Helio MCP server

Helio Open-source governance for MCP agents: useful autonomy without unlimited authority.

Getting Started · Docs · Contributing

Helio is an MCP proxy that sits between your AI agents and the tools they use. Every tool call passes through Helio, which enforces policies, requires prerequisites, checks evidence, routes approvals, caps cumulative spend, and records everything - without changing your agent code or your MCP servers.

The 2026-07-28 MCP revision made the protocol itself stateless: no handshake, no protocol-level sessions, cross-call state carried as handles the model passes between tools. That pattern works for application state and fails for governance state, because a budget key the model can see is a budget key the model can change. Helio keeps session identity, budgets, and evidence in the proxy, outside the agent's context, which is why those controls still mean something after the protocol stopped tracking sessions. See stateless protocol, stateful governance.

npx @gethelio/proxy init

@gethelio/proxy is the only Node package you install. It ships the proxy runtime and bundled dashboard UI assets together.

ALLOW      read_customer
APPROVE    refund > £50
DENY       production.delete
BUDGET     £500/day across matching paid tools
REQUIRE    order.lookup succeeded before refund

Why Helio?

Your agent just called an API you didn't expect. It spent money you didn't authorize. It modified a production record you can't easily undo.

Model providers are building governance for their own platforms but your agents run across Claude, ChatGPT, LangChain, CrewAI, and custom frameworks. No single platform governs the full picture. And none of them govern what happens in downstream systems like Stripe, Salesforce, or GitHub.

Helio governs what agents do to the rest of the world across any MCP-compatible agent, any tool, any platform.

Shortened. The full README is on GitHub.