What is the Model Context Protocol (MCP)?
MCP is an open JSON-RPC 2.0 protocol that lets large language model agents discover and call external tools through a single standardised endpoint, removing the need for per-vendor SDKs.
The Model Context Protocol standardises how LLM-based agents (Claude, ChatGPT desktop, Cursor, custom SDKs) talk to external tools. Each tool is described by a JSON Schema, dispatch is JSON-RPC 2.0, and any compliant client can use any compliant server without bespoke integration code.
On Sella, the entire agent surface is exposed at one endpoint (POST /api/mcp), organized into tool families: discovery (one unified catalogue search across datasets, APIs, workflows, and native products), transaction (dataset purchase and the Cradle/Mergekit GPU job lifecycle), commerce actions (reviews, flags, activity, job polling), and policy (spend caps, purchase preview, decision receipts, and human-approval escalation).