agent-shield 1.0.0

Security scanner for AI agent extensions — offline-first, multi-framework, SARIF output
Documentation

AgentShield

Find risky behavior in MCP and AI agent extensions before they ship.

CI Release Website License: MIT OR Apache-2.0 Crates.io VS Code docs.rs

AgentShield is an offline, high-performance Rust security engine for teams shipping tool-enabled AI agents across the modern AI stack. Native adapters cover MCP servers, OpenClaw skills, Hermes Agent configs, CrewAI, LangChain/LangGraph, GPT Actions, and Cursor Rules; the same checks help harden repositories built around OpenAI Agents SDK, Claude Code, Claude Desktop MCP setups, Browser Use, FastMCP, GitHub MCP Server, Playwright MCP, and other tool-heavy workflows.

It catches command injection, credential exfiltration, SSRF, unsafe file access, runtime package installs, prompt-injection surfaces, and dependency hygiene issues before an agent can call those tools.

AgentShield runs as a CLI, GitHub Action, VS Code extension, or Rust library. It operates 100% offline, keeping source code on your machine, and emits console, JSON, SARIF for GitHub Code Scanning, and standalone HTML reports. The current release line is 1.0.0 (General Availability).

At a glance

Area What AgentShield does
Scanner surface Normalizes seven framework/client families into one IR: MCP, OpenClaw, Hermes Agent, CrewAI, LangChain/LangGraph, GPT Actions, and Cursor Rules.
Interprocedural Taint Deep cross-function & cross-method call-graph analysis tracking untrusted inputs through utility wrappers to execution sinks in Python and TypeScript.
Detection 20 built-in contextual rules plus a declarative YAML custom rule engine (.agentshield/rules/*.yaml).
Automated Remediation Instant auto-fixing (agentshield fix) and VS Code lightbulb code actions (Cmd + .) for unsafe deserializers and unpinned dependencies.
Runtime Guard Reverse proxy for MCP stdio and HTTP/SSE streams inspecting tool calls in real time and redacting leaked secrets.
Workflow fit Works locally, in CI, in VS Code, and in GitHub Code Scanning without sending source code to a hosted service.

For runtime guard scope and roadmap, see docs/RUNTIME_GUARD.md.

Works With

AgentShield is useful anywhere an agent can call local tools, remote APIs, browser automation, file operations, shell commands, or MCP servers.

Ecosystem How AgentShield helps
Claude Desktop and Claude Code Scan MCP servers and tool repositories before adding them to Claude MCP configs or coding-agent workflows.
Cursor and Cursor Rules Detect risky agent guidance, MCP server definitions, and tool code that can reach files, commands, or the network.
OpenAI Agents SDK Scan tool implementations, OpenAPI/GPT Actions surfaces, and MCP-connected repos used by OpenAI agent apps.
LangGraph and LangChain Analyze Python/TypeScript tool code and dependency surfaces before agents execute tools.
CrewAI Check Python CrewAI tool projects for command execution, credential exfiltration, SSRF, and unsafe file access.
FastMCP, GitHub MCP Server, and Playwright MCP Scan MCP server code, manifests, schemas, dependencies, and provenance before publishing or installing.
Browser Use and browser automation agents Catch risky command, network, file, and dependency patterns in tool-enabled automation repos.

Runnable examples live under examples/, with focused guides for Claude MCP security, MCP security scanning, and OpenAI Agents security.

Why AgentShield?

AI agents are being connected to tools that can execute commands, read and write files, make HTTP requests, install packages, and call external services. A single malicious or poorly-written extension can:

  • Exfiltrate credentials by reading environment variables or local secret files and sending them to an attacker-controlled endpoint.
  • Execute arbitrary commands by passing user-controlled input into shell or process APIs.
  • Install backdoors at runtime through package manager calls inside tool handlers.
  • Proxy SSRF requests by fetching URLs derived from tool arguments.
  • Leak sensitive data to model context through unguarded prompts, tool results, or rule files.

AgentShield catches these patterns with static analysis, framework adapters, policy evaluation, suppressions, baselines, egress policy generation, attestations, and SARIF output for GitHub Code Scanning.

Use it with general security scanners

AgentShield complements general-purpose security tooling; it is not a replacement for SAST, secret scanning, or broad dependency analysis. A practical security stack is:

Tool Primary coverage Why keep AgentShield
CodeQL General SAST for code vulnerabilities and quality issues CodeQL is broad; AgentShield models agent/tool surfaces such as MCP tools, prompts, tool schemas, and egress.
Gitleaks Hardcoded secrets across Git history and source files Gitleaks is the right secret scanner; AgentShield focuses on secrets flowing through tools, logs, responses, and agent context.
Semgrep Custom SAST rules, language-specific checks, SCA, and security policy Semgrep is flexible and broad; AgentShield ships opinionated agent/MCP detectors and a normalized IR for supported agent frameworks.
AgentShield MCP, agent tools, prompt surfaces, filesystem/network/process capabilities, egress policy, SARIF, and runtime guard experiments This is the agent-specific layer that catches risks other scanners usually see only indirectly.

Use agentshield ci install --suite when you want a starter GitHub Actions workflow that runs CodeQL, Gitleaks, Semgrep CE, and AgentShield together.

How it compares

Feature AgentShield mcp-scan Invariant Labs
Rust single binary Yes No No
Offline / local-first Yes Partial No
Multi-framework adapters Yes (7 frameworks) MCP-focused MCP-focused
Interprocedural Call-Graph Taint Yes No No
Declarative Custom Rules (.yaml) Yes No No
Automated Remediation (fix) Yes No No
Runtime Guard MCP Proxy (stdio/SSE) Yes No No
Static analysis tree-sitter + AST + regex Regex-oriented Runtime/cloud-oriented
SARIF & HTML output Yes No No
GitHub Action & VS Code Extension Yes No No

Quick Start

VS Code Extension

Install the AgentShield VS Code Extension for inline security findings and lightbulb quick-fixes:

  • Inline Diagnostics: Findings are highlighted as you type and on file save.
  • Lightbulb Quick-Fixes (Cmd + . / Alt + Enter): Instant 1-click remediation for unsafe deserializers (yaml.load $\to$ safe_load) and unpinned dependencies.
  • Interactive Suppressions: Suppress false positives with a rationale saved directly to .agentshield.toml.

GitHub Action

Add to .github/workflows/security.yml:

name: Agent Security
on: [push, pull_request]

permissions:
  actions: read
  contents: read
  security-events: write

jobs:
  scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
      - uses: aiconnai/agentshield@main
        with:
          path: '.'
          fail-on: 'high'
          ignore-tests: true
          strict: true # set false only when no supported adapter layout is expected
          upload-sarif: true

Findings appear as PR annotations and in the repository's Security > Code scanning tab when SARIF upload is enabled.

CLI

# Install the v1.0.0 GA release with the full feature set
cargo install --git https://github.com/aiconnai/agentshield --tag v1.0.0 --features full --force

# First-run setup: config + explained first scan
agentshield quickstart

# Scan an agent extension or MCP repository
agentshield scan . --ignore-tests --fail-on high --explain

# Automatically remediate fixable findings (preview diff with --dry-run)
agentshield fix . --dry-run
agentshield fix .

# Scan with custom declarative rules
agentshield scan . --rules-dir .agentshield/rules

# Run runtime guard reverse-proxy for remote MCP SSE/HTTP endpoint
agentshield guard --listen 127.0.0.1:8080 --target http://127.0.0.1:3000

# Discover allowlisted local client configs without executing them
agentshield discover --no-default-paths --root .

# Add a GitHub Actions workflow
agentshield ci install

# Add a broader security suite: CodeQL + Gitleaks + Semgrep CE + AgentShield
agentshield ci install --suite

# Adopt in an existing repo without blocking on known findings
agentshield scan --write-baseline .agentshield-baseline.json
agentshield ci install --baseline .agentshield-baseline.json

# Generate a standalone HTML report
agentshield scan ./my-agent-extension --format html --output report.html

# List all built-in and custom rules
agentshield list-rules

If you only need static scanning in a published crates.io version, cargo install agent-shield is also supported. Use the GitHub tag command above when you need the latest release line before crates.io has been updated.

Pre-built binaries

Download from the latest release for Linux, macOS, and Windows targets.

For container consumers, the release image tag is:

ghcr.io/aiconnai/agentshield:1.0.0

Docker

The GHCR image is built with the full feature set, including runtime wrap support and experimental runtime guard commands. The image is published for linux/amd64 and linux/arm64.

docker pull ghcr.io/aiconnai/agentshield:1.0.0
docker run --rm -v "$PWD:/scan" ghcr.io/aiconnai/agentshield:1.0.0 scan .
docker run --rm ghcr.io/aiconnai/agentshield:1.0.0 --version

If the GHCR package is private in your organization, authenticate first:

gh auth refresh -h github.com -s read:packages
gh auth token | docker login ghcr.io -u "$(gh api user --jq .login)" --password-stdin

From source

git clone https://github.com/aiconnai/agentshield.git
cd agentshield
cargo build --release
./target/release/agentshield scan /path/to/agent-extension

Token-Optimized Local Checks with RTK

AgentShield can produce noisy command output during local development, especially from cargo test, cargo clippy, and scanner runs that emit JSON or SARIF. If rtk is installed, use the optional wrapper to reduce output shown to humans and coding agents:

scripts/rtk-check.sh quick
scripts/rtk-check.sh test
scripts/rtk-check.sh clippy
scripts/rtk-check.sh scan-fixture

The wrapper is intentionally local-only. RTK filters local command output only. It must not alter AgentShield JSON, SARIF, HTML, or console output contracts consumed by users, clients, CI, or GitHub Code Scanning.

Use raw output for debugging, audit, and security decisions:

scripts/rtk-check.sh raw -- cargo test
scripts/rtk-check.sh raw -- cargo run -- scan tests/fixtures/mcp_servers/safe_calculator --format sarif --output target/agentshield/scan.sarif

Policy:

  • Use filtered output for fast local feedback.
  • Use raw output when investigating test failures, parser bugs, detector behavior, or security-sensitive findings.
  • Always write complete json and sarif reports to files when clients or CI consume them.

Supported Frameworks

AgentShield runs all matching adapters in a repository instead of stopping at the first match.

Framework Status Adapter coverage
MCP (Model Context Protocol) Supported MCP server manifests, Python/TypeScript/JavaScript source, tool schemas, dependencies, provenance
OpenClaw Supported SKILL.md skill files plus related source/dependency surfaces
Hermes Agent Supported Hermes config/profile files, mcp_servers, .hermes.md, skill trees, optional MCP manifests
CrewAI Supported Python projects detected from dependency metadata or imports
LangChain / LangGraph Supported LangChain/LangGraph dependency metadata, imports, and langgraph.json
GPT Actions Supported Action/OpenAPI-style surfaces for custom GPT integrations
Cursor Rules Supported Cursor rule files and related agent guidance surfaces

CLI Commands

Command Purpose
agentshield discover Read allowlisted local client configuration paths without execution, network access, or automatic scanning; use --no-default-paths, repeated --root, --format console|json, and --explain to control consent and output.
agentshield scan [path] Scan an agent extension directory and emit console, JSON, SARIF, or HTML output.
agentshield scan [path] --experimental-risk Add an informational, versioned risk index to console or JSON output without changing policy or exit status.
agentshield scan [path] --explain Print a console-only gate, coverage, confidence, grouped findings, next-actions, and limits summary.
agentshield quickstart [path] Create first-run config, suggest CI setup, run the first scan, and explain the result.
agentshield ci install Generate a GitHub Actions workflow for AgentShield.
agentshield ci install --suite Generate a broader GitHub Actions workflow with CodeQL, Gitleaks, Semgrep CE, and AgentShield.
agentshield ci install --baseline <path> Generate a workflow that filters known findings through a baseline file.
agentshield list-rules List available detection rules as a table or JSON.
agentshield doctor [path] Print environment, config, compile-feature, and adapter diagnostics.
agentshield init Generate a starter .agentshield.toml config file.
agentshield fix [path] Automatically fix deterministic security issues (unsafe deserializers, unpinned dependencies); use --dry-run to preview unified diffs.
agentshield suppress <fingerprint> Add a suppression entry with a required reason and optional expiry.
agentshield list-suppressions Show suppressions configured in .agentshield.toml.
agentshield certify [path] Generate a DSSE attestation envelope for scan results.
agentshield wrap --policy <path> -- <command> Enforce an egress policy through a local HTTP proxy when built with the runtime feature.
agentshield guard --stdin Evaluate one runtime event JSON document when built with the runtime-guard feature.
agentshield guard --mcp-proxy [-- <server cmd...>] EXPERIMENTAL: evaluate line-delimited MCP JSON-RPC tools/call messages, block unsafe calls, and either emit forward markers or bridge stdio to a spawned downstream MCP server when built with the runtime-guard feature.

Useful scan options include --config, --format, --fail-on, --output, --ignore-tests, --explain, --experimental-risk, --baseline, --write-baseline, and --emit-egress-policy. Configured [scan] include and [scan] exclude filters scope source and metadata-derived findings before detectors run.

For mature repositories with existing findings, write a baseline first and use it in CI:

agentshield scan --write-baseline .agentshield-baseline.json
agentshield scan --baseline .agentshield-baseline.json --explain
agentshield ci install --baseline .agentshield-baseline.json

--explain is intentionally console-only. It will not append text to JSON, SARIF, or HTML output. Explain output includes the scan root, metadata root when different, and hotspot summaries for concentrated blocking findings.

--experimental-risk is a separate console/JSON-only mode and cannot be combined with --explain. Its versioned index is informational: it does not change findings, PASS/FAIL, policy thresholds, baselines, suppressions, or the process exit status. SARIF, HTML, and DSSE remain unchanged.

Detection Rules

AgentShield ships 20 built-in contextual rules covering command execution, credential exfiltration, composite toxic flows, SSRF, arbitrary file access, runtime package installation, prompt injection surfaces, excessive capabilities, dependency hygiene, dynamic code execution, metadata service access, unsafe deserialization, and secret leakage.

Use the CLI for the authoritative rule list in your installed version:

agentshield list-rules
agentshield list-rules --format json

Custom Declarative Rules

You can define custom organization security policies in .agentshield/rules/*.yaml or pass --rules-dir <path>:

id: "ORG-001"
name: "Banned Production Credentials"
description: "Detects legacy hardcoded connection strings"
severity: "high"
attack_category: "credential_access"
cwe_id: "CWE-798"
match:
  regex: "postgres://prod_admin:[^@]+@"
  file_glob: "*.{py,ts,js}"
  message: "Hardcoded production database connection string detected"
  remediation: "Inject database credentials via environment variables or secret store"

Banned dependency rules and prohibited tool name rules are also supported:

id: "ORG-002"
name: "Banned Deprecated Library"
description: "Disallow telnetlib in agent tools"
severity: "medium"
attack_category: "supply_chain"
match:
  banned_dependencies:
    - name: "telnetlib"
      reason: "Insecure unencrypted remote protocol"
  tool_name_regex: "^telnet_"

Output Formats

Format Flag Use case
Console --format console Local development default
JSON --format json Programmatic consumption and fingerprint extraction
SARIF --format sarif GitHub Code Scanning and compatible tools
HTML --format html Shareable standalone reports

Configuration

Trust workflows

AgentShield includes trust workflow documentation for baselines, suppressions, certification attestations, and egress enforcement:

  • docs/BASELINES.md: write and use .agentshield-baseline.json for known findings.
  • docs/SUPPRESSIONS.md: suppress individual findings by fingerprint with required reasons and optional expiry.
  • docs/CERTIFICATION.md: generate unsigned or Ed25519-signed DSSE attestations.
  • docs/EGRESS.md: emit agentshield.egress.toml and enforce it with agentshield wrap.

Release binaries are built with the full feature set, including Python parsing, TypeScript parsing, runtime wrap support, and experimental runtime guard commands. If building from source, use cargo build --features full --release to include agentshield wrap and agentshield guard.

Create .agentshield.toml in your project root or run agentshield init:

[policy]
# Minimum severity to fail the scan: info, low, medium, high, critical
fail_on = "high"

# Rules to skip entirely
ignore_rules = ["SHIELD-008"]

# Downgrade specific rules
[policy.overrides]
"SHIELD-012" = "info"

[scan]
# Skip test files before parsing
ignore_tests = true

# Optional path filters are relative to the scan root.
# Empty include means all scan-supported files are eligible.
# Use ** for recursive directories; * and ? stay within one path segment.
include = ["src/**", "tools/**"]
exclude = ["legacy/**", "**/generated/**", "vendor/**"]

[runtime.proxy]
# Runtime MCP proxy guard blocking threshold: block, warn, or never.
fail_on = "block"

[[runtime.proxy.tool]]
name = "calculator.add"
fail_on = "never"

Suppressions can be added through agentshield suppress <fingerprint> --reason "..." after obtaining finding fingerprints from JSON output.

When both include and exclude match a file, exclude wins. Use agentshield scan . --explain to confirm the active path filters and parsed source-file count before relying on a focused scan in CI. Path filter matching is case-sensitive, accepts / on all platforms, treats leading ./ or / as relative to the scan root, and treats a trailing slash such as legacy/ as matching that directory's contents.

Exit Codes

Code Meaning
0 Scan passed with no findings above threshold
1 Scan failed with findings above threshold
2 Scan error (e.g., invalid config); no supported adapter found is surfaced as scanner error and can be controlled by action strict mode
3 Runtime guard blocked or failed closed on invalid runtime input

Language Support

Language Parser Feature flag
Python Regex parser with source/sink patterns python compatibility flag (default)
TypeScript/TSX tree-sitter AST with fallback patterns typescript (default)
JavaScript/JSX tree-sitter AST through TypeScript grammar support typescript (default)
Shell Regex parser always on
JSON Schema / OpenAPI-style schemas Schema parser always on

Go, Ruby, Java, and Rust source files are not execution-parsed or included in the normalized execution surface in this release. They may be scanned by other tools in a security stack, but AgentShield does not claim language-level source or taint coverage for them yet.

TypeScript tree-sitter support is feature-gated; the Python compatibility flag keeps existing build commands stable:

cargo build --no-default-features
cargo build --features python
cargo build --features full

The full feature enables language parsers plus the runtime proxy used by agentshield wrap and the experimental runtime guard commands.

Architecture

CLI / GitHub Action / Library API
       |
       v
Scan Engine -> ScanReport
       |
       v
Adapters -> Parsers -> Cross-file analysis -> Unified IR (ScanTarget)
       |
       v
Rule Engine -> Policy / Suppressions / Baseline filtering
       |
       v
Console / JSON / SARIF / HTML / DSSE attestation

Adapters translate framework-specific files into a unified intermediate representation. Detectors consume only that IR, so new frameworks can be added without rewriting every rule. Policy, suppressions, and baselines are separate from detection so scans remain explainable and repeatable.

Security Policy

Please report vulnerabilities privately. See SECURITY.md for supported versions, reporting guidance, and disclosure scope.

Development

cargo test
cargo clippy -- -D warnings
cargo fmt --check
cargo run -- scan tests/fixtures/mcp_servers/vuln_cmd_inject
cargo run -- list-rules

For release-specific notes, see docs/releases/0.8.7.md, docs/releases/0.8.8.md, and docs/RELEASE_CHECKLIST.md.