integrate-arcjet-guard-crewai

Integrate Arcjet Guard into CrewAI

arcjet.guard.crewai wraps the agent's existing Arcjet client. It never talks to the Arcjet API itself. Shared Guard fundamentals (client, rules, labels, decisions, capture, registration) live in ../arcjet/references/guards_python.md. Load that reference for anything that is not CrewAI-specific.

Official crewai only — not community forks, not LangChain Crew wrappers, not an npm CrewAI port. There is no arcjet[crewai] extra: CrewAI hard-depends on chromadb, which carries unpatched RCE CVE-2026-45829, so an Arcjet extra must not pull it in. Install CrewAI yourself. Importing arcjet.guard.crewai does not load LangChain.

Exports: register_arcjet_hooks, unregister_arcjet_hooks, ArcjetCrewAIHooks, guard_tool, ToolPolicy, sanitize_tool_name, free_text_arguments. There is no guard_crew.

Two surfaces, one decision rule:

• A tool a crew, LiteAgent, MCP adapter, or crew-injected list executes → register_arcjet_hooks + ToolPolicy. Gate is process-wide PRE_TOOL_CALL only. DENY raises HookAborted(reason=..., source="arcjet").
• A CrewAI BaseTool you call yourself → guard_tool. This is the only CrewAI path that raises ArcjetDeniedError / ArcjetUnavailableError. BaseTool.run never dispatches PRE_TOOL_CALL.

Docs: https://docs.arcjet.com/guards/crewai/.

The gate is process-wide PRE_TOOL_CALL, once

register_arcjet_hooks registers on CrewAI's dispatcher. A DENY (or unevaluated Guard under the default on_guard_error="deny") raises HookAborted(reason=..., source="arcjet") so the tool never runs. CrewAI swallows every other exception — raising ArcjetDeniedError / ArcjetUnavailableError from the hook would run the tool. The hook path is sync only — pass launch_arcjet_sync / ArcjetGuardSync. An async client is refused at registration (ArcjetMisconfiguration). A second register_arcjet_hooks in the same process is also ArcjetMisconfiguration (CrewAI's registry appends and would double-evaluate); call unregister() on the handle first.