HOL Guard: Open-Source Antivirus for AI Agents
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Stop risky AI actions before they compromise your machine. HOL Guard is a local-first security layer for AI agents, tools, plugins, skills, MCP servers, and package installs. Install HOL Guard Read the documentation PyPI Package ( hol-guard)Report an Issue |
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HOL Guard reviews agent actions before they run: shell commands, file access, package installs, and MCP tool calls. It detects secret exposure, destructive operations, prompt injection, and supply-chain risks, then allows, blocks, or requests approval according to your policy.
Run it locally without an account. Use the CLI and local dashboard to manage protection, resolve approvals, and inspect decision history. Optional Guard Cloud adds shared history, team policy, and fleet management.
Get started · Supported agents · Plugin scanner · Documentation · Contributing
Install HOL Guard
Requires Python 3.10 or newer and pipx.
pipx install hol-guard
hol-guard init
The first-run wizard discovers supported agents and walks you through protection setup. It asks before each setup change, including opening the dashboard, installing agent integrations, and connecting optional cloud services.
Check your installation:
hol-guard --version
hol-guard status
To update an existing installation:
hol-guard update
For manual setup, see the installation guide. Release details and prereleases are on the releases page.
What HOL Guard Protects
| Surface | Protection |
|---|---|
| Shell commands and file access | Reviews destructive operations, sensitive file access, credential exposure, and suspicious outbound commands. |
| Package installs | Evaluates supported package-manager operations against supply-chain intelligence before installation. |
| Plugins, skills, and agent configuration | Inventories local artifacts and reviews new or changed tools before launch. |
| MCP servers and tools | Inspects server configuration and reviews tool calls through supported hooks and managed proxies. |
| Prompts and tool results | Screens supported events for prompt injection and sensitive content. |
| Approvals and evidence | Routes decisions to native prompts or the approval center, and records local receipts for review. |
Guard connects through native agent hooks, managed MCP proxies, and launch integrations. Coverage depends on the events each agent exposes; the support matrix documents enforcement, approval delivery, and failure behavior per integration.
Supported AI Agents
Codex, Claude Code, GitHub Copilot CLI, Cursor, Cline, Gemini CLI, Grok, Hermes, Kimi Code, Pi, oh-my-pi, OpenClaw, OpenCode, Antigravity, and ZCode.
For example, to set up Codex explicitly:
hol-guard install codex
hol-guard run codex --dry-run
hol-guard run codex
The dry run records the current artifact state before launch. For Codex, Guard installs native pre-tool hooks and refuses a managed launch if those hooks are missing or disabled.
Agent support matrix · Troubleshooting
Everyday Use
| Task | Command |
|---|---|
| Check protection status | hol-guard status |
| Diagnose an agent integration | hol-guard doctor codex |
| Inspect changes before launch | hol-guard diff codex |
| Review pending approvals | hol-guard approvals |
| Approve or deny a request | hol-guard approvals approve <request-id> / hol-guard approvals deny <request-id> |
| Read decision history | hol-guard receipts |
| List tracked artifacts | hol-guard inventory |
| Export an AI bill of materials | hol-guard abom --format json |
| Scan workspace dependencies | hol-guard supply-chain scan |
| Connect optional cloud sync | hol-guard connect |
Understand a paused command
Inspect the command's classification and matching rules:
hol-guard command test 'rm -rf ./build'
hol-guard command explain 'git clean -ndx'
hol-guard command extensions command.git --json
command test and command explain inspect the command without executing it or creating an approval. Use hol-guard approvals to resolve a pending request and hol-guard receipts to review the recorded decision.
The Extension directory lists command coverage generated from the runtime registry. External contributions require explicit opt-in; required core protections remain enabled. To add coverage, follow the Extension contribution guide.
Check a package
hol-guard supply-chain sync
hol-guard supply-chain scan
hol-guard supply-chain explain minimist@1.2.5 --ecosystem npm
The package verdict includes the available advisory evidence and ecosystem coverage. See the get-started guide for package-manager interception and the remediation guide for handling false positives.
Plugin Scanner
This repository also ships plugin-scanner, a CLI for maintainers who want security and quality checks before publishing agent plugins, skills, and MCP integrations.
pipx install plugin-scanner
plugin-scanner scan .
plugin-scanner lint .
plugin-scanner verify .
| Command | Purpose |
|---|---|
scan |
Security findings and a quality report across detected package surfaces. |
lint |
Rule-level authoring feedback. |
verify |
Install-surface and runtime readiness checks. |
submit |
A submission artifact for one plugin package. |
doctor |
Component diagnostics and troubleshooting bundles. |
The scanner detects Codex, Claude Code, DeepSeek Harness, Gemini CLI, Kimi Code, and OpenCode package formats. Use plugin-scanner --list-ecosystems to list them or --ecosystem to select one. At a Codex marketplace root, it discovers local plugin entries automatically.
Checks cover manifests, secrets, MCP transport and command configuration, approval defaults, skills, dependency lockfiles, and GitHub Actions permissions. Optional Cisco integrations add skill and MCP analysis. Reports support text, JSON, Markdown, and SARIF.
plugin-scanner scan . --format sarif --output plugin-scanner.sarif
plugin-scanner scan . --fail-on-severity high
Quality grades use the checks applicable to each package. Trust scoring has separate provenance and weights; see the skill, MCP, and plugin scoring references.
GitHub Actions
Add the scanner to a plugin repository:
name: Plugin security
on: [push, pull_request]
permissions:
contents: read
jobs:
scan:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
- uses: hashgraph-online/ai-plugin-scanner-action@fdb49f9d85321a2ced2933301b395dd3c1ce9c8f # v1.2.631
with:
plugin_dir: "."
min_score: 80
fail_on_severity: high
See the action documentation for SARIF uploads, submission workflows, and machine-readable outputs. The action source is maintained in action/.
Optional Cisco analysis
The baseline packages work without Cisco dependencies. To add Cisco skill scanning, use Python 3.11 through 3.14 and install the extra in an isolated environment:
pipx install 'plugin-scanner[cisco]'
For Cisco MCP analysis, use the repository's Docker image or the cisco-mcp dependency group:
uv sync --extra dev --extra cisco --group cisco-mcp --python 3.13
uv run plugin-scanner scan . --cisco-skill-scan on --cisco-mcp-scan on
The published cisco extra provides skill scanning; the separate cisco-mcp group supplies the MCP scanner. Dependency versions and Python constraints are maintained in pyproject.toml.
Ecosystem Support
| Ecosystem | Detection surfaces |
|---|---|
| Codex | .codex-plugin/plugin.json, marketplace.json, .agents/plugins/marketplace.json |
| Claude Code | .claude-plugin/plugin.json, .claude-plugin/marketplace.json |
| DeepSeek Harness | package.json with dsh.bundle, declared patches, and Cordis apply(ctx) exports |
| Gemini CLI | gemini-extension.json, commands/**/*.toml |
| Kimi Code | kimi.plugin.json, .kimi-plugin/plugin.json, declared skills, agents, commands, prompts, and MCP servers |
| OpenCode | opencode.json, opencode.jsonc, .opencode/commands, .opencode/plugins |
Use --ecosystem auto to detect supported packages in a repository, or select an ecosystem explicitly:
plugin-scanner scan ./plugins-repo --ecosystem claude
plugin-scanner scan ./dsh-plugin --ecosystem deepseek-harness
What The Scanner Checks
| Category | Coverage |
|---|---|
| Manifest validation | Required fields, versions, declared paths, interface metadata, links, and assets. |
| Security | Hardcoded secrets, unsafe MCP commands and transports, and risky approval defaults. |
| Operational security | GitHub Actions permissions and pinned dependencies, privileged checkout patterns, Dependabot, and lockfiles. |
| Plugin packaging | README and license files, skill frontmatter, ignore rules, and accidentally committed environment files. |
| Marketplace | Manifest validity, local package discovery, and safe source paths. |
| Skill and MCP analysis | Analyzer availability, findings, and analyzability from optional Cisco integrations. |
| Code quality | Dynamic code execution and shell-injection patterns. |
How Trust Scoring Works
Plugin Scanner reports a quality grade alongside trust provenance. Quality scores are normalized across applicable checks, so optional surfaces do not inflate a package's grade.
Skill trust uses the HCS-28 baseline adapter IDs, weights, and denominator rules. MCP and Codex plugin trust use explicit adapters, weights, and contribution modes documented in the local specifications:
CLI Usage
# Structured security report
plugin-scanner scan ./my-plugin --format json --profile public-marketplace
# Inspect authoring rules
plugin-scanner lint ./my-plugin --list-rules
plugin-scanner lint ./my-plugin --explain README_MISSING
# Apply supported mechanical fixes
plugin-scanner lint ./my-plugin --fix --profile strict-security
# Verify package readiness; --online permits live probes
plugin-scanner verify ./my-plugin --format json
plugin-scanner verify ./my-plugin --online --format text
# Generate a submission artifact for one plugin
plugin-scanner submit ./my-plugin --profile public-marketplace --attest dist/plugin-quality.json
# Collect component diagnostics
plugin-scanner doctor ./my-plugin --component mcp --bundle dist/doctor.zip
For a repository marketplace, scan, lint, verify, and doctor can target the root. submit targets one plugin package.
Codex Spec Alignment
The scanner recognizes Codex plugin manifests, interface metadata, declared assets, and marketplace packages:
- Local manifest paths use
./prefixes;lint --fixpreserves or adds them. .agents/plugins/marketplace.jsonis the preferred marketplace location, with rootmarketplace.jsonsupported for compatibility.- Interface validation checks declared links and assets without requiring an undocumented
typefield. verify --onlinechecks HTTP remote reachability. Stdio server execution is skipped for manual review.
See the Codex plugin documentation and Model Context Protocol specification for upstream formats.
Config + Baseline Example
Configure the scanner in .plugin-scanner.toml:
[scanner]
profile = "public-marketplace"
baseline_file = "baseline.txt"
ignore_paths = ["tests/*", "fixtures/*"]
[rules]
disabled = ["README_MISSING"]
severity_overrides = { CODEXIGNORE_MISSING = "low" }
The GitHub Action requires trust_repository_policy: true before repository-owned configuration and baselines can change its verdict. Enable that option only for policy you intend the workflow to trust.
Report Formats
| Format | Use |
|---|---|
text |
Terminal summaries with category totals and findings. |
json |
Structured reports for scripts and integrations. |
markdown |
Review-ready reports for pull requests and issues. |
sarif |
GitHub code scanning and security automation. |
GitHub Action
The AI Plugin Scanner Action supports security gates, SARIF uploads, submission intake, and registry payloads. Its source lives in action/, and the publication workflow distributes the action bundle.
The legacy HOL Codex Plugin Scanner Action remains available for existing workflows.
Plugin Author Submission Flow
Use submission_enabled: true to open or reuse a submission issue when a plugin meets the configured threshold. submission_token must have permission to create issues in the target submission repository. The action emits submission status and issue URLs as outputs.
See the action's input reference for submission_score_threshold, submission_token, and the target repository options.
Registry Payload For Plugin Ecosystem Automation
Set registry_payload_output to write a machine-readable payload for a registry or badge pipeline. The action also exposes score, grade, grade_label, max_severity, and findings_total outputs and can write a job summary.
The HOL Registry Broker plugin is an example of an agent plugin in the HOL Plugin Registry. Its registry listing provides current trust information.
Why HOL Guard
AI agents can run commands, install dependencies, read files, and call external tools within one session. HOL Guard reviews those actions at supported execution points and keeps the policy decision, approval request, and receipt together.
Use it for AI agent security on a developer machine, MCP security around connected tools, and supply-chain checks for packages and plugins. Teams can add Guard Cloud for shared approvals and policy management while retaining local protection.
Frequently Asked Questions
What is HOL Guard?
HOL Guard is open-source antivirus and runtime protection for AI agents. It reviews supported tool calls, shell commands, file access, and package operations for risks such as secret exposure, prompt injection, destructive actions, and malicious dependencies.
Does HOL Guard work without a cloud account?
Yes. Local protection, CLI commands, approvals, and receipts work without signing in. Guard Cloud is optional and adds synchronized evidence, team controls, and fleet visibility. See Local Guard vs. Guard Cloud for the feature boundary.
Which AI agents does HOL Guard support?
Guard includes adapters for Codex, Claude Code, GitHub Copilot CLI, Cursor, Cline, Gemini CLI, Grok, Hermes, Kimi Code, Pi, oh-my-pi, OpenClaw, OpenCode, Antigravity, and ZCode. The support matrix explains which events and enforcement paths each adapter supports.
What is the difference between HOL Guard and Plugin Scanner?
Install hol-guard to protect agent activity on your machine. Install plugin-scanner to inspect plugin packages and enforce security and quality checks in CI. This repository builds and publishes both distributions.
How does HOL Guard protect MCP servers?
Guard inspects MCP server configuration and reviews supported MCP tool calls through agent hooks and managed proxies. Plugin Scanner checks MCP configuration and HTTP remote reachability; optional Cisco MCP analysis adds static security findings.
Why did Guard pause my command?
The action may need approval under your active policy, or its tools or artifacts may have changed. Start with hol-guard approvals, inspect the command with hol-guard command explain '<command>', and use hol-guard receipts to review the recorded decision.
Documentation
| Guide | Contents |
|---|---|
| Get started | Installation, manual setup, package protection, and common commands. |
| Agent support | Integration coverage and approval behavior. |
| Architecture | Runtime components and decision flow. |
| Policy specification | GuardPolicy document format. |
| Policy recipes | Configuration examples for common workflows. |
| Extensions | Built-in command rules and contribution guidance. |
| Local vs. cloud | Local capabilities and optional cloud services. |
| Troubleshooting | Diagnosis and recovery. |
| Security | Vulnerability reporting and disclosure policy. |
Development
Clone the repository and install the development dependencies with uv:
git clone https://github.com/hashgraph-online/hol-guard.git
cd hol-guard
uv sync --extra dev
uv run ruff check src tests
uv run ruff format --check src tests
uv run pytest --tb=short
uv build
For optional Cisco coverage, use the dependency group command above. See CONTRIBUTING.md for contribution requirements and the testing matrix for integration tests.
Resources
- HOL Plugin Registry
- HOL Plugin Security dataset on Hugging Face
- HOL Standards Documentation
- OpenAI Codex Plugin Documentation
- Model Context Protocol Documentation
- Cisco AI Skill Scanner
- Cisco AI MCP Scanner
- HOL GitHub Organization
Community
Maintained by Hashgraph Online.
License
Licensed under Apache-2.0.
1 maintainer
Release files for plugin-scanner 3.0.127
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| plugin_scanner-3.0.127.tar.gz | 9.1 MB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| plugin_scanner-3.0.127-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 13.5 MB
Release files / plugin_scanner-3.0.127.tar.gz
| Download URL | plugin_scanner-3.0.127.tar.gz |
|---|---|
| Size | 9.1 MB |
| Tags | Source |
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| Uploaded via |
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Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
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PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
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