgremove, lvremove, lvreduce, pvmove).\n- `system.permissions` - Protects against dangerous permission changes like chmod 777, recursive chmod/chown on system directories.\n- `system.services` - Protects against dangerous service operations like stopping critical services and modifying init configuration.\n\n### CI/CD Packs\n- `cicd.circleci` - Protects against destructive CircleCI operations like deleting contexts, removing secrets, deleting orbs/namespaces, or removing pipelines.\n- `cicd.github_actions` - Protects against destructive GitHub Actions operations like deleting secrets/variables or using gh api DELETE against /actions endpoints.\n- `cicd.gitlab_ci` - Protects against destructive GitLab CI/CD operations like deleting variables, removing artifacts, and unregistering runners.\n- `cicd.jenkins` - Protects against destructive Jenkins CLI/API operations like deleting jobs, nodes, credentials, or build history.\n\n### Secrets Management Packs\n- `secrets.aws_secrets` - Protects against destructive AWS Secrets Manager and SSM Parameter Store operations like delete-secret and delete-parameter.\n- `secrets.doppler` - Protects against destructive Doppler CLI operations like deleting secrets, configs, environments, or projects.\n- `secrets.onepassword` - Protects against destructive 1Password CLI operations like deleting items, documents, users, groups, and vaults.\n- `secrets.vault` - Protects against destructive Vault CLI operations like deleting secrets, disabling auth/secret engines, revoking leases/tokens, and deleting policies.\n\n### Platform Packs\n- `platform.github` - Protects against destructive GitHub CLI operations like deleting repositories, gists, releases, or SSH keys.\n- `platform.gitlab` - Protects against destructive GitLab platform operations like deleting projects, releases, protected branches, and webhooks.\n\n### DNS Packs\n- `dns.cloudflare` - Protects against destructive Cloudflare DNS operations like record deletion, zone deletion, and targeted Terraform destroy.\n- `dns.generic` - Protects against destructive or risky DNS tooling usage (nsupdate deletes, zone transfers).\n- `dns.route53` - Protects against destructive AWS Route53 DNS operations like hosted zone deletion and record set DELETE changes.\n\n### Email Packs\n- `email.mailgun` - Protects against destructive Mailgun API operations like domain deletion, route deletion, and mailing list removal.\n- `email.postmark` - Protects against destructive Postmark API operations like server deletion, template deletion, and sender signature removal.\n- `email.sendgrid` - Protects against destructive SendGrid API operations like template deletion, API key deletion, and domain authentication removal.\n- `email.ses` - Protects against destructive AWS Simple Email Service operations like identity deletion, template deletion, and configuration set removal.\n\n### Feature Flag Packs\n- `featureflags.flipt` - Protects against destructive Flipt CLI and API operations.\n- `featureflags.launchdarkly` - Protects against destructive LaunchDarkly CLI and API operations.\n- `featureflags.split` - Protects against destructive Split.io CLI and API operations.\n- `featureflags.unleash` - Protects against destructive Unleash CLI and API operations.\n\n### Load Balancer Packs\n- `loadbalancer.elb` - Protects against destructive AWS Elastic Load Balancing (ELB/ALB/NLB) operations like deleting load balancers, target groups, or deregistering targets from live traffic.\n- `loadbalancer.haproxy` - Protects against destructive HAProxy load balancer operations like stopping the service or disabling backends via runtime API.\n- `loadbalancer.nginx` - Protects against destructive nginx load balancer operations like stopping the service or deleting config files.\n- `loadbalancer.traefik` - Protects against destructive Traefik load balancer operations like stopping containers, deleting config, or API deletions.\n\n### Messaging Packs\n- `messaging.kafka` - Protects against destructive Kafka CLI operations like deleting topics, removing consumer groups, resetting offsets, and deleting records.\n- `messaging.nats` - Protects against destructive NATS/JetStream operations like deleting streams, consumers, key-value entries, objects, and accounts.\n- `messaging.rabbitmq` - Protects against destructive RabbitMQ operations like deleting queues/exchanges, purging queues, deleting vhosts, and resetting cluster state.\n- `messaging.sqs_sns` - Protects against destructive AWS SQS and SNS operations like deleting queues, purging messages, deleting topics, and removing subscriptions.\n\n### Monitoring Packs\n- `monitoring.datadog` - Protects against destructive Datadog CLI/API operations like deleting monitors and dashboards.\n- `monitoring.newrelic` - Protects against destructive New Relic CLI/API operations like deleting entities or alerting resources.\n- `monitoring.pagerduty` - Protects against destructive PagerDuty CLI/API operations like deleting services and schedules (which can break incident routing).\n- `monitoring.prometheus` - Protects against destructive Prometheus/Grafana operations like deleting time series data or dashboards/datasources.\n- `monitoring.splunk` - Protects against destructive Splunk CLI/API operations like index removal and REST API DELETE calls.\n\n### Payment Packs\n- `payment.braintree` - Protects against destructive Braintree/PayPal payment operations like deleting customers or cancelling subscriptions via API/SDK calls.\n- `payment.square` - Protects against destructive Square CLI/API operations like deleting catalog objects or customers (which can break payment flows).\n- `payment.stripe` - Protects against destructive Stripe CLI/API operations like deleting webhook endpoints and customers, or rotating API keys without coordination.\n\n### Search Engine Packs\n- `search.algolia` - Protects against destructive Algolia operations like deleting indices, clearing objects, removing rules/synonyms, and deleting API keys.\n- `search.elasticsearch` - Protects against destructive Elasticsearch REST API operations like index deletion, delete-by-query, index close, and cluster setting changes.\n- `search.meilisearch` - Protects against destructive Meilisearch REST API operations like index deletion, document deletion, delete-batch, and API key removal.\n- `search.opensearch` - Protects against destructive OpenSearch REST API operations and AWS CLI domain deletions.\n\n### Backup Packs\n- `backup.borg` - Protects against destructive borg operations like delete, prune, compact, and recreate.\n- `backup.rclone` - Protects against destructive rclone operations like sync, delete, purge, dedupe, and move.\n- `backup.restic` - Protects against destructive restic operations like forgetting snapshots, pruning data, removing keys, and cache cleanup.\n- `backup.velero` - Protects against destructive velero operations like deleting backups, schedules, and locations.\n\n### Other Packs\n- `package_managers` - Protects against dangerous package manager operations like publishing packages and removing critical system packages.\n- `strict_git` - Stricter git protections: blocks all force pushes, rebases, and history rewriting operations.\n\nEnable packs in `~/.config/dcg/config.toml`:\n\n```toml\n[packs]\nenabled = [\n    # Databases\n    \"database.postgresql\",\n    \"database.redis\",\n\n    # Containers and orchestration\n    \"containers.docker\",\n    \"kubernetes\",  # Enables all kubernetes sub-packs\n\n    # Cloud providers\n    \"cloud.aws\",\n    \"cloud.gcp\",\n\n    # Secrets management\n    \"secrets.aws_secrets\",\n    \"secrets.vault\",\n\n    # CI/CD\n    \"cicd.jenkins\",\n    \"cicd.gitlab_ci\",\n\n    # Messaging\n    \"messaging.kafka\",\n    \"messaging.sqs_sns\",\n\n    # Search engines\n    \"search.elasticsearch\",\n\n    # Backup\n    \"backup.restic\",\n\n    # Platform\n    \"platform.github\",\n\n    # Monitoring\n    \"monitoring.splunk\",\n]\n```\n\n### Custom Packs\n\nCreate your own organization-specific security packs using YAML files. Custom packs let you define patterns for internal tools, deployment scripts, and proprietary systems without modifying dcg.\n\n```toml\n[packs]\ncustom_paths = [\n    \"~/.config/dcg/packs/*.yaml\",      # User packs\n    \".dcg/packs/*.yaml\",               # Project-local packs\n]\n```\n\nFor detailed pack authoring guide, schema reference, and examples, see [`docs/custom-packs.md`](docs/custom-packs.md).\n\nValidate your pack before deployment:\n\n```bash\ndcg pack validate mypack.yaml\n```\n\nHeredoc scanning configuration:\n\n```toml\n[heredoc]\n# Enable scanning for heredocs and inline scripts (python -c, bash -c, etc.).\nenabled = true\n\n# Extraction timeout budget (milliseconds).\ntimeout_ms = 50\n\n# Resource limits for extracted bodies.\nmax_body_bytes = 1048576\nmax_body_lines = 10000\nmax_heredocs = 10\n\n# Optional language filter (scan only these languages). Omit for \"all\".\n# languages = [\"python\", \"bash\", \"javascript\", \"typescript\", \"ruby\", \"perl\", \"go\"]\n\n# Graceful degradation (hook defaults are fail-open).\nfallback_on_parse_error = true\nfallback_on_timeout = true\n```\n\nCLI overrides for heredoc scanning:\n\n- `--heredoc-scan` / `--no-heredoc-scan`\n- `--heredoc-timeout \u003cms\u003e`\n- `--heredoc-languages \u003clang1,lang2,...\u003e`\n\nHeredoc documentation:\n\n- `docs/adr-001-heredoc-scanning.md` (architecture and rationale)\n- `docs/patterns.md` (pattern authoring + inventory)\n- `docs/security.md` (threat model and incident response)\n\n#### Heredoc Three-Tier Architecture\n\nHeredoc and inline script scanning uses a three-tier pipeline designed for performance and accuracy:\n\n```\nCommand Input\n     │\n     ▼\n┌─────────────────┐\n│ Tier 1: Trigger │ ─── No match ──► ALLOW (fast path, \u003c100μs)\n│   (RegexSet)    │\n└────────┬────────┘\n         │ Match\n         ▼\n┌─────────────────┐\n│ Tier 2: Extract │ ─── Error/Timeout ──► ALLOW + fallback check\n│   (\u003c1ms)        │\n└────────┬────────┘\n         │ Success\n         ▼\n┌─────────────────┐\n│ Tier 3: AST     │ ─── No match ──► ALLOW\n│   (\u003c5ms)        │ ─── Match ──► BLOCK\n└─────────────────┘\n```\n\n**Tier 1: Trigger Detection** (\u003c100μs)\n\nUltra-fast regex screening to detect heredoc indicators. Uses a compiled `RegexSet` for O(n) matching against all trigger patterns simultaneously:\n\n```rust\nstatic HEREDOC_TRIGGERS: LazyLock\u003cRegexSet\u003e = LazyLock::new(|| {\n    RegexSet::new([\n        r\"\u003c\u003c-?\\s*(?:['\\x22][^'\\x22]*['\\x22]|[\\w.-]+)\",  // Heredocs\n        r\"\u003c\u003c\u003c\",                                          // Here-strings\n        r\"\\bpython[0-9.]*\\b.*\\s+-[A-Za-z]*[ce]\",        // python -c/-e\n        r\"\\bruby[0-9.]*\\b.*\\s+-[A-Za-z]*e\",             // ruby -e\n        r\"\\bnode(js)?[0-9.]*\\b.*\\s+-[A-Za-z]*[ep]\",     // node -e/-p\n        r\"\\b(sh|bash|zsh)\\b.*\\s+-[A-Za-z]*c\",           // bash -c\n        // ... more patterns\n    ])\n});\n```\n\nCommands without any trigger patterns skip directly to ALLOW—no further processing needed.\n\n**Tier 2: Content Extraction** (\u003c1ms)\n\nFor commands that trigger, extract the actual content to be evaluated:\n\n- **Heredocs**: `cat \u003c\u003cEOF ... EOF` → extracts body between delimiters\n- **Here-strings**: `cat \u003c\u003c\u003c \"content\"` → extracts quoted content\n- **Inline scripts**: `python -c \"code\"` → extracts the code argument\n\nExtraction is bounded by configurable limits:\n- Maximum body size (default: 1MB)\n- Maximum lines (default: 10,000)\n- Maximum heredocs per command (default: 10)\n- Timeout (default: 50ms)\n\n```rust\npub struct ExtractionLimits {\n    pub max_body_bytes: usize,\n    pub max_body_lines: usize,\n    pub max_heredocs: usize,\n    pub timeout_ms: u64,\n}\n```\n\n**Tier 3: AST Pattern Matching** (\u003c5ms)\n\nExtracted content is parsed using language-specific AST grammars (via tree-sitter/ast-grep) and matched against structural patterns:\n\n```rust\n// Example: detect subprocess.run with shell=True and rm -rf\nlet pattern = r#\"\n    call_expression {\n        function: attribute { object: \"subprocess\" attr: \"run\" }\n        arguments: argument_list {\n            contains string { contains \"rm -rf\" }\n            contains keyword_argument { keyword: \"shell\" value: \"True\" }\n        }\n    }\n\"#;\n```\n\n**Recursive Shell Analysis**:\n\nWhen extracted content is itself a shell script (e.g., `bash -c \"git reset --hard\"`), Tier 3 recursively extracts inner commands and re-evaluates them through the full pipeline:\n\n```rust\nif content.language == ScriptLanguage::Bash {\n    let inner_commands = extract_shell_commands(\u0026content.content);\n    for inner in inner_commands {\n        // Re-evaluate inner command against all packs\n        if let Some(result) = evaluate_command(\u0026inner, ...) {\n            if result.decision == Deny {\n                return result; // Block the outer command\n            }\n        }\n    }\n}\n```\n\nIf you encounter commands that should be blocked, please file an issue.\n\n### Environment Variables\n\nEnvironment variables override config files (highest priority):\n\n- `DCG_PACKS=\"containers.docker,kubernetes\"`: enable packs (comma-separated)\n- `DCG_DISABLE=\"kubernetes.helm\"`: disable packs/sub-packs (comma-separated)\n- `DCG_VERBOSE=0-3`: verbosity level (0 = quiet, 3 = trace)\n- `DCG_QUIET=1`: suppress non-error output\n- `DCG_COLOR=auto|always|never`: color mode\n- `DCG_NO_COLOR=1`: disable colored output (same as NO_COLOR)\n- `DCG_HIGH_CONTRAST=1`: enable high-contrast output (ASCII borders + monochrome palette)\n- `DCG_FORMAT=text|json|sarif`: default output format (command-specific; SARIF applies to `dcg scan`)\n- `DCG_BYPASS=1`: bypass dcg entirely (escape hatch; use sparingly)\n- `DCG_CONFIG=/path/to/config.toml`: use explicit config file\n- `DCG_HEREDOC_ENABLED=true|false`: enable/disable heredoc scanning\n- `DCG_HEREDOC_TIMEOUT=50`: heredoc extraction timeout (milliseconds)\n- `DCG_HEREDOC_TIMEOUT_MS=50`: heredoc extraction timeout (milliseconds)\n- `DCG_HEREDOC_LANGUAGES=python,bash`: filter heredoc languages\n- `DCG_POLICY_DEFAULT_MODE=deny|warn|log`: global default decision mode\n- `DCG_HOOK_TIMEOUT_MS=200`: hook evaluation timeout budget (milliseconds)\n\n### Configuration Hierarchy\n\ndcg supports layered configuration from multiple sources, with higher-priority sources overriding lower ones:\n\n1. Environment Variables (DCG_* prefix)           [HIGHEST PRIORITY]\n2. Explicit Config File (DCG_CONFIG env var)\n3. Project Config (.dcg.toml in repo root)\n4. User Config (~/.config/dcg/config.toml)\n5. System Config (/etc/dcg/config.toml)\n6. Compiled Defaults                              [LOWEST PRIORITY]\n\n### Accessibility \u0026 Themes\n\ndcg supports colorblind-safe palettes and high-contrast output. Colors are always paired\nwith symbols/labels to avoid conveying meaning by color alone.\n\n```toml\n[output]\nhigh_contrast = true       # ASCII borders + black/white palette\n\n[theme]\npalette = \"colorblind\"     # default | colorblind | high-contrast\nuse_unicode = true         # false for ASCII-only\nuse_color = true           # false for monochrome\n```\n\n**Configuration File Locations**:\n\n| Level | Path | Use Case |\n|-------|------|----------|\n| System | `/etc/dcg/config.toml` | Organization-wide defaults |\n| User | `~/.config/dcg/config.toml` | Personal preferences |\n| Project | `.dcg.toml` (repo root) | Project-specific settings |\n| Explicit | `DCG_CONFIG=/path/to/file` | Testing or override |\n\n**Merging Behavior**:\n\nConfiguration layers are merged additively, with higher-priority sources overriding specific fields:\n\n```rust\n// Only fields explicitly set in higher-priority configs override\n// Missing fields retain values from lower-priority sources\nfn merge_layer(\u0026mut self, other: ConfigLayer) {\n    if let Some(verbose) = other.general.verbose {\n        self.general.verbose = verbose;  // Override if present\n    }\n    // Unset fields retain previous values\n}\n```\n\nThis means you can set organization defaults in `/etc/dcg/config.toml`, personal preferences in `~/.config/dcg/config.toml`, and project-specific overrides in `.dcg.toml`—each layer only needs to specify the settings that differ from defaults.\n\n**Project-Specific Pack Configuration**:\n\nThe `[projects]` section allows different pack configurations for different repositories:\n\n```toml\n[projects.\"/home/user/work/production-api\"]\npacks = { enabled = [\"database.postgresql\", \"cloud.aws\"], disabled = [] }\n\n[projects.\"/home/user/personal/experiments\"]\npacks = { enabled = [], disabled = [\"core.git\"] }  # More permissive for experiments\n```\n\n### Fail-Open Philosophy\n\ndcg is designed with a **fail-open** philosophy: when the tool cannot safely analyze a command (due to timeouts, parse errors, or resource limits), it allows the command to proceed rather than blocking it and breaking the user's workflow.\n\n**Why Fail-Open?**\n\n1. **Workflow Continuity**: A blocked legitimate command is more disruptive than a missed dangerous one\n2. **Performance Guarantees**: The hook must never become a bottleneck\n3. **Graceful Degradation**: Partial analysis is better than no analysis\n\n**Fail-Open Scenarios**:\n\n| Scenario | Behavior | Rationale |\n|----------|----------|-----------|\n| Parse error in heredoc | ALLOW + warn | Malformed input shouldn't block work |\n| Extraction timeout | ALLOW + warn | Slow inputs shouldn't hang terminal |\n| Size limit exceeded | ALLOW + fallback check | Large inputs get reduced analysis |\n| Regex engine timeout | ALLOW + warn | Pathological patterns shouldn't block |\n| AST matching error | Skip that heredoc | Continue evaluating other content |\n| Deadline exceeded | ALLOW immediately | Hard cap prevents runaway processing |\n\n**Configurable Strictness**:\n\nFor high-security environments, fail-open can be disabled:\n\n```toml\n[heredoc]\nfallback_on_parse_error = false  # Block on parse errors\nfallback_on_timeout = false      # Block on timeouts\n```\n\nWith strict mode enabled, dcg will block commands when analysis fails, providing detailed error messages explaining why.\n\n**Fallback Pattern Checking**:\n\nEven when full analysis is skipped, dcg performs a lightweight fallback check for critical destructive patterns:\n\n```rust\nstatic FALLBACK_PATTERNS: LazyLock\u003cRegexSet\u003e = LazyLock::new(|| {\n    RegexSet::new([\n        r\"shutil\\.rmtree\",\n        r\"os\\.remove\",\n        r\"fs\\.rmSync\",\n        r\"\\brm\\s+-[a-zA-Z]*r[a-zA-Z]*f\",\n        r\"\\bgit\\s+reset\\s+--hard\\b\",\n        // ... other critical patterns\n    ])\n});\n```\n\nThis ensures that even oversized or malformed inputs are checked for the most dangerous operations before being allowed.\n\n**Absolute Timeout**:\n\nTo prevent any single command from blocking indefinitely, dcg enforces an absolute maximum processing time of **200ms**. Any command exceeding this threshold is immediately allowed with a warning logged.\n\n## Installation\n\n### Quick Install (Recommended)\n\nThe easiest way to install is using the install script, which downloads a prebuilt binary for your platform:\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | bash -s -- --easy-mode\n```\n\nEasy mode automatically:\n- Updates your PATH in shell rc files\n- Removes the legacy Python predecessor (if present)\n- Configures Claude Code hooks (creates config if needed)\n- Configures Gemini CLI hooks (if Gemini CLI is installed)\n- Configures GitHub Copilot CLI hooks in `.github/hooks/dcg.json` (if Copilot is installed and you're in a git repo)\n- Configures Aider (enables git hooks via `git-commit-verify: true`)\n- Detects Continue (no auto-config; lacks shell command hooks)\n- Detects Codex CLI (no auto-config; lacks pre-execution hooks)\n\n**Other options:**\n\nInteractive mode (prompts for each step):\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | bash\n```\n\nInstall specific version:\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | bash -s -- --version v0.1.0\n```\n\nInstall to /usr/local/bin (system-wide, requires sudo):\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | sudo bash -s -- --system\n```\n\nBuild from source instead of downloading binary:\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | bash -s -- --from-source\n```\n\nDownload/install only (skip agent hook configuration):\n\n```bash\ncurl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)\" | bash -s -- --no-configure\n```\n\n\u003e **Note:** If you have [gum](https://github.com/charmbracelet/gum) installed, the installer will use it for fancy terminal formatting.\n\nThe install script:\n- Automatically detects your OS and architecture\n- Downloads the appropriate prebuilt binary\n- Verifies SHA256 checksums for security\n- Verifies Sigstore cosign bundles when available (falls back to checksum-only if cosign is missing)\n- Falls back to building from source if no prebuilt is available\n- Detects and removes legacy Python predecessor (`git_safety_guard.py`)\n- Configures Claude Code hooks (creates config directory if needed)\n- Configures Gemini CLI hooks (if already installed)\n- Configures GitHub Copilot CLI hooks in `.github/hooks/dcg.json` (if installed and run from a git repo)\n- Configures Aider (enables `git-commit-verify` for git hook support)\n- Detects Continue (reports it has no shell command hooks)\n- Detects Codex CLI (reports it has no pre-execution hooks)\n- Offers to update your PATH\n- Skips agent configuration when `--no-configure` is provided\n\n\u003e **Note on Aider:** Aider does not have PreToolUse-style shell command interception like Claude Code. The installer enables `git-commit-verify: true` in `~/.aider.conf.yml`, which ensures git hooks run (Aider defaults to bypassing them). For full protection, install dcg as a [git pre-commit hook](docs/scan-precommit-guide.md).\n\n\u003e **Note on Continue:** Continue does not have shell command interception hooks. The installer detects Continue installations but cannot auto-configure protection. For dcg protection with Continue, install dcg as a [git pre-commit hook](docs/scan-precommit-guide.md).\n\n\u003e **Note on Codex CLI:** OpenAI's Codex CLI only supports post-execution hooks (`notify`, `agent-turn-complete`), not pre-execution command interception. The installer detects Codex CLI but cannot auto-configure protection. For dcg protection with Codex CLI, install dcg as a [git pre-commit hook](docs/scan-precommit-guide.md).\n\n\u003e **Note on GitHub Copilot CLI:** Copilot hooks are repository-local (`.github/hooks/*.json`) and loaded from the current working directory. Run the installer from each repository where you want protection so it can create/merge `.github/hooks/dcg.json`.\n\n\u003e **Recommended:** After installing, run `dcg setup` (or re-run the installer) to add a [shell startup check](#hook-silently-removed-recommended-add-shell-startup-check) that warns you if the dcg hook is ever silently removed from `~/.claude/settings.json`.\n\n### From source (requires Rust nightly)\n\nThis project uses Rust Edition 2024 features and requires the nightly toolchain. The repository includes a `rust-toolchain.toml` that automatically selects the correct toolchain.\n\n```bash\n# Install Rust nightly if you don't have it\nrustup install nightly\n\n# Install directly from GitHub (package name required due to workspace)\ncargo +nightly install --git https://github.com/Dicklesworthstone/destructive_command_guard destructive_command_guard\n```\n\n### Manual build\n\n```bash\ngit clone https://github.com/Dicklesworthstone/destructive_command_guard\ncd destructive_command_guard\n# rust-toolchain.toml automatically selects nightly\ncargo build --release\ncp target/release/dcg ~/.local/bin/\n```\n\n## Updating\n\nRun the built-in updater to re-run the installer for your platform:\n\n```bash\ndcg update\n```\n\nOptional flags mirror the installer scripts (examples):\n\n```bash\ndcg update --version v0.2.7\ndcg update --system\ndcg update --verify\n```\n\nYou can always re-run `install.sh` / `install.ps1` directly if preferred.\n\n### Prebuilt Binaries\n\nPrebuilt binaries are available for:\n- Linux x86_64 (`x86_64-unknown-linux-gnu`)\n- Linux ARM64 (`aarch64-unknown-linux-gnu`)\n- macOS Intel (`x86_64-apple-darwin`)\n- macOS Apple Silicon (`aarch64-apple-darwin`)\n- Windows (`x86_64-pc-windows-msvc`)\n\nDownload from [GitHub Releases](https://github.com/Dicklesworthstone/destructive_command_guard/releases) and verify the SHA256 checksum.\nIf you have cosign installed, each release also includes a Sigstore bundle (`.sigstore.json`) so you can verify provenance with `cosign verify-blob`.\n\n## Uninstalling\n\nRemove dcg and all its hooks from AI agents:\n\n```bash\ncurl -fsSL https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/uninstall.sh | bash\n```\n\nThe uninstaller:\n- Removes dcg hooks from Claude Code, Gemini CLI, GitHub Copilot CLI (repo-local), and Aider\n- Removes the dcg binary\n- Removes configuration (`~/.config/dcg/`) and history (`~/.local/share/dcg/`)\n- Prompts for confirmation before making changes\n\nOptions:\n- `--yes` - Skip confirmation prompt\n- `--keep-config` - Preserve configuration files\n- `--keep-history` - Preserve history database\n- `--purge` - Remove everything (overrides keep flags)\n\n## Claude Code Configuration\n\nAdd to `~/.claude/settings.json`:\n\n```json\n{\n  \"hooks\": {\n    \"PreToolUse\": [\n      {\n        \"matcher\": \"Bash\",\n        \"hooks\": [\n          {\n            \"type\": \"command\",\n            \"command\": \"dcg\"\n          }\n        ]\n      }\n    ]\n  }\n}\n```\n\n**Important:** Restart Claude Code after adding the hook configuration.\n\n## Gemini CLI Configuration\n\nAdd to `~/.gemini/settings.json`:\n\n```json\n{\n  \"hooks\": {\n    \"BeforeTool\": [\n      {\n        \"matcher\": \"run_shell_command\",\n        \"hooks\": [\n          {\n            \"name\": \"dcg\",\n            \"type\": \"command\",\n            \"command\": \"dcg\",\n            \"timeout\": 5000\n          }\n        ]\n      }\n    ]\n  }\n}\n```\n\n**Important:** Restart Gemini CLI after adding the hook configuration.\n\n## CLI Usage\n\nWhile primarily designed as a hook, the binary supports direct invocation for testing, debugging, and understanding why commands are blocked or allowed.\n\n```bash\n# Show version with build metadata\ndcg --version\n\n# Show help with blocked command categories\ndcg --help\n\n# Test a command manually (pipe JSON to stdin)\necho '{\"tool_name\":\"Bash\",\"tool_input\":{\"command\":\"git reset --hard\"}}' | dcg\n```\n\n### Test Mode (`dcg test`)\n\nUse `dcg test` to evaluate a command **without executing it**. This is useful for CI checks, false-positive debugging, and config validation before rollout.\n\n#### Basic Usage\n\n```bash\n# Basic evaluation (human-readable output)\ndcg test \"rm -rf ./build\"\n\n# Structured output for automation\ndcg test --format json \"kubectl delete namespace prod\" | jq -r .decision\n\n# Use a specific config file\ndcg test --config .dcg.prod.toml \"docker system prune\"\n\n# Temporarily enable extra packs only for this test run\ndcg test --with-packs containers.docker,database.postgresql \"docker system prune\"\n\n# Print full evaluation trace (same engine as `dcg explain`)\ndcg test --explain \"git reset --hard\"\n```\n\n#### Exit Codes\n\n- `0`: command would be allowed\n- `1`: command would be blocked\n\n#### Flags and Options\n\n- `-c, --config \u003cPATH\u003e`: use a specific config file\n- `--with-packs \u003cID1,ID2\u003e`: temporarily enable extra packs\n- `--explain`: print detailed decision trace\n- `-f, --format \u003cpretty|json|toon\u003e`: output format (default: `pretty`)\n- `--no-color`: disable ANSI color output\n- `--heredoc-scan`: force-enable heredoc/inline-script scanning\n- `--no-heredoc-scan`: force-disable heredoc/inline-script scanning\n- `--heredoc-timeout \u003cMS\u003e`: override heredoc extraction timeout budget\n- `--heredoc-languages \u003cLANG1,LANG2\u003e`: limit heredoc AST scanning languages\n\n#### Output Formats\n\n- `pretty`: human-readable output with command context, matched rule info, and suggestions\n- `json`: structured payload for scripts/CI; includes metadata like `schema_version`, `dcg_version`, `command`, `decision`, rule/pack fields, and allowlist/agent context when present\n- `toon`: token-efficient structured encoding of the same payload used by `json` (useful for agent-to-agent/tool pipelines)\n\n#### CI/CD Integration Examples\n\nFail fast in shell pipelines:\n\n```bash\ndcg test --format json \"rm -rf /\" \u003e /tmp/dcg.json\njq -e '.decision == \"allow\"' /tmp/dcg.json\n```\n\nMinimal GitHub Actions step:\n\n```yaml\n- name: Validate dangerous command policy\n  run: |\n    ~/.local/bin/dcg test --format json \"git reset --hard HEAD~1\" \u003e /tmp/dcg-test.json\n    jq -e '.decision == \"allow\"' /tmp/dcg-test.json\n```\n\n#### Troubleshooting\n\n- Use `--format json` (or `DCG_FORMAT=json`) for machine parsing.\n- Add `--no-color` if logs or parsers choke on ANSI output.\n- If results differ between environments, check config precedence (`DCG_CONFIG`, project `.dcg.toml`, user/system config).\n- If a command is unexpectedly allowed, inspect active allowlists (`dcg allowlist list`) and enabled packs (`dcg packs --verbose`).\n- For full decision traces, run `dcg test --explain \"\u003ccommand\u003e\"` (or `dcg explain \"\u003ccommand\u003e\"`).\n\n### Explain Mode\n\nWhen you need to understand exactly why a command was blocked (or allowed), the `dcg explain` command provides a detailed trace of the decision-making process:\n\n```bash\n# Explain why a command is blocked\ndcg explain \"git reset --hard HEAD\"\n\n# Explain a safe command\ndcg explain \"git status\"\n\n# Explain with verbose timing information\ndcg explain --verbose \"rm -rf /tmp/build\"\n\n# Output as JSON for programmatic use\ndcg explain --format json \"kubectl delete namespace production\"\n```\n\nJSON output is versioned via `schema_version` (currently 2). v2 adds\n`matched_span`, `matched_text_preview`, and `explanation` in the `match`\nobject when a pattern is detected.\n\n**Example Output**:\n\n```\nCommand: git reset --hard HEAD\nNormalized: git reset --hard HEAD\n\nDecision: BLOCKED\n  Pack: core.git\n  Rule: reset-hard\n  Reason: git reset --hard destroys uncommitted changes\n\nEvaluation Trace:\n  [  0.8μs] Quick reject: passed (contains 'git')\n  [  2.1μs] Normalize: no changes\n  [  5.3μs] Safe patterns: no match (checked 34 patterns)\n  [ 12.7μs] Destructive patterns: MATCH at pattern 'reset-hard'\n  [ 12.9μs] Total time: 12.9μs\n\nSuggestion: Consider using 'git stash' first to save your changes.\n```\n\nThe explain mode shows:\n- **Normalized command**: How dcg sees the command after path normalization\n- **Decision**: Whether the command would be blocked or allowed\n- **Matching rule**: Which pack and pattern triggered the decision\n- **Evaluation trace**: Step-by-step timing of each evaluation stage\n- **Suggestion**: Actionable guidance for safer alternatives\n\nThis is invaluable for debugging false positives, understanding pack coverage, and verifying that custom allowlist entries work as expected.\n\n### Allow-Once (Temporary Exceptions)\n\nSometimes you need to run a blocked command temporarily without permanently modifying your allowlist. The allow-once system provides short codes:\n\n```bash\n# When a command is blocked, dcg outputs a short code\n# BLOCKED: git reset --hard HEAD\n# Allow-once code: ab12\n# To allow this: dcg allow-once ab12\n\n# Use the short code to create a temporary exception\ndcg allow-once ab12\n\n# Or, use --single-use to make the exception one-shot\ndcg allow-once ab12 --single-use\n```\n\n**How Allow-Once Works**:\n\n1. When dcg blocks a command, it generates a short code (currently 4 hex chars; collisions are handled via `--pick` / `--hash`)\n2. The code is tied to the exact command that was blocked\n3. Running `dcg allow-once \u003ccode\u003e` creates a temporary exception\n4. The exception is stored in `~/.config/dcg/pending_exceptions.jsonl`\n5. Exceptions expire after 24 hours (or after first use if `--single-use` is used)\n6. While active, the exception allows the same command in the same directory scope\n\nThis workflow is useful for:\n- One-time administrative operations that are intentionally destructive\n- Migration scripts that need to reset state\n- Emergency fixes where permanent allowlist changes aren't appropriate\n\n**Security Considerations**:\n- Short codes are derived from SHA256 (or optional HMAC-SHA256 when `DCG_ALLOW_ONCE_SECRET` is set)\n- Codes are never logged or transmitted\n- The pending exceptions file is readable only by the current user\n- Expired codes are automatically cleaned up\n\nThe `--version` output includes build metadata for debugging:\n\n```\ndcg 0.1.0\n  Built: 2026-01-07T22:13:10.413872881Z\n  Rustc: 1.94.0-nightly\n  Target: x86_64-unknown-linux-gnu\n```\n\nThis metadata is embedded at compile time via [vergen](https://github.com/rustyhorde/vergen), making it easy to identify exactly which build is running when troubleshooting.\n\n## Repository Scanning\n\nWhile the hook protects **interactive** command execution, teams also need protection against destructive commands that get **committed into repositories**. The `dcg scan` command extracts executable command contexts from files and evaluates them using the same pattern engine.\n\n### What Scan Is (and Is Not)\n\n**What it is:**\n- An extractor-based scanner that understands executable contexts\n- Uses the same evaluator as hook mode for consistency\n- Supports CI integration and pre-commit hooks\n\n**What it is NOT:**\n- A naive grep that matches strings everywhere\n- A replacement for code review\n- A static analysis tool for arbitrary languages\n\nThe key difference from grep: `dcg scan` understands that `\"rm -rf /\"` in a comment is data, not code. It uses extractors that understand file structure (shell scripts, Dockerfiles, GitHub Actions, Makefiles) to find only actually-executed commands.\n\n### Supported File Formats\n\ndcg scan includes specialized extractors for each file format, understanding which parts contain executable commands:\n\n| File Type | Detection | Executable Contexts |\n|-----------|-----------|---------------------|\n| **Shell Scripts** | `*.sh`, `*.bash`, `*.zsh` | All non-comment, non-assignment lines |\n| **Dockerfile** | `Dockerfile`, `*.dockerfile` | `RUN` instructions (shell and exec forms) |\n| **GitHub Actions** | `.github/workflows/*.yml` | `run:` fields in steps |\n| **GitLab CI** | `.gitlab-ci.yml` | `script:`, `before_script:`, `after_script:` |\n| **Makefile** | `Makefile` | Tab-indented recipe lines |\n| **Terraform** | `*.tf` | `provisioner` blocks (`local-exec`, `remote-exec`) |\n| **Docker Compose** | `docker-compose.yml`, `compose.yml` | `command:` and `entrypoint:` fields |\n\n**Context-Aware Extraction**:\n\nEach extractor understands its format's semantics:\n\n```yaml\n# GitHub Actions - only 'run:' is extracted\n- name: Build\n  run: |                    # ← Extracted\n    npm install\n    npm run build\n  env:\n    NODE_ENV: production    # ← Skipped (not executable)\n```\n\n```dockerfile\n# Dockerfile - only RUN instructions\nFROM node:18\nCOPY . /app                 # ← Skipped\nRUN npm install             # ← Extracted\nRUN [\"node\", \"server.js\"]   # ← Extracted (exec form)\nENV PORT=3000               # ← Skipped\n```\n\n```makefile\n# Makefile - tab-indented lines under targets\nbuild:\n\tnpm install             # ← Extracted (recipe line)\n\tnpm run build           # ← Extracted\nSOURCES = $(wildcard *.js)  # ← Skipped (variable assignment)\n```\n\n**Non-Executable Context Filtering**:\n\nExtractors intelligently skip data-only sections:\n\n- **Shell**: Assignment-only lines (`export VAR=value`)\n- **YAML**: `environment:`, `labels:`, `volumes:`, `variables:` blocks\n- **Terraform**: Everything outside `provisioner` blocks\n- **All formats**: Comments (format-appropriate: `#`, `//`, etc.)\n\n### Quick Start\n\n```bash\n# Install the pre-commit hook\ndcg scan install-pre-commit\n\n# Or manually run on staged files\ndcg scan --staged\n\n# Scan specific paths\ndcg scan --paths scripts/ .github/workflows/\n```\n\n### Recommended Rollout Plan\n\n**Start conservative to avoid developer friction:**\n\n```bash\n# Week 1-2: Warn-first with narrow scope\ndcg scan --staged --fail-on error  # Only fail on catastrophic rules\n```\n\nCreate `.dcg/hooks.toml` with conservative defaults:\n\n```toml\n[scan]\nfail_on = \"error\"          # Only fail on high-confidence catastrophic rules\nformat = \"pretty\"          # Human-readable output\nredact = \"quoted\"          # Hide sensitive strings\ntruncate = 120             # Shorten long commands\n\n[scan.paths]\ninclude = [\n    \".github/workflows/**\",  # Start with CI configs\n    \"Dockerfile\",            # Container builds\n    \"Makefile\",              # Build scripts\n]\nexclude = [\n    \"target/**\",\n    \"node_modules/**\",\n    \"vendor/**\",\n]\n```\n\n**Gradual expansion:**\n\n1. **Week 1-2**: Start with workflows/Dockerfiles only, `--fail-on error`\n2. **Week 3-4**: Add Makefiles and shell scripts in `scripts/`\n3. **Month 2**: Add `--fail-on warning` after reviewing findings\n4. **Ongoing**: Add new extractors as team confidence grows\n\n### Pre-Commit Integration\n\n#### One-Command Install\n\n```bash\ndcg scan install-pre-commit\n```\n\nThis creates a `.git/hooks/pre-commit` that runs `dcg scan --staged`.\n\n#### Manual Setup\n\nIf you prefer manual control or use a hook manager:\n\n```bash\n#!/bin/bash\n# .git/hooks/pre-commit (or equivalent for your hook manager)\n\nset -e\n\n# Run dcg scan on staged files\ndcg scan --staged --fail-on error\n\n# Add other hooks below...\n```\n\n#### Uninstall\n\n```bash\ndcg scan uninstall-pre-commit\n```\n\nThis only removes hooks installed by dcg (detected via sentinel comment).\n\n### Interpreting Findings\n\nThe output includes:\n\n```\nscripts/deploy.sh:42:5: [ERROR] core.git:reset-hard\n  Command: git reset --hard HEAD\n  Reason: git reset --hard destroys uncommitted changes\n  Suggestion: Consider using 'git stash' first to save changes.\n```\n\n- **File:Line:Col**: Location in the source file\n- **Severity**: `ERROR` (catastrophic) or `WARNING` (concerning)\n- **Rule ID**: Stable identifier like `core.git:reset-hard`\n- **Command**: The extracted command (may be redacted/truncated)\n- **Reason**: Why this command is flagged\n- **Suggestion**: How to make it safer\n\n### Fixing Findings\n\n#### Option 1: Change the Code (Preferred)\n\nReplace the dangerous command with a safer alternative:\n\n```bash\n# Instead of:\ngit reset --hard\n\n# Use:\ngit stash push -m \"before reset\"\ngit reset --hard\n```\n\n#### Option 2: Understand with Explain\n\nGet detailed analysis:\n\n```bash\ndcg explain \"git reset --hard HEAD\"\n```\n\n#### Option 3: Allowlist (When Intentional)\n\nIf the command is genuinely needed:\n\n```bash\n# Project-level allowlist (committed, code-reviewed)\ndcg allowlist add core.git:reset-hard --reason \"Required for CI cleanup\" --project\n\n# Or for a specific command\ndcg allowlist add-command \"rm -rf ./build\" --reason \"Build cleanup\" --project\n```\n\nThe finding output includes a copy-paste allowlist command for convenience.\nHeredoc rules use stable IDs like `heredoc.python.shutil_rmtree`.\n\n### Privacy and Redaction\n\nScan supports redaction of potentially sensitive content in output. Use `--redact quoted` to hide quoted strings that may contain secrets:\n\n```\n# Original command:\ncurl -H \"Authorization: Bearer $TOKEN\" https://api.example.com\n\n# With --redact quoted:\ncurl -H \"...\" https://api.example.com\n```\n\nOptions:\n- `--redact none`: Show full commands (default)\n- `--redact quoted`: Hide quoted strings (recommended for CI logs)\n- `--redact aggressive`: Hide more potential secrets\n\n### Configuration Reference\n\n`.dcg/hooks.toml` (project-level, committed):\n\n```toml\n[scan]\n# Exit non-zero when findings meet this threshold\nfail_on = \"error\"      # Options: none, warning, error\n\n# Output format\nformat = \"pretty\"      # Options: pretty, json, markdown\n\n# Maximum file size to scan (bytes)\nmax_file_size = 1000000\n\n# Stop after this many findings\nmax_findings = 50\n\n# Redaction level for sensitive content\nredact = \"quoted\"      # Options: none, quoted, aggressive\n\n# Truncate long commands (chars; 0 = no truncation)\ntruncate = 120\n\n[scan.paths]\n# Only scan files matching these patterns\ninclude = [\n    \"scripts/**\",\n    \".github/workflows/**\",\n    \"Dockerfile*\",\n    \"Makefile\",\n]\n\n# Skip files matching these patterns\nexclude = [\n    \"target/**\",\n    \"node_modules/**\",\n    \"*.md\",\n]\n```\n\nCLI flags override config file values.\n\n### CI Integration\n\n#### GitHub Actions\n\n```yaml\nname: Security Scan\non: [pull_request]\n\njobs:\n  scan:\n    runs-on: ubuntu-latest\n    steps:\n      - uses: actions/checkout@v4\n        with:\n          fetch-depth: 0\n\n      - name: Install dcg\n        run: |\n          curl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh\" | bash\n          echo \"$HOME/.local/bin\" \u003e\u003e $GITHUB_PATH\n\n      - name: Scan changed files\n        run: |\n          dcg scan --git-diff origin/${{ github.base_ref }}..HEAD \\\n            --format markdown \\\n            --fail-on error\n```\n\n#### GitLab CI\n\n```yaml\nscan:\n  stage: test\n  script:\n    - curl -fsSL \"https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh\" | bash\n    - ~/.local/bin/dcg scan --git-diff origin/$CI_MERGE_REQUEST_TARGET_BRANCH_NAME..HEAD --fail-on error\n  rules:\n    - if: $CI_MERGE_REQUEST_ID\n```\n\n### Bypass for Emergencies\n\nIf you need to bypass the pre-commit hook temporarily:\n\n```bash\ngit commit --no-verify -m \"Emergency fix\"\n```\n\nThis is logged and visible in git history. For permanent exceptions, use allowlists instead.\n\n## How It Works\n\n1. Claude Code, Gemini CLI, or GitHub Copilot CLI invokes the hook before executing a shell command\n2. The hook receives the command as JSON on stdin\n3. Commands are normalized (e.g., `/usr/bin/git` becomes `git`)\n4. Safe patterns are checked first (whitelist approach)\n5. Destructive patterns are checked second (blacklist approach)\n6. If destructive: outputs JSON denial with explanation\n7. If safe: exits silently (no output = allow)\n\nThe hook is designed for minimal latency with sub-millisecond execution on typical commands.\n\n### Output Behavior\n\nThe hook uses two separate output channels:\n\n- **stdout (JSON)**: Hook protocol response (Claude-compatible `hookSpecificOutput`, Gemini-compatible `decision/reason`, or Copilot-compatible `continue: false` + denial fields). On allow, outputs nothing.\n- **stderr (colorful text)**: A human-readable warning when commands are blocked. Colors are automatically disabled when stderr is not a TTY (e.g., when piped to a file).\n\nThis dual-output design ensures the hook protocol works correctly while still providing immediate visual feedback to users watching the terminal.\n\n## Architecture\n\n```\n┌─────────────────────────────────────────────────────────────────┐\n│            Claude Code / Gemini CLI / Copilot CLI                │\n│                                                                  │\n│  User: \"delete the build artifacts\"                             │\n│  Agent: executes `rm -rf ./build`                               │\n│                                                                  │\n└─────────────────────┬───────────────────────────────────────────┘\n                      │\n                      ▼ PreToolUse hook (stdin: JSON)\n┌─────────────────────────────────────────────────────────────────┐\n│                     dcg                             │\n│                                                                  │\n│  ┌──────────────┐    ┌──────────────┐    ┌──────────────┐       │\n│  │    Parse     │───▶│  Normalize   │───▶│ Quick Reject │       │\n│  │    JSON      │    │   Command    │    │   Filter     │       │\n│  └──────────────┘    └──────────────┘    └──────┬───────┘       │\n│                                                  │               │\n│                      ┌───────────────────────────┘               │\n│                      ▼                                           │\n│  ┌──────────────────────────────────────────────────────────┐   │\n│  │                   Pattern Matching                        │   │\n│  │                                                           │   │\n│  │   1. Check SAFE_PATTERNS (whitelist) ──▶ Allow if match  │   │\n│  │   2. Check DESTRUCTIVE_PATTERNS ──────▶ Deny if match    │   │\n│  │   3. No match ────────────────────────▶ Allow (default)  │   │\n│  │                                                           │   │\n│  └──────────────────────────────────────────────────────────┘   │\n│                                                                  │\n└─────────────────────┬───────────────────────────────────────────┘\n                      │\n                      ▼ stdout: JSON (deny) or empty (allow)\n┌─────────────────────────────────────────────────────────────────┐\n│            Claude Code / Gemini CLI / Copilot CLI                │\n│                                                                  │\n│  If denied: Shows block message, does NOT execute command       │\n│  If allowed: Proceeds with command execution                    │\n│                                                                  │\n└─────────────────────────────────────────────────────────────────┘\n```\n\n### Context Classification System\n\nNot every occurrence of a dangerous pattern is actually dangerous. The string `git reset --hard` appearing in a comment, a heredoc body, or a quoted string is fundamentally different from the same string appearing as an executed command. dcg uses a sophisticated context classification system to reduce false positives without compromising safety.\n\n**SpanKind Classification**\n\nEvery token in a command is classified into one of these categories:\n\n| SpanKind | Description | Treatment |\n|----------|-------------|-----------|\n| `Executed` | Command words and unquoted arguments | **MUST check** - highest priority |\n| `InlineCode` | Content inside `-c`/`-e` flags (bash -c, python -c) | **MUST check** - code will be executed |\n| `Argument` | Quoted arguments to known-safe commands | Lower priority, context-dependent |\n| `Data` | Single-quoted strings (shell cannot interpolate) | **Can skip** - treated as literal data |\n| `HeredocBody` | Content inside heredocs | Escalated to Tier 2/3 heredoc scanning |\n| `Comment` | Shell comments (`# ...`) | **Skip** - never executed |\n| `Unknown` | Cannot determine context | Conservative treatment as `Executed` |\n\n**Why Context Matters**\n\nConsider these commands:\n\n```bash\n# Safe: the dangerous pattern is in a comment\necho \"Reminder: never run git reset --hard\"   # git reset --hard destroys changes\n\n# Safe: the dangerous pattern is data being searched for\ngrep \"git reset --hard\" documentation.md\n\n# Safe: the dangerous pattern is in a heredoc being written to a file\ncat \u003c\u003cEOF \u003e safety_guide.md\nWarning: git reset --hard destroys uncommitted changes\nEOF\n\n# DANGEROUS: the pattern will be executed\ngit reset --hard HEAD\n\n# DANGEROUS: the pattern is passed to bash -c for execution\nbash -c \"git reset --hard\"\n```\n\nWithout context classification, the first three examples would trigger false positives. The context classifier analyzes the AST (abstract syntax tree) structure to understand where patterns appear and only flags genuinely dangerous occurrences.\n\n**Implementation Details**\n\nThe context classifier uses a multi-pass approach:\n\n1. **Lexical Analysis**: Identify quoted strings, comments, and heredoc markers\n2. **Structural Analysis**: Build a tree of command structure, identifying pipes, subshells, and command substitutions\n3. **Flag Analysis**: Detect `-c`, `-e`, and similar flags that introduce inline code contexts\n4. **Span Annotation**: Tag each character range with its SpanKind\n\nThis approach achieves a significant reduction in false positives while maintaining the zero-false-negatives philosophy for actual command execution.\n\n### Processing Pipeline\n\n**Stage 1: JSON Parsing**\n- Reads the hook input from stdin\n- Validates supported hook payload shapes (Claude/Augment/Copilot variants)\n- Extracts command string from `tool_input.command` or Copilot `toolInput/toolArgs`\n- Non-shell tools are immediately allowed (no output)\n\n**Stage 2: Command Normalization**\n- Strips absolute paths from `git` and `rm` binaries\n- `/usr/bin/git status` → `git status`\n- `/bin/rm -rf /tmp/foo` → `rm -rf /tmp/foo`\n- Uses regex with lookahead to preserve arguments containing paths\n\n**Stage 3: Quick Rejection Filter**\n- O(n) substring search for \"git\" or \"rm\" in the command\n- Commands without these substrings bypass regex matching entirely\n- Handles 99%+ of non-destructive commands (ls, cat, cargo, npm, etc.)\n\n**Stage 4: Pattern Matching**\n- Safe patterns checked first (short-circuit on match → allow)\n- Destructive patterns checked second (match → deny with reason)\n- No match on either → default allow\n\n## Design Principles\n\n### 1. Whitelist-First Architecture\n\nSafe patterns are checked *before* destructive patterns. This design ensures that explicitly safe commands (like `git checkout -b`) are never accidentally blocked, even if they partially match a destructive pattern (like `git checkout`).\n\n```\ngit checkout -b feature    →  Matches SAFE \"checkout-new-branch\"  →  ALLOW\ngit checkout -- file.txt   →  No safe match, matches DESTRUCTIVE  →  DENY\n```\n\n### 2. Fail-Safe Defaults\n\nThe hook uses a **default-allow** policy for unrecognized commands. This ensures:\n- The hook never breaks legitimate workflows\n- Only *known* dangerous patterns are blocked\n- New git commands are allowed until explicitly categorized\n\n### 3. Zero False Negatives Philosophy\n\nThe pattern set prioritizes **never allowing dangerous commands** over avoiding false positives. A few extra prompts for manual confirmation are acceptable; lost work is not.\n\n### 4. Defense in Depth\n\nThis hook is one layer of protection. It complements (not replaces):\n- Regular commits and pushes\n- Git stash before risky operations\n- Proper backup strategies\n- Code review processes\n\n### 5. Minimal Latency\n\nEvery Bash command passes through this hook. Performance is critical:\n- Lazy-initialized static regex patterns (compiled once, reused)\n- Quick rejection filter eliminates 99%+ of commands before regex\n- No heap allocations on the hot path for safe commands\n- Sub-millisecond execution for typical commands\n\n## Pattern Matching System\n\n### Safe Patterns (Whitelist)\n\nThe safe pattern list contains 34 patterns covering:\n\n| Category | Patterns | Purpose |\n|----------|----------|---------|\n| Branch creation | `checkout -b`, `checkout --orphan` | Creating branches is safe |\n| Staged-only | `restore --staged`, `restore -S` | Unstaging doesn't touch working tree |\n| Dry run | `clean -n`, `clean --dry-run` | Preview mode, no actual deletion |\n| Temp cleanup | `rm -rf /tmp/*`, `rm -rf /var/tmp/*` | Ephemeral directories are safe |\n| Variable expansion | `rm -rf $TMPDIR/*`, `rm -rf ${TMPDIR}/*` | Shell variable forms |\n| Quoted paths | `rm -rf \"$TMPDIR/*\"` | Quoted variable forms |\n| Separate flags | `rm -r -f /tmp/*`, `rm -r -f $TMPDIR/*` | Flag ordering variants |\n| Long flags | `rm --recursive --force /tmp/*`, `$TMPDIR/*` | GNU-style long options |\n\n### Destructive Patterns (Blacklist)\n\nThe destructive pattern list contains 16 patterns covering:\n\n| Category | Pattern | Reason |\n|----------|---------|--------|\n| Work destruction | `reset --hard`, `reset --merge` | Destroys uncommitted changes |\n| File reversion | `checkout -- \u003cpath\u003e` | Discards file modifications |\n| Worktree restore | `restore` (without --staged) | Discards uncommitted changes |\n| Untracked deletion | `clean -f` | Permanently removes untracked files |\n| History rewrite | `push --force`, `push -f` | Can destroy remote commits |\n| Unsafe branch delete | `branch -D` | Force-deletes without merge check |\n| Stash destruction | `stash drop`, `stash clear` | Permanently deletes stashed work |\n| Filesystem nuke | `rm -rf` (non-temp paths) | Recursive deletion outside temp |\n\n### Pattern Syntax\n\nPatterns use [fancy-regex](https://github.com/fancy-regex/fancy-regex) for advanced features:\n\n```rust\n// Negative lookahead: block restore UNLESS --staged is present\nr\"git\\s+restore\\s+(?!--staged\\b)(?!-S\\b)\"\n\n// Negative lookahead: don't match --force-with-lease\nr\"git\\s+push\\s+.*--force(?![-a-z])\"\n\n// Character class: match any flag ordering\nr\"rm\\s+-[a-zA-Z]*[rR][a-zA-Z]*f[a-zA-Z]*\"\n```\n\n## Edge Cases Handled\n\n### Path Normalization\n\nCommands may use absolute paths to binaries:\n\n```bash\n/usr/bin/git reset --hard          # Blocked ✓\n/usr/local/bin/git checkout -- .   # Blocked ✓\n/bin/rm -rf /home/user             # Blocked ✓\n```\n\nThe normalizer uses regex to strip paths while preserving arguments:\n\n```bash\ngit add /usr/bin/something         # \"/usr/bin/something\" is an argument, preserved\n```\n\n### Flag Ordering Variants\n\nThe `rm` command accepts flags in many forms:\n\n```bash\nrm -rf /path          # Combined flags\nrm -fr /path          # Reversed order\nrm -r -f /path        # Separate flags\nrm -f -r /path        # Separate, reversed\nrm --recursive --force /path    # Long flags\nrm --force --recursive /path    # Long flags, reversed\nrm -rf --no-preserve-root /     # Additional flags\n```\n\nAll variants are handled by flexible regex patterns.\n\n### Shell Variable Expansion\n\nTemp directory variables come in multiple forms:\n\n```bash\nrm -rf $TMPDIR/build           # Unquoted, simple\nrm -rf ${TMPDIR}/build         # Unquoted, braced\nrm -rf \"$TMPDIR/build\"         # Quoted, simple\nrm -rf \"${TMPDIR}/build\"       # Quoted, braced\nrm -rf \"${TMPDIR:-/tmp}/build\" # With default value\n```\n\n### Git Flag Combinations\n\nGit commands can have flags in various positions:\n\n```bash\ngit push --force                  # Blocked ✓\ngit push origin main --force      # Blocked ✓\ngit push --force origin main      # Blocked ✓\ngit push -f                       # Blocked ✓\ngit push --force-with-lease       # Allowed ✓ (safe alternative)\n```\n\n### Staged vs Worktree Restore\n\nThe restore command has nuanced safety:\n\n```bash\ngit restore --staged file.txt           # Allowed ✓ (unstaging only)\ngit restore -S file.txt                 # Allowed ✓ (short flag)\ngit restore file.txt                    # Blocked (discards changes)\ngit restore --worktree file.txt         # Blocked (explicit worktree)\ngit restore --staged --worktree file    # Blocked (includes worktree)\ngit restore -S -W file.txt              # Blocked (includes worktree)\n```\n\n## Performance Optimizations\n\n### Dual Regex Engine Architecture\n\ndcg uses a sophisticated dual-engine regex system that automatically selects the optimal engine for each pattern. This enables both guaranteed performance and advanced pattern matching features.\n\n**The Two Engines**:\n\n| Engine | Crate | Time Complexity | Features | Use Case |\n|--------|-------|-----------------|----------|----------|\n| **Linear** | `regex` | O(n) guaranteed | Basic regex, character classes, alternation | ~85% of patterns |\n| **Backtracking** | `fancy_regex` | O(2^n) worst case | Lookahead, lookbehind, backreferences | ~15% of patterns |\n\n**Automatic Engine Selection**:\n\nWhen a pattern is compiled, dcg analyzes it to determine which engine to use:\n\n```rust\npub enum CompiledRegex {\n    Linear(regex::Regex),           // O(n) guaranteed, no lookahead\n    Backtracking(fancy_regex::Regex), // Supports lookahead/lookbehind\n}\n\nimpl CompiledRegex {\n    pub fn new(pattern: \u0026str) -\u003e Result\u003cSelf, Error\u003e {\n        // Try linear engine first (faster, predictable)\n        if let Ok(re) = regex::Regex::new(pattern) {\n            return Ok(CompiledRegex::Linear(re));\n        }\n        // Fall back to backtracking for advanced features\n        Ok(CompiledRegex::Backtracking(fancy_regex::Regex::new(pattern)?))\n    }\n}\n```\n\n**Why This Matters**:\n\n1. **Performance predictability**: The linear engine guarantees O(n) matching time, critical for a hook that runs on every command\n2. **Feature completeness**: Some patterns require negative lookahead (e.g., \"match `--force` but not `--force-with-lease`\")\n3. **Automatic optimization**: Pattern authors don't need to think about engine selection—dcg chooses optimally\n\n**Examples of Engine Selection**:\n\n```rust\n// Linear engine (simple pattern)\nr\"git\\s+reset\\s+--hard\"              // No advanced features needed\n\n// Backtracking engine (negative lookahead)\nr\"git\\s+push\\s+.*--force(?![-a-z])\"  // Must NOT be followed by \"-with-lease\"\n\n// Linear engine (character classes)\nr\"rm\\s+-[a-zA-Z]*[rR][a-zA-Z]*f\"     // Complex but no lookahead\n```\n\n### Performance Budget System\n\ndcg operates under strict latency constraints—every Bash command passes through the hook, so even small delays compound into noticeable sluggishness. The performance budget system enforces these constraints with fail-open semantics.\n\n**Latency Tiers**:\n\n| Tier | Stage | Target | Warning | Panic |\n|------|-------|--------|---------|-------|\n| 0 | Quick Reject | \u003c 1μs | \u003e 10μs | \u003e 50μs |\n| 1 | Normalization | \u003c 5μs | \u003e 25μs | \u003e 100μs |\n| 2 | Safe Pattern Check | \u003c 50μs | \u003e 200μs | \u003e 500μs |\n| 3 | Destructive Pattern Check | \u003c 50μs | \u003e 200μs | \u003e 500μs |\n| 4 | Heredoc Extraction | \u003c 1ms | \u003e 5ms | \u003e 20ms |\n| 5 | Heredoc Evaluation | \u003c 2ms | \u003e 10ms | \u003e 30ms |\n| 6 | Full Pipeline | \u003c 5ms | \u003e 15ms | \u003e 50ms |\n\n**Fail-Open Behavior**:\n\nIf any stage exceeds its panic threshold, dcg logs a warning and **allows the command**:\n\n```\n[WARN] Performance budget exceeded: Tier 2 (safe patterns) took 1.2ms (panic threshold: 500μs)\n[WARN] Failing open to avoid blocking workflow\n```\n\nThis design ensures that:\n1. A pathological input cannot hang the user's terminal\n2. Performance regressions are visible in logs\n3. The tool never becomes a productivity bottleneck\n\n**Budget Enforcement**:\n\n```rust\nfn check_budget(tier: Tier, elapsed: Duration) -\u003e BudgetResult {\n    let budget = TIER_BUDGETS[tier];\n    if elapsed \u003e budget.panic {\n        log::warn!(\"Tier {} exceeded panic threshold\", tier);\n        return BudgetResult::FailOpen;\n    }\n    if elapsed \u003e budget.warning {\n        log::warn!(\"Tier {} exceeded warning threshold\", tier);\n    }\n    BudgetResult::Continue\n}\n```\n\n**Monitoring Performance**:\n\nUse `dcg explain --verbose` to see per-stage timing:\n\n```\nEvaluation Trace:\n  [  0.3μs] Tier 0: Quick reject (PASS - below 1μs target)\n  [  1.2μs] Tier 1: Normalize (PASS - below 5μs target)\n  [  8.7μs] Tier 2: Safe patterns (PASS - below 50μs target)\n  [ 15.2μs] Tier 3: Destructive patterns (PASS - below 50μs target)\n  [ 15.4μs] Total: 15.4μs (PASS - below 5ms target)\n```\n\n### Keyword-Based Pack Pre-filtering\n\nBefore expensive regex matching, dcg uses a multi-level keyword filtering system to quickly skip irrelevant packs. This is critical for performance—with 49+ packs available, checking every pattern against every command would be prohibitively slow.\n\n**How Keyword Filtering Works**:\n\nEach pack declares a set of keywords that must appear in a command for that pack to be relevant:\n\n```rust\nPack {\n    id: \"database.postgresql\".to_string(),\n    keywords: \u0026[\"psql\", \"dropdb\", \"createdb\", \"DROP\", \"TRUNCATE\", \"DELETE\"],\n    // ...\n}\n```\n\n**Two-Level Filtering**:\n\n1. **Global Quick Reject**: Before any pack evaluation, dcg checks if the command contains *any* keyword from *any* enabled pack. If not, the entire pack evaluation is skipped.\n\n2. **Per-Pack Quick Reject**: For each enabled pack, dcg checks if the command contains any of that pack's keywords before running expensive regex patterns.\n\n**Aho-Corasick Automaton**:\n\nFor packs with multiple keywords, dcg builds an [Aho-Corasick automaton](https://en.wikipedia.org/wiki/Aho%E2%80%93Corasick_algorithm) that matches all keywords in a single O(n) pass:\n\n```rust\n// Built lazily on first pack access\npub keyword_matcher: Option\u003caho_corasick::AhoCorasick\u003e,\n\npub fn might_match(\u0026self, cmd: \u0026str) -\u003e bool {\n    if self.keywords.is_empty() {\n        return true; // No keywords = always check patterns\n    }\n\n    // O(n) matching regardless of keyword count\n    if let Some(ref ac) = self.keyword_matcher {\n        return ac.is_match(cmd);\n    }\n\n    // Fallback: sequential memchr search\n    self.keywords.iter()\n        .any(|kw| memmem::find(cmd.as_bytes(), kw.as_bytes()).is_some())\n}\n```\n\n**Context-Aware Keyword Matching**:\n\nKeywords are only matched within executable spans (not in comments, quoted strings, or data):\n\n```rust\npub fn pack_aware_quick_reject(cmd: \u0026str, enabled_keywords: \u0026[\u0026str]) -\u003e bool {\n    // First: fast substring check\n    let any_substring = enabled_keywords.iter()\n        .any(|kw| memmem::find(cmd.as_bytes(), kw.as_bytes()).is_some());\n\n    if !any_substring {\n        return true; // Safe to skip all pack evaluation\n    }\n\n    // Second: verify keyword appears in executable context\n    let spans = classify_command(cmd);\n    for span in spans.executable_spans() {\n        if span_matches_any_keyword(span.text(cmd), enabled_keywords) {\n            return false; // Must evaluate packs\n        }\n    }\n\n    true // Keywords only in non-executable contexts, safe to skip\n}\n```\n\nThis approach ensures that a command like `echo \"psql\" | grep DROP` doesn't trigger PostgreSQL pack evaluation just because keywords appear in the data being processed.\n\n### 1. Lazy Static Initialization\n\nRegex patterns are compiled once on first use via `LazyLock`:\n\n```rust\nstatic SAFE_PATTERNS: LazyLock\u003cVec\u003cPattern\u003e\u003e = LazyLock::new(|| {\n    vec![\n        pattern!(\"checkout-new-branch\", r\"git\\s+checkout\\s+-b\\s+\"),\n        // ... 33 more patterns\n    ]\n});\n```\n\nSubsequent invocations reuse the compiled patterns with zero compilation overhead.\n\n### 2. SIMD-Accelerated Quick Rejection\n\nBefore any regex matching, a SIMD-accelerated substring search filters out irrelevant commands. The [memchr](https://github.com/BurntSushi/memchr) crate uses CPU vector instructions (SSE2, AVX2, NEON) when available:\n\n```rust\nuse memchr::memmem;\n\nstatic GIT_FINDER: LazyLock\u003cmemmem::Finder\u003c'static\u003e\u003e = LazyLock::new(|| memmem::Finder::new(\"git\"));\nstatic RM_FINDER: LazyLock\u003cmemmem::Finder\u003c'static\u003e\u003e = LazyLock::new(|| memmem::Finder::new(\"rm\"));\n\nfn quick_reject(cmd: \u0026str) -\u003e bool {\n    let bytes = cmd.as_bytes();\n    GIT_FINDER.find(bytes).is_none() \u0026\u0026 RM_FINDER.find(bytes).is_none()\n}\n```\n\nFor commands like `ls -la`, `cargo build`, or `npm install`, this check short-circuits the entire matching pipeline. The `memmem::Finder` is pre-compiled once and reused, avoiding repeated setup costs.\n\n### 3. Early Exit on Safe Match\n\nSafe patterns are checked first. On match, the function returns immediately without checking destructive patterns:\n\n```rust\nfor pattern in SAFE_PATTERNS.iter() {\n    if pattern.regex.is_match(\u0026normalized).unwrap_or(false) {\n        return;  // Allow immediately\n    }\n}\n```\n\n### 4. Compile-Time Pattern Validation\n\nThe `pattern!` and `destructive!` macros include the pattern name in panic messages, making invalid patterns fail at first execution with clear diagnostics:\n\n```rust\nmacro_rules! pattern {\n    ($name:literal, $re:literal) =\u003e {\n        Pattern {\n            regex: Regex::new($re).expect(concat!(\"pattern '\", $name, \"' should compile\")),\n            name: $name,\n        }\n    };\n}\n```\n\n### 5. Zero-Copy JSON Parsing\n\nThe `serde_json` parser operates on the input buffer without unnecessary copies. The command string is extracted directly from the parsed JSON value.\n\n### 6. Zero-Allocation Path Normalization\n\nCommand normalization uses `Cow\u003cstr\u003e` (copy-on-write) to avoid heap allocations in the common case:\n\n```rust\nfn normalize_command(cmd: \u0026str) -\u003e Cow\u003c'_, str\u003e {\n    // Fast path: if command doesn't start with '/', no normalization needed\n    if !cmd.starts_with('/') {\n        return Cow::Borrowed(cmd);  // Zero allocation\n    }\n    PATH_NORMALIZER.replace(cmd, \"$1\")  // Allocation only when path is stripped\n}\n```\n\nMost commands don't use absolute paths to `git` or `rm`, so this fast path avoids allocation entirely for 99%+ of inputs.\n\n### 7. Release Profile Optimization\n\nThe release build uses aggressive optimization settings:\n\n```toml\n[profile.release]\nopt-level = \"z\"     # Optimize for size (lean binary)\nlto = true          # Link-time optimization across crates\ncodegen-units = 1   # Single codegen unit for better optimization\npanic = \"abort\"     # Smaller binary, no unwinding overhead\nstrip = true        # Remove debug symbols\n```\n\n## Example Block Message\n\nWhen a destructive command is intercepted, the hook outputs a colorful warning to stderr (shown below without ANSI codes):\n\n```\n════════════════════════════════════════════════════════════════════════\nBLOCKED  dcg\n────────────────────────────────────────────────────────────────────────\nReason:  git reset --hard destroys uncommitted changes. Use 'git stash' first.\n\nCommand:  git reset --hard HEAD~1\n\nTip: If you need to run this command, execute it manually in a terminal.\n     Consider using 'git stash' first to save your changes.\n════════════════════════════════════════════════════════════════════════\n```\n\n### Suggestion System\n\ndcg doesn't just block commands—it provides actionable guidance to help users make safer choices. The suggestion system generates context-aware recommendations based on the specific command that was blocked.\n\n**Suggestion Categories**:\n\n| Category | Purpose | Example |\n|----------|---------|---------|\n| `PreviewFirst` | Run a dry-run/preview command first | \"Run `git clean -n` first to preview deletions\" |\n| `SaferAlternative` | Use a safer command that achieves similar goals | \"Use `--force-with-lease` instead of `--force`\" |\n| `WorkflowFix` | Fix the workflow to avoid the dangerous operation | \"Commit your changes before resetting\" |\n| `Documentation` | Link to relevant documentation | \"See `man git-reset` for reset options\" |\n| `AllowSafely` | How to allowlist if the operation is intentional | \"Add to allowlist: `dcg allowlist add core.git:reset-hard`\" |\n\n**Contextual Suggestions by Command Type**:\n\n| Command Type | Suggestion |\n|-------------|------------|\n| `git reset`, `git checkout --` | \"Consider using 'git stash' first to save your changes.\" |\n| `git clean` | \"Use 'git clean -n' first to preview what would be deleted.\" |\n| `git push --force` | \"Consider using '--force-with-lease' for safer force pushing.\" |\n| `rm -rf` | \"Verify the path carefully before running rm -rf manually.\" |\n| `kubectl delete` | \"Use `kubectl delete --dry-run=client` to preview deletions.\" |\n| `docker system prune` | \"Run with `--dry-run` first to see what would be removed.\" |\n| `DROP TABLE` | \"Consider `TRUNCATE` if you only need to remove data, not the schema.\" |\n\n**Custom Suggestions in Packs**:\n\nEach destructive pattern can specify its own suggestion tailored to the specific operation:\n\n```rust\ndestructive_pattern!(\n    \"restic-forget\",\n    r\"restic(?:\\s+--?\\S+(?:\\s+\\S+)?)*\\s+forget\\b\",\n    \"restic forget removes snapshots and can permanently delete backup data.\",\n    suggestion: \"Run 'restic snapshots' first to review what would be affected.\"\n)\n```\n\nThis approach ensures that suggestions are always relevant to the specific context, not generic warnings.\n\nSimultaneously, the hook outputs JSON to stdout for the Claude Code protocol:\n\n```json\n{\n  \"hookSpecificOutput\": {\n    \"hookEventName\": \"PreToolUse\",\n    \"permissionDecision\": \"deny\",\n    \"permissionDecisionReason\": \"BLOCKED by dcg\\n\\nReason: ...\"\n  }\n}\n```\n\n## Security Considerations\n\n### What This Protects Against\n\n- **Accidental data loss**: AI agents running `git checkout --` or `git reset --hard` on files with uncommitted changes\n- **Remote history destruction**: Force pushes that overwrite shared branch history\n- **Stash loss**: Dropping or clearing stashes containing important work-in-progress\n- **Filesystem accidents**: Recursive deletion outside designated temp directories\n\n### Inherent Limitations\n\nWhile dcg provides comprehensive protection across many tools and platforms, some attack vectors are inherently difficult or impossible to protect against:\n- **Malicious actors**: A determined attacker can bypass this hook\n- **Non-Bash commands**: Direct file writes via Python/JavaScript, API calls, etc. are not intercepted\n- **Committed but unpushed work**: The hook doesn't prevent loss of local-only commits\n- **Bugs in allowed commands**: A `git commit` that accidentally includes wrong files\n- **Commands in scripts**: If an agent runs `./deploy.sh`, we don't inspect what's inside the script\n\n### Threat Model\n\nThis hook assumes the AI agent is **well-intentioned but fallible**. It's designed to catch honest mistakes, not adversarial attacks. The hook runs with the same permissions as the Claude Code process.\n\n## Troubleshooting\n\n### Hook not blocking commands\n\n1. **Check hook registration**: Verify `~/.claude/settings.json` contains the hook configuration\n2. **Restart Claude Code**: Configuration changes require a restart\n3. **Check binary location**: Ensure `dcg` is in your PATH\n4. **Test manually**: Run `echo '{\"tool_name\":\"Bash\",\"tool_input\":{\"command\":\"git reset --hard\"}}' | dcg`\n\n### Hook silently removed (recommended: add shell startup check)\n\nClaude Code can silently remove the dcg hook when it rewrites `~/.claude/settings.json`. This means you may lose protection without any warning.\n\n**Automatic setup** -- `dcg setup` installs the hook *and* offers to add a shell startup check:\n\n```bash\ndcg setup               # Interactive — prompts before modifying RC files\ndcg setup --shell-check # Non-interactive — adds the check automatically\n```\n\n**Manual setup** -- add this snippet to your `~/.zshrc` and/or `~/.bashrc`:\n\n```bash\n# dcg: warn if hook was silently removed from Claude Code settings\nif command -v dcg \u0026\u003e/dev/null \u0026\u0026 command -v jq \u0026\u003e/dev/null; then\n  if [ -f \"$HOME/.claude/settings.json\" ] \u0026\u0026 \\\n     ! jq -e '.hooks.PreToolUse[]? | select(.hooks[]?.command | test(\"dcg$\"))' \\\n       \"$HOME/.claude/settings.json\" \u0026\u003e/dev/null; then\n    printf '\\033[1;33m[dcg] Hook missing from ~/.claude/settings.json — run: dcg install\\033[0m\\n'\n  fi\nfi\n```\n\nThis check:\n- Runs in milliseconds (no noticeable shell startup delay)\n- Is completely silent when the hook is present\n- Shows a yellow warning only when the hook is missing\n- Gracefully skips if `dcg`, `jq`, or `settings.json` are absent\n- Works identically in bash and zsh\n\n\u003e **Note:** The `install.sh` installer also offers to add this check during installation.\n\n### Hook blocking safe commands\n\n1. **Check for false positives**: Some edge cases may not be covered by safe patterns\n2. **File an issue**: Report the command that was incorrectly blocked\n3. **Temporary bypass**: Have the user run the command manually in a separate terminal\n4. **Add to allowlist**: Use the allowlist feature below for persistent overrides\n\n### Resolving False Positives with Allowlists\n\nIf dcg blocks a command that is safe in your specific context, you can add it to an allowlist. Allowlists support three layers (checked in order):\n\n1. **Project** (`.dcg/allowlist.toml`): Applies only to the current project\n2. **User** (`~/.config/dcg/allowlist.toml`): Applies to all your projects\n3. **System** (`/etc/dcg/allowlist.toml`): Applies system-wide\n\n**Adding a rule to the allowlist:**\n\n```bash\n# Allow a specific rule by ID (recommended)\ndcg allowlist add core.git:reset-hard -r \"Used for CI cleanup\"\n\n# Allow at project level (default if in a git repo)\ndcg allowlist add core.git:reset-hard -r \"CI cleanup\" --project\n\n# Add to user-level allowlist instead\ndcg allowlist add core.git:reset-hard -r \"Personal workflow\" --user\n\n# Allow with expiration (ISO 8601 format)\ndcg allowlist add core.git:clean-force -r \"Migration\" --expires \"2026-02-01T00:00:00Z\"\n\n# Allow a specific command (exact match) using add-command\ndcg allowlist add-command \"rm -rf ./build\" -r \"Build cleanup\"\n```\n\n**Listing allowlist entries:**\n\n```bash\n# List all entries from all layers\ndcg allowlist list\n\n# List project allowlist only\ndcg allowlist list --project\n\n# List user allowlist only\ndcg allowlist list --user\n\n# Output as JSON\ndcg allowlist list --format json\n```\n\n**Removing entries:**\n\n```bash\n# Remove a rule by ID\ndcg allowlist remove core.git:reset-hard\n\n# Remove from project allowlist specifically\ndcg allowlist remove core.git:reset-hard --project\n```\n\n**Validating allowlist files:**\n\n```bash\n# Check for issues (expired entries, invalid patterns)\ndcg allowlist validate\n\n# Strict mode: treat warnings as errors\ndcg allowlist validate --strict\n```\n\n**Example allowlist.toml:**\n\n```toml\n[[allow]]\nrule = \"core.git:reset-hard\"\nreason = \"Used for CI pipeline cleanup\"\nadded_at = \"2026-01-08T12:00:00Z\"\n\n[[allow]]\nexact_command = \"rm -rf ./build\"\nreason = \"Safe build directory cleanup\"\nadded_at = \"2026-01-08T12:00:00Z\"\nexpires_at = \"2026-02-08T12:00:00Z\"  # Optional expiration\n\n[[allow]]\npattern = \"rm -rf .*/build\"\nreason = \"Build directories across projects\"\nrisk_acknowledged = true  # Required for pattern-based entries\nadded_at = \"2026-01-08T12:00:00Z\"\n```\n\n### Performance issues\n\n1. **Check pattern count**: Excessive custom patterns can slow matching\n2. **Profile with `--release`**: Debug builds are significantly slower\n3. **Check stdin buffering**: Slow JSON input can delay processing\n\n## Running Tests\n\n### Unit Tests\n\n```bash\ncargo test\n```\n\nThe test suite includes 80+ tests covering:\n\n- **normalize_command_tests**: Path stripping for git and rm binaries\n- **quick_reject_tests**: Fast-path filtering for non-git/rm commands\n- **safe_pattern_tests**: Whitelist accuracy for all safe pattern variants\n- **destructive_pattern_tests**: Blacklist coverage for all dangerous commands\n- **input_parsing_tests**: JSON parsing robustness and edge cases\n- **deny_output_tests**: Output format validation\n- **integration_tests**: End-to-end pipeline verification\n\n### Test with Coverage\n\n```bash\ncargo install cargo-tarpaulin\ncargo tarpaulin --out Html\n```\n\n### End-to-End Testing\n\nThe repository includes a comprehensive E2E test script with 120 test cases:\n\n```bash\n# Run full E2E test suite\n./scripts/e2e_test.sh\n\n# With verbose output\n./scripts/e2e_test.sh --verbose\n\n# With specific binary path\n./scripts/e2e_test.sh --binary ./target/release/dcg\n```\n\nThe E2E suite covers:\n- All destructive git commands (reset, checkout, restore, clean, push, branch, stash)\n- All safe git commands (status, log, diff, add, commit, push, branch -d)\n- Filesystem commands (rm -rf with various paths and flag orderings)\n- Absolute path handling (`/usr/bin/git`, `/bin/rm`)\n- Non-Bash tools (Read, Write, Edit, Grep, Glob)\n- Malformed JSON input (empty, missing fields, invalid syntax)\n- Edge cases (sudo prefixes, quoted paths, variable expansion)\n\n## Continuous Integration\n\nThe project uses GitHub Actions for CI/CD:\n\n### CI Workflow (`.github/workflows/ci.yml`)\n\nRuns on every push and pull request:\n\n- **Formatting check**: `cargo fmt --check`\n- **Clippy lints**: `cargo clippy --all-targets -- -D warnings` (pedantic + nursery enabled)\n- **Compilation check**: `cargo check --all-targets`\n- **Unit tests**: `cargo nextest run` with JUnit XML reports\n- **Coverage**: `cargo llvm-cov` with LCOV output\n\n### Release Workflow (`.github/workflows/dist.yml`)\n\nTriggered on version tags (`v*`):\n\n- Builds optimized binaries for 5 platforms:\n  - Linux x86_64 (`x86_64-unknown-linux-gnu`)\n  - Linux ARM64 (`aarch64-unknown-linux-gnu`)\n  - macOS Intel (`x86_64-apple-darwin`)\n  - macOS Apple Silicon (`aarch64-apple-darwin`)\n  - Windows (`x86_64-pc-windows-msvc`)\n- Creates `.tar.xz` archives (Unix) or `.zip` (Windows)\n- Generates SHA256 checksums for verification\n- Publishes to GitHub Releases with auto-generated release notes\n\nTo create a release:\n\n```bash\ngit tag v0.1.0\ngit push origin v0.1.0\n```\n\n## FAQ\n\n**Q: Why block `git branch -D` but allow `git branch -d`?**\n\nThe lowercase `-d` only deletes branches that have been fully merged. The uppercase `-D` force-deletes regardless of merge status, potentially losing commits that exist only on that branch.\n\n**Q: Why is `git push --force-with-lease` allowed?**\n\nForce-with-lease is a safer alternative that refuses to push if the remote has commits you haven't seen. It prevents accidentally overwriting someone else's work.\n\n**Q: Why block all `rm -rf` outside temp directories?**\n\nRecursive forced deletion is one of the most dangerous filesystem operations. Even with good intentions, a typo or wrong variable expansion can delete critical files. Temp directories are designed to be ephemeral.\n\n**Q: Can I add custom patterns?**\n\nCurrently, patterns are compiled into the binary. For custom patterns, fork the repository and modify `SAFE_PATTERNS` or `DESTRUCTIVE_PATTERNS` in `src/main.rs`.\n\n**Q: What if I really need to run a blocked command?**\n\nThe block message instructs the AI to ask you for explicit permission. You can then run the command manually in a separate terminal, ensuring you've made a conscious decision.\n\n**Q: Does this work with other AI coding tools?**\n\nYes. dcg natively supports Claude Code, Gemini CLI, and GitHub Copilot CLI hook payloads. For other tools, support depends on whether they expose a pre-execution shell hook with compatible JSON input/output.\n\n**Q: What about database, Docker, Kubernetes, and cloud commands?**\n\ndcg already includes comprehensive packs for all of these! The modular pack system covers databases (PostgreSQL, MySQL, MongoDB, Redis, SQLite), containers (Docker, Podman, docker-compose), Kubernetes (kubectl, Helm, Kustomize), and all major cloud providers (AWS, GCP, Azure) including their container registries, secrets management services, and logging infrastructure. Enable the packs you need in your config. If you encounter a destructive command that should be blocked, please file an issue.\n\n## Contributing\n\n*About Contributions:* Please don't take this the wrong way, but I do not accept outside contributions for any of my projects. I simply don't have the mental bandwidth to review anything, and it's my name on the thing, so I'm responsible for any problems it causes; thus, the risk-reward is highly asymmetric from my perspective. I'd also have to worry about other \"stakeholders,\" which seems unwise for tools I mostly make for myself for free. Feel free to submit issues, and even PRs if you want to illustrate a proposed fix, but know I won't merge them directly. Instead, I'll have Claude or Codex review submissions via `gh` and independently decide whether and how to address them. Bug reports in particular are welcome. Sorry if this offends, but I want to avoid wasted time and hurt feelings. I understand this isn't in sync with the prevailing open-source ethos that seeks community contributions, but it's the only way I can move at this velocity and keep my sanity.\n\n## License\n\nMIT\n","funding_links":[],"categories":["Rust"],"sub_categories":[],"project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2FDicklesworthstone%2Fdestructive_command_guard","html_url":"https://awesome.ecosyste.ms/projects/github.com%2FDicklesworthstone%2Fdestructive_command_guard","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2FDicklesworthstone%2Fdestructive_command_guard/lists"}