Phinq

Open-source guardrail that intercepts AI agent tool calls and requires human approval for risky actions.

Verified API available Free tier
Quick facts
What is it Open-source guardrail that intercepts AI agent tool calls and requires human approval for risky actions.
Pricing Free
Free tier Yes
Platform API
API Yes
Best for Preventing unintended actions by AI agents, Implementing human-in-the-loop for critical AI operations
Domain registered 2025

Data updated Aug. 15, 2026

What does Phinq do?

Phinq is an open-source runtime governance layer for AI agents. It sits between an agent and the tools it calls, intercepting every tool call before execution. Each action is classified by risk: safe, reversible actions pass through automatically; risky or irreversible ones — deleting records, reading credentials, sending payments — are held for human approval. If no one responds in time, the action is blocked. It fails closed.

The enforcement is structural, not advisory. A prompt can be ignored; an API-boundary intercept can't. You can run Phinq as a proxy, an in-process SDK, or a plain HTTP gate, so it works with agents that speak OpenAI, Anthropic, or Gemini APIs, including Claude Code, Codex, Gemini CLI, LangChain, CrewAI, Mastra, and MCP. Every decision — passed, held, approved, denied — goes into a hash-chained, append-only audit log. Each entry includes the hash of the one before it, so tampering is detectable. The project is MIT licensed and available on GitHub.

Who is this for? Teams running AI agents that touch sensitive or destructive actions — internal automation, customer-facing products, anything where an agent could act while no one is watching. Phinq gives them a real decision point before damage and a verifiable record afterward. Hosted policy controls and team workflows are future features; the open-source layer is available today.

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Key features

What makes it stand out
01
Intercepts every agent tool call before execution, so nothing dangerous happens silently
02
Holds irreversible actions like deletes, credential reads, payments, or bulk sends until a human approves
03
Fails closed: timed-out or denied approvals block the action
04
Writes every decision to a tamper-evident, hash-chained audit log
05
Runs as proxy, SDK, or HTTP gate, compatible with OpenAI, Anthropic, Gemini, and MCP-based agents

Who is Phinq for?

Who benefits most from this tool
Preventing unintended actions by AI agents
Implementing human-in-the-loop for critical AI operations
Auditing AI agent behavior for compliance and security

Trust & presence

Domain Domain registered 2025

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