Modern Treasury MCP Server

Modern Treasury is a payment operations platform for moving money over ACH, wire, RTP and other rails, with ledgering and reconciliation on top. Its official MCP server gives an AI agent access to that API — but it is worth understanding how, because the design is unusual.

Code Mode instead of one tool per endpoint. Most API-backed MCP servers enumerate their endpoints as individual tools, which floods an agent's context and still leaves it stitching results together by hand. This server exposes just two tools: a documentation search tool for querying the API and SDK docs, and a code tool where the agent writes TypeScript against the Modern Treasury SDK. The code runs in an isolated sandbox with no web or filesystem access, and whatever it returns or prints comes back as the tool result.

The practical effect is that multi-step work stays in one call. Listing counterparties, filtering them, creating payment orders for a subset and summarising the outcome is a single script the agent writes, rather than a dozen round-trips through separate tools — which is both cheaper in context and more deterministic to repeat.

Configuration. Three environment variables: MODERN_TREASURY_API_KEY, MODERN_TREASURY_ORGANIZATION_ID and MODERN_TREASURY_WEBHOOK_KEY. Installs through npx for any MCP client, with published one-click links for Cursor and VS Code and a claude mcp add command for Claude Code. A remote-hosted mode is also documented.

Maintained inside the official modern-treasury-node SDK repository, so it versions in lockstep with the TypeScript SDK it drives. MIT licensed.

A note on scope. This is a production payments API. Point it at a sandbox organisation before you let an agent write against it, and scope the API key to the minimum the task needs — the code tool can call anything the key can.