MCP vs API
Same engine. Different way of asking.
MCP is the protocol surface for AI agents. REST is the direct surface for applications. Both use one HumanDesign.ai API key and shared plan limits.
| Question | MCP | REST API |
|---|---|---|
| Who chooses the operation? | The AI client discovers and selects a tool. | Your application calls an explicit route. |
| Surface | One /mcp JSON-RPC endpoint. | A complete catalog of HTTP endpoints. |
| Best for | Claude, Codex, Cursor, VS Code, and custom agents. | Web apps, mobile apps, automations, data pipelines. |
| Coverage | Six structured tools. | Charts, forecasts, returns, calendars, webhooks, batch, and more. |
| Billing | Successful tool calls use shared API units. | Billed requests use the same shared API units. |
Choose MCP when…
An agent should inspect schemas, choose among allowed tools, and call them inside a conversational workflow.
Connect MCPChoose REST when…
Your code already knows the calculation it needs, or you need the broader endpoint catalog.
Explore REST