dcg (Destructive Command Guard)
A high-performance hook for AI coding agents that blocks destructive commands before they execute, protecting your work from accidental deletion across Claude Code, Codex CLI, Gemini CLI, Copilot CLI, VS Code Copilot Chat, Cursor, Hermes Agent, Grok (xAI), Posit Assistant, Oh My Pi, and related tools.
Supported: Claude Code, Codex CLI 0.125.0+, Gemini CLI, GitHub Copilot CLI, VS Code Copilot Chat, Cursor IDE, Hermes Agent, Posit Assistant (Positron/RStudio extension, standalone server, and pa terminal client), Grok (xAI) (native ~/.grok/hooks/ plus Claude compatibility layer), Antigravity CLI (agy) (native ~/.gemini/config/hooks.json via dcg install --agy), OpenCode (native tool.execute.before plugin via dcg install --opencode — see docs/opencode-integration.md), Oh My Pi (omp) (native tool_call extension via dcg install --omp), Crush (native hooks.PreToolUse entry in crush.json via dcg install --crush — see docs/crush-integration.md), Reasonix (native hooks.PreToolUse entry in settings.json via dcg install --reasonix — see docs/reasonix-integration.md), Pi (via extension recipe), Aider (limited—git hooks only), Continue (detection only)
Quick Install
curl -fsSL "https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.sh?$(date +%s)" | bash -s -- --easy-modeWorks on Linux, macOS, and Windows via WSL. Auto-detects your platform, downloads the right binary, and configures supported agent hooks including Claude Code, Codex CLI, Gemini CLI, GitHub Copilot CLI, VS Code Copilot Chat (through VS Code's Claude-hook compatibility), Cursor IDE, Hermes Agent, Posit Assistant, Oh My Pi, and Grok (xAI) (via dcg install --grok for a native ~/.grok/hooks/dcg.json, or via the Claude compatibility layer automatically picked up by Grok). For native Windows, use the PowerShell installer below.
Windows (native, PowerShell)
& ([scriptblock]::Create((irm "https://raw.githubusercontent.com/Dicklesworthstone/destructive_command_guard/main/install.ps1"))) -EasyMode -VerifyInstalls native dcg.exe, verifies the mandatory SHA256 checksum, verifies the release's long-lived minisign signature when minisign is available, and verifies Sigstore/cosign provenance when both cosign and a trusted bundle are available. It adds dcg to your User PATH (-EasyMode), runs a self-test (-Verify), and configures detected agent hooks for Claude Code, Codex CLI, Gemini CLI, GitHub Copilot CLI, Cursor IDE, Hermes Agent, Posit Assistant, and Oh My Pi. Copilot is configured at the user level under %COPILOT_HOME%\hooks (or %USERPROFILE%\.copilot\hooks) so every workspace is protected. On Windows the windows.filesystem and windows.system packs are on by default, so del /s, rd /s, Remove-Item -Recurse (with or without -Force), format, and vssadmin delete shadows are blocked out of the box. Pin a version with -Version vX.Y.Z; use -RequireMinisign to fail closed if the sidecar or verifier is unavailable.
TL;DR
The Problem: AI coding agents (Claude, Codex, Gemini, Copilot, etc.) occasionally run catastrophic commands like git reset --hard, rm -rf ./src, or DROP TABLE users—destroying hours of uncommitted work in seconds.
The Solution: dcg is a high-performance hook that intercepts destructive commands before they execute, blocking them with clear explanations and safer alternatives.
Why Use dcg?
| Feature | What It Does |
|---|---|
| Zero-Config Protection | Blocks dangerous git/filesystem commands out of the box |
| 50+ Security Packs | Databases, Kubernetes, Docker, AWS/GCP/Azure, Terraform, and more |
| Sub-Millisecond Latency | SIMD-accelerated filtering—you won't notice it's there |
| Heredoc/Inline Script Scanning | Catches python -c "os.remove(...)" and embedded shell scripts |
| Smart Context Detection | Won't block grep "rm -rf" (data) but will block rm -rf / (execution) |
| Rich Terminal Output | Human-readable denial panels, rule context, and suggestions on stderr |
| Agent-Safe Streams | Machine-readable hook output stays on stdout while rich UI stays on stderr |
| Native Codex Support | Codex CLI 0.125.0+ receives a minimal stdout JSON denial that current clients enforce reliably |
| Graceful Degradation | Plain output for CI, pipes, dumb terminals, and no-color environments |
| Scan Mode for CI | Pre-commit hooks and CI integration to catch dangerous commands in code review |
| Bounded Failure Policy | Analysis timeouts become explicit review/block outcomes; malformed raw hook envelopes remain auditable and configurable |
| Explain Mode | dcg explain "command" shows exactly why something is blocked |
Quick Example
# AI agent tries to run:
$ git reset --hard HEAD~5
# dcg intercepts and blocks:
════════════════════════════════════════════════════════════════
BLOCKED dcg
────────────────────────────────────────────────────────────────
Reason: git reset --hard destroys uncommitted changes
Command: git reset --hard HEAD~5
Tip: Consider using 'git stash' first to save your changes.
════════════════════════════════════════════════════════════════Enable More Protection
# ~/.config/dcg/config.toml
[packs]
enabled = [
"database.postgresql", # Blocks DROP TABLE, TRUNCATE
"kubernetes.kubectl", # Blocks kubectl delete namespace
"cloud.aws", # Blocks aws ec2 terminate-instances
"containers.docker", # Blocks docker system prune
]Agent-Specific Profiles
dcg automatically detects which AI coding agent is invoking it and can apply
agent-specific configuration. The trust_level field is an advisory label
recorded in JSON output and logs — it does not directly change rule evaluation.
Behavioral differences come from the other profile fields:
| Option | Effect |
|---|---|
disabled_packs |
Removes rule packs from evaluation |
extra_packs |
Adds rule packs to evaluation |
additional_allowlist |
Adds command patterns that bypass deny rules |
disabled_allowlist |
When true, ignores all allowlist entries |
# Trust Claude Code more — wider allowlist, fewer packs
[agents.claude-code]
trust_level = "high"
additional_allowlist = ["npm run build", "cargo test"]
disabled_packs = ["kubernetes"]
# Oh My Pi has its own canonical profile (distinct from legacy Pi)
[agents.omp]
trust_level = "medium"
extra_packs = ["strict_git"]
# Restrict unknown agents — extra rules, no allowlist bypass
[agents.unknown]
trust_level = "low"
extra_packs = ["strict_git", "database"] # real pack / category IDs (see `dcg packs`)
disabled_allowlist = true
extra_packs/disabled_packstake the same pack and category IDs as[packs] enabled/disabled— a category ID like"database"expands to everydatabase.*sub-pack. Use IDs listed bydcg packsor indocs/packs/README.md;"paranoid"is a graduation mode, not a pack, so enable the realstrict_gitpack for stricter git rules.
See docs/agents.md for full documentation on supported agents, trust levels, and configuration options.
Codex Support
dcg now treats Codex CLI as a first-class hook target, not just a Claude-shaped
compatibility path. The installer configures Codex CLI 0.125.0+ automatically
when it detects codex on PATH or an existing ~/.codex/ directory.
| Codex behavior | dcg handling |
|---|---|
| Hook config | Merges a PreToolUse Bash hook into ~/.codex/hooks.json |
| Denied command | Exits 0 with a minimal hookSpecificOutput denial on stdout; human warning stays on stderr |
| Allowed command | Exits 0 with empty stdout and stderr |
| Existing hooks | Preserves coexisting hooks, keeps dcg first for Bash, and refuses to overwrite malformed JSON |
| Validation | Covered by subprocess protocol tests plus an opt-in real Codex E2E harness |
Codex's hook input is intentionally close to Claude Code's, but Codex rejects
unknown fields in hook output. dcg detects Codex payloads from the non-empty
turn_id field and emits only Codex's documented denial fields so a blocked
command is reported as blocked rather than as a failed hook. See
docs/codex-integration.md for protocol details,
manual probes, and troubleshooting.
Origins & Authors
This 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.
- Jeffrey Emanuel - Original concept and Python implementation (source); substantially expanded the Rust version with the modular pack system (50+ security packs), heredoc/inline-script scanning, the three-tier architecture, context classification, allowlists, scan mode, and the dual regex engine
- Darin Gordon - Initial Rust port with performance optimizations
The 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.
Escape Hatch / Bypass
If dcg is blocking something you genuinely need to run:
| Method | Scope | How |
|---|---|---|
| Env var bypass | Single command | DCG_BYPASS=1 <command> |
| Allow-once code | Single command | Copy the short code from the block message, run dcg allow-once <code> |
| Permanent allowlist | Rule or command | dcg allowlist add core.git:reset-hard -r "reason" |
| Remove the hook | All commands | Delete or comment out the dcg entry in ~/.claude/settings.json (or equivalent for your agent) |
DCG_BYPASS=1 disables all protection for that invocation. Use it sparingly and prefer allowlists for recurring needs.
Modular Pack System
dcg uses a modular "pack" system to organize destructive command patterns by category. Packs can be enabled or disabled in the configuration file.
Category IDs expand to their sub-packs. Listing a bare category in enabled
turns on every pack under it: enabled = ["database"] activates
database.postgresql, database.mysql, and the rest of that category. You can
still drop a single sub-pack with disabled = ["database.redis"]. The same
expansion applies to agent-profile extra_packs / disabled_packs. Always use
real pack or category IDs from dcg packs / docs/packs/README.md — a name like
"paranoid" is a graduation mode, not a pack.
- Full pack ID index:
docs/packs/README.md - Canonical descriptions + pattern counts:
dcg packs --verbose
Enabled by default (no config file)
With no config file present, dcg enables only the packs that guard against the most catastrophic, unrecoverable mistakes:
core.filesystem- Dangerous recursivermoperations and equivalent filesystem destruction outside literal temp subdirectories (always enabled; cannot be removed from evaluation)core.git- Destructive git commands that lose uncommitted work, rewrite history, or destroy stashes (always enabled; cannot be removed from evaluation)system.disk-mkfs,dd-to-device,fdisk,parted,mdadm,lvmremoval,wipefs(on by default; opt out withdisabled = ["system.disk"])
"Cannot be removed" is not the same as "cannot be relaxed." A core.* pack
always evaluates, so disabled = ["core.filesystem"] is ignored — but what
dcg does with a match is policy, and policy is yours.
Relaxing a critical rule takes a per-rule entry. A broad warn or log —
whether written as [policy.packs] or as [policy] default_mode — is silently
raised back to deny for any rule whose severity is critical, and dcg does
not report that it ignored the setting. Most of what core.filesystem and
core.git exist to stop is exactly that severity, so the broad form alone will
not do what it looks like it does:
# Relaxes only the high/medium rules. `rm -rf ~/work` still hard-denies,
# because core.filesystem:rm-rf-root-home is critical.
[policy.packs]
"core.filesystem" = "warn"
# Relaxes that one critical rule. This is the form that actually works.
[policy.rules]
"core.filesystem:rm-rf-root-home" = "warn"warn lets the command run and records the decision; log does the same
silently; ask requests operator review where the hook protocol supports it.
Use dcg explain --format json '<command>' and read mode to confirm which
mode a rule actually resolved to before relying on it. See
Configuration for the constraint and
Graduated Response for the severity ladder.
On Windows, two additional packs are on by default so a fresh install blocks the catastrophic native-Windows operations with no config:
windows.filesystem- cmddel /s,rd /s,format <drive>:and PowerShellRemove-Item -Recurse(with or without-Force; aliases included),Clear-Content,Clear-RecycleBin(default-on on Windows only; opt out withdisabled = ["windows.filesystem"]or["windows"])windows.system-vssadmin delete shadows/wmic shadowcopy delete(Volume Shadow Copy destruction),diskpart,Format-Volume,Clear-Disk,Remove-Partition,cipher /w,bcdedit /delete(default-on on Windows only; opt out withdisabled = ["windows.system"]or["windows"])
The broader windows.misc (reg delete, net user /delete, wsl --unregister, robocopy /MIR) and
windows.powershell (registry/provider deletes, Remove-LocalUser, Disable-ComputerRestore, Remove-VM)
packs are opt-in on every platform. On Unix the windows.* packs are registered but off by default; enable
them (e.g. to scan committed .ps1/.cmd scripts in CI) via [packs] enabled = ["windows"].
Every other pack — including database.postgresql and containers.docker — is
opt-in and is not active until a config file enables it. Running dcg init
writes a starter ~/.config/dcg/config.toml whose [packs] enabled list turns on
database.postgresql and containers.docker as common examples, but that is a
generated starter config, not the no-config default. Enable any pack below by adding
it to [packs] enabled — see Enable More Protection.
Storage Packs
storage.s3- Protects against destructive S3 operations like bucket removal, recursive deletes, and sync --delete.storage.gcs- Protects against destructive GCS operations like bucket removal, object deletion, and recursive deletes.storage.minio- Protects against destructive MinIO Client (mc) operations like bucket removal, object deletion, and admin operations.storage.azure_blob- Protects against destructive Azure Blob Storage operations like container deletion, blob deletion, and azcopy remove.
Remote Packs
remote.rsync- Protects against destructive rsync operations like --delete and its variants.remote.scp- Protects against destructive SCP operations like overwrites to system paths.remote.ssh- Protects against destructive SSH operations like remote command execution and key management.
Database Packs
database.postgresql- Protects against destructive PostgreSQL operations like DROP DATABASE, TRUNCATE, and dropdb.database.mysql- MySQL/MariaDB guard.database.mongodb- Protects against destructive MongoDB operations like dropDatabase, dropCollection, and remove without criteria.database.redis- Protects against destructive Redis operations like FLUSHALL, FLUSHDB, and mass key deletion.database.sqlite- Protects against destructive SQLite operations like DROP TABLE, DELETE without WHERE, and accidental data loss.database.snowflake- Protects modernsnow sqlinline queries, files, stdin, nested sources, destructive data operations, pipelines, warehouses, and account privileges.database.supabase- Protects against destructive Supabase CLI operations including database resets, migration rollbacks, function/secret/storage deletion, project removal, and infrastructure changes.database.databricks- Protects against destructive Databricks CLI operations like account workspace deletion, bundle destroy, recursive workspace/fs deletion, permanent cluster deletion, secret-scope removal, and arbitrary REST DELETE calls.database.bigquery- Protects thebqCLI and GoogleSQL against dataset drops (DROP SCHEMA), table overwrites, unfiltered DML (WHERE TRUEis GoogleSQL's full-table idiom), and settings that shorten the time-travel recovery window.
Container Packs
containers.docker- Protects against destructive Docker operations like system prune, volume prune, and force removal.containers.compose- Protects against destructive Docker Compose operations like down -v which removes volumes.containers.podman- Protects against destructive Podman operations like system prune, volume prune, and force removal.
Kubernetes Packs
kubernetes.kubectl- Protects against destructive kubectl operations like delete namespace, drain, and mass deletion.kubernetes.helm- Protects against destructive Helm operations like uninstall and rollback without dry-run.kubernetes.kustomize- Protects against destructive Kustomize operations when combined with kubectl delete or applied without review.
Cloud Provider Packs
cloud.aws- Protects against destructive AWS CLI operations like terminate-instances, delete-db-instance, and s3 rm --recursive.cloud.azure- Protects against destructive Azure CLI operations like vm delete, storage account delete, and resource group delete.cloud.gcp- Protects against destructive gcloud operations like instances delete, sql instances delete, and gsutil rm -r.
CDN Packs
cdn.cloudflare_workers- Protects against destructive Cloudflare Workers, KV, R2, and D1 operations via the Wrangler CLI.cdn.cloudfront- Protects against destructive AWS CloudFront operations like deleting distributions, cache policies, and functions.cdn.fastly- Protects against destructive Fastly CLI operations like service, domain, backend, and VCL deletion.
API Gateway Packs
apigateway.apigee- Protects against destructive Google Apigee CLI and apigeecli operations.apigateway.aws- Protects against destructive AWS API Gateway CLI operations for both REST APIs and HTTP APIs.apigateway.kong- Protects against destructive Kong Gateway CLI, deck CLI, and Admin API operations.
Infrastructure Packs
infrastructure.ansible- Protects against destructive Ansible operations like dangerous shell commands and unchecked playbook runs.infrastructure.atmos- Protects against destructive Atmos operations like terraform deploy (auto-approve), clean, destroy, state rm/taint, and helmfile destroy.infrastructure.pulumi- Protects against destructive Pulumi operations like destroy and up with -y (auto-approve).infrastructure.terraform- Protects against destructive Terraform operations like destroy, taint, and apply with -auto-approve.
System Packs
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).system.permissions- Protects against dangerous permission changes like chmod 777, recursive chmod/chown on system directories.system.services- Protects against dangerous service operations like stopping critical services and modifying init configuration.
CI/CD Packs
cicd.circleci- Protects against destructive CircleCI operations like deleting contexts, removing secrets, deleting orbs/namespaces, or removing pipelines.cicd.github_actions- Protects against destructive GitHub Actions operations like deleting secrets/variables or using gh api DELETE against /actions endpoints.cicd.gitlab_ci- Protects against destructive GitLab CI/CD operations like deleting variables, removing artifacts, and unregistering runners.cicd.jenkins- Protects against destructive Jenkins CLI/API operations like deleting jobs, nodes, credentials, or build history.
Secrets Management Packs
secrets.aws_secrets- Protects against destructive AWS Secrets Manager and SSM Parameter Store operations like delete-secret and delete-parameter.secret_disclosure- Exact opt-in protection against secret-manager commands that expose credential values through agent-visible output or agent-chosen files; injection commands such asinfisical run,op run, anddoppler runremain allowed. It is intentionally outside thesecrets.*category so existingenabled = ["secrets"]configurations do not change policy on upgrade.secrets.doppler- Protects against destructive Doppler CLI operations like deleting secrets, configs, environments, or projects.secrets.infisical- Protects against deleting Infisical secrets, folders, and dynamic-secret leases, plus resetting local Infisical configuration.secrets.onepassword- Protects against destructive 1Password CLI operations like deleting items, documents, users, groups, and vaults.secrets.vault- Protects against destructive Vault CLI operations like deleting secrets, disabling auth/secret engines, revoking leases/tokens, and deleting policies.
Provider packs preserve dcg's default destructive-operation scope: read commands remain allowed. Teams that also treat transcript disclosure as destructive can enable the separate policy explicitly:
[packs]
enabled = ["secrets.infisical", "secret_disclosure"]With secret_disclosure enabled, value-emitting reads such as infisical secrets get, infisical export, op read, doppler secrets download, vault kv get, aws secretsmanager get-secret-value, aws secretsmanager batch-get-secret-value, and decrypted SSM reads are blocked. Metadata
inspection, CLI help, and direct process injection remain available.
The opt-in careful_company_running_windows preset also includes both new packs
as deliberate members of its pinned secret-store policy.
Platform Packs
platform.azure_devops- Protects against destructiveazure-devopsAzure CLI extension operations acrossaz devops,az repos,az pipelinesandaz boards: deleting team projects, repositories, refs, branch policies, pipelines, variable groups, wikis, teams, service connections and work items, removing users and group memberships, resetting permission ACLs, and issuing arbitrary state-changingaz devops invokeREST calls.az artifactsexposes no destructive command and carries no rule. Read-only verbs and ordinary development flow are untouched.platform.github- Protects against destructive GitHub CLI operations like changing repository visibility or deleting repositories, gists, releases, or SSH keys.platform.gitlab- Protects against destructive GitLab platform operations like deleting projects, releases, protected branches, and webhooks.platform.kamal- Protects against destructive Kamal 2.x operations that tear down the stack (kamal remove), delete accessory data directories (kamal accessory remove), drop proxy routing, take the app offline, or prune the images thatkamal rollbackrelies on.platform.modal- Protects against destructive Modal serverless platform operations like recursive volume removal, app stops with--force, and secret deletion.platform.railway- Protects against destructive Railway CLI and Public API operations that can delete projects, environments, services, functions, volumes, variables, or deployments.
DNS Packs
dns.cloudflare- Protects against destructive Cloudflare DNS operations like record deletion, zone deletion, and targeted Terraform destroy.dns.generic- Protects against destructive or risky DNS tooling usage (nsupdate deletes, zone transfers).dns.route53- Protects against destructive AWS Route53 DNS operations like hosted zone deletion and record set DELETE changes.
Email Packs
email.mailgun- Protects against destructive Mailgun API operations like domain deletion, route deletion, and mailing list removal.email.postmark- Protects against destructive Postmark API operations like server deletion, template deletion, and sender signature removal.email.sendgrid- Protects against destructive SendGrid API operations like template deletion, API key deletion, and domain authentication removal.email.ses- Protects against destructive AWS Simple Email Service operations like identity deletion, template deletion, and configuration set removal.
Feature Flag Packs
featureflags.flipt- Protects against destructive Flipt CLI and API operations.featureflags.launchdarkly- Protects against destructive LaunchDarkly CLI and API operations.featureflags.split- Protects against destructive Split.io CLI and API operations.featureflags.unleash- Protects against destructive Unleash CLI and API operations.
Load Balancer Packs
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.loadbalancer.haproxy- Protects against destructive HAProxy load balancer operations like stopping the service or disabling backends via runtime API.loadbalancer.nginx- Protects against destructive nginx load balancer operations like stopping the service or deleting config files.loadbalancer.traefik- Protects against destructive Traefik load balancer operations like stopping containers, deleting config, or API deletions.
Messaging Packs
messaging.kafka- Protects against destructive Kafka CLI operations like deleting topics, removing consumer groups, resetting offsets, and deleting records.messaging.nats- Protects against destructive NATS/JetStream operations like deleting streams, consumers, key-value entries, objects, and accounts.messaging.rabbitmq- Protects against destructive RabbitMQ operations like deleting queues/exchanges, purging queues, deleting vhosts, and resetting cluster state.messaging.sqs_sns- Protects against destructive AWS SQS and SNS operations like deleting queues, purging messages, deleting topics, and removing subscriptions.
Monitoring Packs
monitoring.datadog- Protects against destructive Datadog CLI/API operations like deleting monitors and dashboards.monitoring.newrelic- Protects against destructive New Relic CLI/API operations like deleting entities or alerting resources.monitoring.pagerduty- Protects against destructive PagerDuty CLI/API operations like deleting services and schedules (which can break incident routing).monitoring.prometheus- Protects against destructive Prometheus/Grafana operations like deleting time series data or dashboards/datasources.monitoring.splunk- Protects against destructive Splunk CLI/API operations like index removal and REST API DELETE calls.
Payment Packs
payment.braintree- Protects against destructive Braintree/PayPal payment operations like deleting customers or cancelling subscriptions via API/SDK calls.payment.square- Protects against destructive Square CLI/API operations like deleting catalog objects or customers (which can break payment flows).payment.stripe- Protects against destructive Stripe CLI/API operations like deleting webhook endpoints and customers, or rotating API keys without coordination.
Search Engine Packs
search.algolia- Protects against destructive Algolia operations like deleting indices, clearing objects, removing rules/synonyms, and deleting API keys.search.elasticsearch- Protects against destructive Elasticsearch REST API operations like index deletion, delete-by-query, index close, and cluster setting changes.search.meilisearch- Protects against destructive Meilisearch REST API operations like index deletion, document deletion, delete-batch, and API key removal.search.opensearch- Protects against destructive OpenSearch REST API operations and AWS CLI domain deletions.
Backup Packs
backup.borg- Protects against destructive borg operations like delete, prune, compact, and recreate.backup.rclone- Protects against destructive rclone operations like sync, delete, purge, dedupe, and move.backup.restic- Protects against destructive restic operations like forgetting snapshots, pruning data, removing keys, and cache cleanup.backup.velero- Protects against destructive velero operations like deleting backups, schedules, and locations.
Windows Packs
Native-Windows (cmd.exe + PowerShell) destructive-command protection. windows.filesystem and
windows.system are default-on on Windows (off/opt-in on Unix); windows.misc and
windows.powershell are opt-in everywhere. All patterns are case-insensitive.
windows.filesystem- Recursive/forced filesystem destruction: cmddel /s,rd /s/rmdir /s,format <drive>:; PowerShellRemove-Item -Recurse(with or without-Force;-Forceonly broadens coverage to hidden/read-only items; aliasesrm/del/rd/riincluded),Clear-Content,Clear-RecycleBin. Whitelists PowerShell-WhatIfpreviews only on cmdlets/aliases that honor it, plus temp-dir deletes.windows.system- Catastrophic disk/system operations:vssadmin delete shadowsandwmic shadowcopy delete(Volume Shadow Copy destruction — a ransomware hallmark),diskpart,Format-Volume,Clear-Disk,Remove-Partition,Initialize-Disk/Reset-PhysicalDisk,cipher /w,bcdedit /delete.windows.misc- Registry/account/service/WSL/copy destruction:reg delete,net user|localgroup /delete,sc delete,schtasks /delete,wsl --unregister(destroys a WSL distro),robocopy /MIR(mirror-delete).windows.powershell- Destructive PowerShell cmdlets: registry/provider deletes (Remove-Item HKLM:\,Remove-ItemProperty,Remove-PSDrive),Remove-LocalUser/Remove-LocalGroup,Unregister-ScheduledTask,Disable-ComputerRestore, forcedStop-Computer/Restart-Computer,Remove-VM/Remove-AppxPackage.
Careful Company (Windows) Preset
Every other pack answers "will this command destroy something?". This preset also
answers "is this command sending our data somewhere, or switching off the
controls that watch it?" — the question that matters once an agent runs on a
Windows workstation with tool-permission prompts disabled. The same policy is
applied to statically inspectable commands submitted through either
PowerShell or cmd.exe, including Cmd's caret escaping, control prefixes,
nested cmd /c / call, and command chaining. It is opt-in on every
platform, and one line enables the whole posture:
[packs]
enabled = ["careful_company_running_windows"]With this exact preset ID enabled, the hook evaluation deadline defaults to
3000 ms instead of the ordinary 1000 ms unless config or
DCG_HOOK_TIMEOUT_MS explicitly supplies another value. This changes only the
time available to reach the same fail-closed decision. Inspect the effective
value and source with dcg config --format json.
That turns on the six sub-packs below and the existing destruction coverage
the same posture needs: the current windows.*, database.* (including
Snowflake), storage.*, remote.*, backup.*, secrets.*, and cloud.*
packs. Membership is an explicit pinned list rather than a prefix rule, so a
future pack added to one of those reused categories does not silently join this
security posture — it has to be added deliberately. (A future
careful_company_running_windows.* sub-pack does join, through ordinary
category expansion.) Any member can be dropped individually with
disabled = ["remote.rsync"].
careful_company_running_windows.email- Sending mail from the workstation:Send-MailMessage,System.Net.Mail.SmtpClient, Outlook COM automation, Microsoft GraphsendMail, transactional mail-API send endpoints,aws ses send-email, SMTP CLI tools (blat,swaks,msmtp,git send-email,curl --mail-rcpt), and persistent forwarding rules (New-InboxRule -ForwardTo,Set-Mailbox -ForwardingSmtpAddress).careful_company_running_windows.chat- Chat and webhook destinations: Slack incoming webhooks and Web API writes, Teams connectors and Power Automate triggers, Discord, Telegram, Google Chat, Twilio, Zapier/IFTTT, PagerDuty, and request catchers such aswebhook.siteandinteract.sh.careful_company_running_windows.upload- HTTP file-upload primitives (-InFile,-Form,curl -T,-F field=@file,--data-binary @file,--post-file,WebClient.UploadFile,GetRequestStream,MultipartFormDataContent, BITS uploads), file-drop/paste services,gh gist create,certreq -Post, and request bodies built from file or clipboard contents.careful_company_running_windows.transfer- Outbound file transfer: scp/sftp/WinSCP to a remote destination, scripted FTP,tftp put, rsync and rclone to a remote, cloud-storage uploads (aws s3 cplocal→s3://,az storage blob upload, azcopy,gsutil cp→gs://, b2/s3cmd/mc/wrangler r2), peer-to-peer senders, WebDAV mounts, and copy LOLBins (esentutl /y,print /D:).careful_company_running_windows.tunnel- Channels that expose the workstation or bypass inspection: ngrok, cloudflared, devtunnel/code tunnel, localtunnel,tailscale funnel,ssh -R/-D, chisel/frp, ncat/netcat/socat, PowerShell raw sockets,netsh interface portproxy, DNS tunnels, and out-of-band callback domains.careful_company_running_windows.guardrails- Turning off the safety net: Defender (Set-MpPreference -Disable*/-ExclusionPath), the firewall, EDR and event-log services, BitLocker,Set-ExecutionPolicy Bypass, script-block logging, event-log clearing, dcg's ownDCG_BYPASS,dcg uninstall, allowlist grants (dcg allowlist add,dcg allow-once), runtime config overrides (DCG_DISABLE/DCG_PACKS/DCG_CONFIG), and the agent's hook config, plus unreviewed remote code (iwr | iex,powershell -EncodedCommand, mshta/regsvr32 remote payloads). Diagnosis stays open:dcg explain,dcg allowlist list, anddcg allowlist validateare whitelisted.
False positives are the design constraint. Rules require positive evidence of
egress — an attached file, a known egress host, a mutating method — so ordinary
GETs, -OutFile/curl -o downloads, and every package-manager install pass
through untouched (fetching from a known file-drop or paste host is the one
exception, and it warns rather than blocks). Requests whose destinations are all internal (loopback,
RFC1918, *.internal/*.corp/*.local, bare intranet hostnames) are
whitelisted, with the cloud metadata endpoints (169.254.169.254,
metadata.google.internal) deliberately excluded from that allowance. Searching
for a token (Select-String "Send-MailMessage" *.ps1) and dcg explain "<command>" are never blocked. git push to a named remote is untouched, and
SMB copies to a corporate share are out of scope.
Genuinely ambiguous cases warn instead of blocking (Medium severity: the
command runs and the decision is recorded) — a POST with an inline body is a
GraphQL query as often as an exfiltration. Promote them when your posture calls
for it:
[policy.rules]
"careful_company_running_windows.upload:cli-http-mutating-request" = "deny"
"careful_company_running_windows.upload:ps-http-mutating-request" = "deny"This preset carries one built-in trust boundary you should know about. While any
careful_company_running_windows.*pack is enabled, a command whose executable ishfdt(optionally path-qualified) is allowed without evaluating any pack at all — not just this preset's.hfdt rm -rf /datais permitted with the preset on and denied with it off. The exemption is structural rather than textual: it requireshfdtto be the actual executable of the whole command and refuses chains, redirection, and process substitution, sohfdt …; Invoke-RestMethod …andhfdt $(…)are evaluated normally. If you do not run that tool, this never fires; if you do, treat it as an explicit decision to trust it completely. Seedocs/careful-company-windows.md.
Other first-party internal tooling gets no such exemption and should be allowlisted, which keeps the grant narrow and recorded:
dcg allowlist add-command "mytool publish --to https://artifacts.corp.internal" \
-r "First-party internal publisher" --userOther Packs
package_managers- Protects against dangerous package manager operations like publishing packages and removing critical system packages.strict_git- Stricter git protections: blocks all force pushes, rebases, and history rewriting operations.
Enable packs in ~/.config/dcg/config.toml:
[packs]
enabled = [
# Databases
"database.postgresql",
"database.redis",
"database.supabase",
# Containers and orchestration
"containers.docker",
"kubernetes", # Enables all kubernetes sub-packs
# Cloud providers
"cloud.aws",
"cloud.gcp",
# Secrets management
"secrets.aws_secrets",
"secrets.vault",
# CI/CD
"cicd.jenkins",
"cicd.gitlab_ci",
# Messaging
"messaging.kafka",
"messaging.sqs_sns",
# Search engines
"search.elasticsearch",
# Backup
"backup.restic",
# Platform
"platform.github",
"platform.railway",
# Monitoring
"monitoring.splunk",
]Custom Packs
Create 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.
[packs]
custom_paths = [
"~/.config/dcg/packs/*.yaml", # User packs
".dcg/packs/*.yaml", # Project-local packs
]For detailed pack authoring guide, schema reference, and examples, see docs/custom-packs.md.
Validate your pack before deployment:
dcg pack validate mypack.yamlHeredoc scanning configuration:
[heredoc]
# Enable scanning for heredocs and inline scripts (python -c, bash -c, etc.).
enabled = true
# Extraction timeout budget (milliseconds).
timeout_ms = 50
# Resource limits for extracted bodies.
max_body_bytes = 1048576
max_body_lines = 10000
max_heredocs = 10
# Optional language filter (scan only these languages). Omit for "all".
# languages = ["python", "bash", "javascript", "typescript", "ruby", "perl", "go"]
# Bounded heredoc fallback (strict mode can block instead).
fallback_on_parse_error = true
fallback_on_timeout = trueCLI overrides for heredoc scanning:
--heredoc-scan/--no-heredoc-scan--heredoc-timeout <ms>--heredoc-languages <lang1,lang2,...>
Heredoc documentation:
docs/adr-001-heredoc-scanning.md(architecture and rationale)docs/patterns.md(pattern authoring + inventory)docs/security.md(threat model and incident response)
Heredoc Three-Tier Architecture
Heredoc and inline script scanning uses a three-tier pipeline designed for performance and accuracy:
Command Input
│
▼
┌─────────────────┐
│ Tier 1: Trigger │ ─── No match ──► ALLOW (fast path, <100μs)
│ (RegexSet) │
└────────┬────────┘
│ Match
▼
┌─────────────────┐
│ Tier 2: Extract │ ─── Error/Timeout ──► FALLBACK SCAN or BLOCK (strict)
│ (<1ms) │
└────────┬────────┘
│ Success
▼
┌─────────────────┐
│ Tier 3: AST │ ─── No match ──► ALLOW
│ (<5ms) │ ─── Match ──► BLOCK
└─────────────────┘
Tier 1: Trigger Detection (<100μs)
Ultra-fast regex screening to detect heredoc indicators. Uses a compiled RegexSet for O(n) matching against all trigger patterns simultaneously:
static HEREDOC_TRIGGERS: LazyLock<RegexSet> = LazyLock::new(|| {
RegexSet::new([
r"<<-?\s*(?:['\x22][^'\x22]*['\x22]|[\w.-]+)", // Heredocs
r"<<<", // Here-strings
r"\bpython[0-9.]*\b.*\s+-[A-Za-z]*[ce]", // python -c/-e
r"\bruby[0-9.]*\b.*\s+-[A-Za-z]*e", // ruby -e
r"\bnode(js)?[0-9.]*\b.*\s+-[A-Za-z]*[ep]", // node -e/-p
r"\b(sh|bash|zsh)\b.*\s+-[A-Za-z]*c", // bash -c
// ... more patterns
])
});Commands without any trigger patterns skip directly to ALLOW—no further processing needed.
Tier 2: Content Extraction (<1ms)
For commands that trigger, extract the actual content to be evaluated:
- Heredocs:
cat <<EOF ... EOF→ extracts body between delimiters - Here-strings:
cat <<< "content"→ extracts quoted content - Inline scripts:
python -c "code"→ extracts the code argument
Extraction is bounded by configurable limits:
- Maximum body size (default: 1MB)
- Maximum lines (default: 10,000)
- Maximum heredocs per command (default: 10)
- Timeout (default: 50ms)
pub struct ExtractionLimits {
pub max_body_bytes: usize,
pub max_body_lines: usize,
pub max_heredocs: usize,
pub timeout_ms: u64,
}Tier 3: AST Pattern Matching (<5ms)
Extracted content is parsed using language-specific AST grammars (via tree-sitter/ast-grep) and matched against structural patterns:
// Example: detect subprocess.run with shell=True and rm -rf
let pattern = r#"
call_expression {
function: attribute { object: "subprocess" attr: "run" }
arguments: argument_list {
contains string { contains "rm -rf" }
contains keyword_argument { keyword: "shell" value: "True" }
}
}
"#;Recursive Shell Analysis:
When 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:
if content.language == ScriptLanguage::Bash {
let inner_commands = extract_shell_commands(&content.content);
for inner in inner_commands {
// Re-evaluate inner command against all packs
if let Some(result) = evaluate_command(&inner, ...) {
if result.decision == Deny {
return result; // Block the outer command
}
}
}
}If you encounter commands that should be blocked, please file an issue.
Environment Variables
Environment variables override config files (highest priority):
DCG_PACKS="containers.docker,kubernetes": enable packs (comma-separated)DCG_DISABLE="kubernetes.helm": disable packs/sub-packs (comma-separated)DCG_VERBOSE=0-3: verbosity level (0 = quiet, 3 = trace)DCG_LOG=<filter>: hook-mode diagnostics; sends the evaluator's tracing events to stderr (DCG_LOG=debug, or atracingfilter such asdestructive_command_guard::heredoc=trace). Unset by default.DCG_QUIET=1: suppress non-error outputDCG_COLOR=auto|always|never: color modeDCG_NO_RICH=1: disable rich terminal formatting and use plain renderingDCG_NO_COLOR=1: disable colored output (same as NO_COLOR)DCG_LEGACY_OUTPUT=1: force plain output paths (same as--legacy-output)DCG_ROBOT=1: enable robot mode for JSON stdout and quiet stderrDCG_HIGH_CONTRAST=1: enable high-contrast output (ASCII borders + monochrome palette)DCG_FORMAT=text|json|sarif: default output format (command-specific — see Output Formats for which values each subcommand actually accepts; real SARIF isdcg scan-only)DCG_FAIL_CLOSED=1: block (deny) on hook input that cannot be parsed, instead of the default fail-open allow (opt-in; see Bounded Failure Policy)DCG_UNVERIFIED_DECISION=deny|ask: decision for commands dcg could not verify (evaluation timeout, or overmax_command_bytes);denysuits unattended sessions where nobody can answerask(see Bounded Failure Policy)DCG_BRIDGE_CRASH_DECISION=allow: let a command through when the OpenCode plugin or the Oh My Pi bridge started dcg but got no verdict from it (dcg crashed or was killed); the default blocks (see Bounded Failure Policy)DCG_BYPASS=1: bypass dcg entirely (escape hatch; use sparingly)DCG_CONFIG=/path/to/config.toml: use explicit config fileDCG_HEREDOC_ENABLED=true|false: enable/disable heredoc scanningDCG_HEREDOC_TIMEOUT=50: heredoc extraction timeout (milliseconds)DCG_HEREDOC_TIMEOUT_MS=50: heredoc extraction timeout (milliseconds)DCG_HEREDOC_LANGUAGES=python,bash: filter heredoc languagesDCG_AST_TIMEOUT_MS=<milliseconds>: AST-matching budget for embedded code (default 20). It can only raise the compiled-in budget, never lower it: a smaller window pushes the matcher into its bounded fallback, which denies but without naming a rule, so shrinking it from the environment would degrade analysis rather than tighten it. Lower bounds belong toDCG_HOOK_TIMEOUT_MSandDCG_HEREDOC_TIMEOUT_MS, which are measured against real workDCG_POLICY_DEFAULT_MODE=deny|ask|warn|log: global default decision mode (askrequires native operator review and fails closed on unsupported clients)DCG_HOOK_TIMEOUT_MS=<milliseconds>: explicit hook evaluation timeout (ordinary default: 1000; automaticcareful_company_running_windowspreset default: 3000)DCG_UPDATE_PIN=1: pin this install againstdcg update(#320) — the updater refuses before any network/installer work unless--replace-local-buildis passed, and the "update available" nudge is suppressed. Same asgeneral.update_pin = truein config.DCG_HISTORY_DB=/path/to/history.db: history database file (overrides[history] database_path;~is expanded). See Command History.DCG_HISTORY_DISABLED=1: never open the history database, even when[history] enabled = true.
Command History
Command history is opt-in ([history] enabled = true). When enabled, the
hook records every evaluated command (redacted per redaction_mode; the
default "pattern" replaces recognised credential shapes with placeholders and
truncates long quoted arguments) in a
SQLite database that dcg history, dcg stats, and dcg suggest-allowlist
read.
Where the database lives, highest priority first:
DCG_HISTORY_DBenvironment variable[history] database_pathin config (~expanded; relative paths resolve against the working directory)- An existing
history.dbbesideconfig.toml(~/.config/dcg/history.db) from a release before 0.15 — it keeps being used until you move it - The platform state directory:
$XDG_STATE_HOME/dcg/history.db, defaulting to~/.local/state/dcg/history.dbon Linux/macOS, and%LOCALAPPDATA%\dcg\history.dbon Windows
History is state, not configuration, so it no longer defaults into
~/.config/dcg; a sandbox that mounts the config directory read-only keeps
working. Directories dcg creates for the database are owner-only (0700).
dcg doctor prints the resolved path, which rule selected it, and whether the
hook can write there.
What a row can and cannot tell you:
hostnameis the machine that recorded the row, so databases copied off several machines can be merged and still attributed.exit_codeis always NULL on rows the hook writes. dcg runs before the command, so it never learns how the command ended. Read NULL as "unknown", not as "succeeded". History records dcg's decisions (allow, deny, warn, bypass); it cannot by itself show that an allowed command did damage.dcg history analyzeworks from those decisions. With no recorded commands it says so and makes no recommendations. A pack that never matched is listed but never recommended for removal: a guard pack that stays quiet is working.
Output Formats and DCG_FORMAT
--format (and the DCG_FORMAT env var, which seeds the default) is
command-specific: each subcommand accepts only its own set of values, and an
unrecognized value is a usage error (exit 2). DCG_FORMAT applies wherever a
command has a --format flag and is silently ignored by commands that don't.
| Command | Accepted --format values |
Notes |
|---|---|---|
dcg scan |
pretty, json, markdown, sarif |
Only command that emits real SARIF 2.1.0 |
dcg test |
pretty (alias text), json (aliases sarif, structured), toon |
|
dcg config |
pretty (alias text), json (alias sarif) |
|
dcg packs |
pretty (alias text), json (alias sarif) |
|
dcg explain |
pretty, json (alias sarif) |
|
dcg doctor |
pretty, json (alias sarif) |
|
dcg simulate |
pretty, json (alias sarif) |
|
dcg corpus |
json, pretty (alias sarif) |
|
dcg suggest-allowlist |
text, json (alias sarif) |
sarif is a JSON alias on every command except dcg scan. This is
deliberate so that setting DCG_FORMAT=sarif globally degrades gracefully —
dcg scan produces a real SARIF report while other commands fall back to their
structured JSON rather than erroring. If you need machine-readable output from a
non-scan command, prefer --format json (which is unambiguous); use dcg scan --format sarif for SARIF. --robot forces JSON regardless of --format.
Configuration Hierarchy
dcg supports layered configuration from multiple trusted sources, with higher-priority sources overriding lower ones:
- Environment Variables (DCG_* prefix) [HIGHEST PRIORITY]
- Explicit Config File (DCG_CONFIG env var)
- User Config (~/.config/dcg/config.toml)
- System Config (/etc/dcg/config.toml)
- Compiled Defaults [LOWEST PRIORITY]
An automatically discovered .dcg.toml is intentionally not a normal
precedence layer. A repository is untrusted when it is first cloned, so its
config may only add enforcement: enable built-in packs, add deny policy
entries, opt into general.fail_closed, enable
heredoc scanning, or turn off heredoc bounded fallbacks. Settings that grant
trust or reduce coverage — including allow overrides, pack disables, custom
pack paths, custom regex overrides (including block regexes), resource limits,
language filters, agent profiles, nested project overrides, and per-rule
target-path exemptions — are ignored during
automatic discovery.
Automatic project discovery reads only a direct regular file bound to the
handle it actually reads: O_NOFOLLOW plus descriptor identity on Unix
(including macOS), and a reparse-point-refusing open plus handle/path identity
on native Windows. A symli
(README truncated)
