Model Context Protocol
2026-10-234 minexplanationWIP
MCP is an open standard for connecting AI assistants to external tools and data sources. Poly speaks it: platform features — the secrets vault today, more over time — can be exposed to any MCP-compatible client.
How MCP works
MCP uses JSON-RPC 2.0. A server exposes three primitives:
| Primitive | Description | Example |
|---|---|---|
| Tools | Actions the AI can perform | list vaults, fetch a secret |
| Resources | Read-only data sources | a vault listing, an env export |
| Prompts | Pre-built prompt templates | a setup walkthrough |
The client discovers what a server offers, then calls it on the model's behalf — the model sees tool descriptions and results, never raw credentials.
Where Poly uses MCP
- Secrets — the vault is MCP-accessible inside Poly, governed by the activity log and leases. See Secrets & MCP.
- Assistants — direct connections from Claude Code and Cursor are being wired up: Claude Code, Cursor.
Learning more
The protocol reference covers the JSON-RPC message shapes; configuration covers how a client is pointed at a server.