AgentGuard Python SDK

Lightweight Python client for AgentGuard — the firewall for AI agents.

• Zero runtime dependencies for the core SDK (stdlib urllib).
• Fail-closed by default — if the proxy is unreachable, check() returns DENY.
• Framework adapters for LangChain, CrewAI, browser-use, and MCP, gated behind optional extras.

Deep reference: docs/SDK_PYTHON.md — full API, exception hierarchy, fail-mode details, adapter internals.

Install

pip install agentguardproxy

# With framework adapters
pip install agentguardproxy[langchain]
pip install agentguardproxy[crewai]
pip install agentguardproxy[browser-use]
pip install agentguardproxy[all]

Quick start

from agentguard import Guard

guard = Guard(
    base_url="http://localhost:8080",   # or set AGENTGUARD_URL
    agent_id="my-agent",
    api_key="…",                        # or set AGENTGUARD_API_KEY (needed for approve/deny/status)
)

result = guard.check("shell", command="rm -rf ./old_data")

if result.allowed:
    execute(command)
elif result.needs_approval:
    print(f"Approve at: {result.approval_url}")
    # Block until a human resolves it, or 5 min deadline, whichever first
    final = guard.wait_for_approval(result.approval_id, timeout=300)
    if final.allowed:
        # Replay the approval: consumes the one-shot ALLOW, reserves cost,
        # and audits the execution. The status poll alone spends nothing.
        replay = guard.check("shell", command=command, approval_id=result.approval_id)
        if replay.allowed:
            execute(command)
else:
    print(f"Blocked: {result.reason}")

Environment variables

Fail mode

# Default: fail closed. Proxy unreachable → CheckResult(decision="DENY", reason="AgentGuard unreachable (deny): …")
guard = Guard("http://localhost:8080")

# Opt in to fail open. Proxy unreachable → CheckResult(decision="ALLOW", reason="AgentGuard unreachable (allow): …")
# Use only when your threat model treats AgentGuard as advisory.
guard = Guard("http://localhost:8080", fail_mode="allow")

Three classes of transport failure are caught: urllib.error.URLError (connection refused / DNS / SSL), OSError (post-connect timeouts and resets), and json.JSONDecodeError (garbage response body).

The @guarded decorator

from agentguard import Guard, guarded, AgentGuardDenied, AgentGuardApprovalRequired

guard = Guard("http://localhost:8080", agent_id="my-agent")

@guarded("shell", guard=guard)
def run_command(cmd: str):
    os.system(cmd)

try:
    run_command("ls")
    run_command("rm -rf /")        # raises AgentGuardDenied
except AgentGuardDenied as e:
    log(f"blocked: {e.result.reason}")

On REQUIRE_APPROVAL the decorator raises AgentGuardApprovalRequired immediately. To block until a human resolves it, opt in:

@guarded("cost", guard=guard, wait_for_approval=True, approval_timeout=300)
def expensive_call(prompt: str): ...

All three exceptions (AgentGuardDenied, AgentGuardApprovalRequired, AgentGuardApprovalTimeout) extend PermissionError, so existing except PermissionError: handlers keep working unchanged.

Framework adapters

LangChain

from agentguard.adapters.langchain import GuardedToolkit

toolkit = GuardedToolkit(
    tools=my_tools,
    guard_url="http://localhost:8080",
    agent_id="langchain-agent",
)
agent = create_react_agent(llm, toolkit.tools, prompt)

Scope is inferred from each tool's name/description (http/api→network, file/path→filesystem, browser→browser, shell→shell) and upgraded at call time if the input dict contains url, domain, or path keys.

CrewAI

from agentguard.adapters.crewai import guard_crew_tools

guarded_tools = guard_crew_tools(
    tools=my_crew_tools,
    guard_url="http://localhost:8080",
    agent_id="crew-agent",
)

Hooks both run and _run (CrewAI calls _run internally).

browser-use

from agentguard.adapters.browseruse import GuardedBrowser

browser = GuardedBrowser(guard_url="http://localhost:8080")

if browser.check_navigation("https://example.com").allowed:
    await page.goto("https://example.com")

# Or wrap the page directly so goto() enforces policy for you:
guarded_page = browser.wrap_page(page)
await guarded_page.goto("https://example.com")   # raises PermissionError on deny/approval

MCP

from agentguard.adapters.mcp import GuardedMCPServer

server = GuardedMCPServer(guard_url="http://localhost:8080")
server.add_tool("my_tool", "Description", handler=my_handler)
server.run()   # stdio JSON-RPC MCP server; pins MCP_PROTOCOL_VERSION

Or as a drop-in stdio server:

python -m agentguard.adapters.mcp --guard-url http://localhost:8080

API reference (summary)

Guard(base_url="", agent_id="", timeout=5, api_key="", fail_mode="deny")

CheckResult

Fields: decision, reason, matched_rule, approval_id, approval_url. Properties: .allowed, .denied, .needs_approval.

Exception hierarchy (all extend PermissionError)

• AgentGuardError — base; carries .result: CheckResult.
• AgentGuardDenied — policy said DENY.
• AgentGuardApprovalRequired — policy said REQUIRE_APPROVAL and the decorator was not configured to wait. Carries .approval_id, .approval_url.
• AgentGuardApprovalTimeout — wait_for_approval deadline elapsed. Carries .approval_id.

License

Apache 2.0