MCP Integration

Helm exposes an MCP server for agents.

The MCP server does not hold agent private keys. It helps the agent build and submit signed payment requests to Helm.

Flow

1. User gives the agent scoped access in Helm.
2. Agent keeps its own key locally.
3. Agent asks MCP to build a payment request.
4. Agent signs the message locally.
5. Agent submits the signed request through MCP.
6. If Helm approves it, the agent submits the Tempo transaction.
7. Agent records the transaction with Helm.

Tools

The MCP server exposes tools for:

• reading wallet and Tempo configuration
• building a payment request
• submitting a signed payment request
• checking request status
• recording a completed payment

Signing model

The agent signs requests with the same key that the user approved in Helm.

Helm verifies the signature against the saved agent key address. The backend does not receive the private key.

Expiry and nonce

Every request needs:

• a fresh nonce
• a short expiry
• exact token, recipient, and amount

Helm rejects requests with expiry longer than one hour. Helm also rejects a nonce if it was already used for different payment details.