MCP Payments

Connect agents to prepaid, metered tools through Model Context Protocol (MCP) with OAuth or enterprise service credentials scoped to a bundle of tools.

What is the Model Context Protocol?

The Model Context Protocol (MCP), created by Anthropic, is an open standard that lets AI applications discover and call external tools through a common interface. Locus Pro exposes one hosted MCP server for metered catalog tools, so a client can search, inspect, estimate, and execute permitted APIs without configuring a separate provider key for each one.

How Locus integrates with MCP

Locus MCP server

Locus Pro provides a hosted MCP server backed by 3,786 catalog services and 15,968 callable endpoints. Its compact meta-tools let an agent search the catalog, inspect one contract, estimate cost, and execute an allowed tool.

Automatic payment on tool call

When the agent invokes a tool, Locus Pro reserves and burns prepaid credits from the authenticated account. Available balance, enabled tools, credential scope, and any enterprise end-user or connection limits are checked before provider execution.

OAuth for people, scoped credentials for services

Use an OAuth-capable MCP client for an interactive personal or enterprise connection. An unattended enterprise runtime can send a scoped lcac_ Agent Connection credential if its client supports custom authorization headers. Tenant secret keys stay on trusted servers.

MCP payment workflow

Here's what happens when an agent makes a paid MCP tool call:

•Tool discovery — The client receives compact catalog meta-tools, then uses search_apis and describe_api to retrieve only permitted contracts and their price or pricing basis.
•Tool invocation — An interactive client completes browser OAuth. A headless enterprise client sends its endpoint- and budget-scoped lcac_ credential. Neither flow puts a tenant secret key in the MCP client.
•Policy check — Locus verifies that the prepaid credit balance can cover the quote and that the call satisfies enabled-tool, credential, account, and configured policy limits.
•Execution and billing — Locus calls the selected API, returns the result with charged credits and remaining balance, and records the burn for usage review. MCP calls are non-streaming; a failed upstream call releases its reservation.

Why MCP payments matter

MCP standardizes tool discovery and invocation, but it does not define prepaid balances, per-call metering, refunds, or enterprise account policy. Locus Pro adds those controls behind one hosted server, letting agents use premium catalog tools while account owners keep a bounded balance, explicit access, and a durable usage record.

Related resources

Connect via MCP MCP integration guide