---
search:
  tags:
    - MCP
    - POST
seo:
  description: >-
    Verified human Clerk sessions or agent OAuth tokens with exact MCP resource
    audience.… Reference for the POST /mcp endpoint in the agentsub Gateway API.
sidebar:
  label: Model Context Protocol HTTP endpoint
  badge: POST
title: Model Context Protocol HTTP endpoint
type: openapi-operation
---
Verified human Clerk sessions or agent OAuth tokens with exact MCP resource audience. Stateless MCP supports July 2026 per-request envelopes and legacy November 2025 POST compatibility. Authorization is verified before tool discovery; individual tools retain human/agent/scope restrictions.

`POST /mcp`

**Responses**

- `200` — MCP protocol response (JSON or SSE stream)
- `401` — \`unauthorized\` problem; live 401s advertise \`WWW-Authenticate: Bearer resource\_metadata=...\`
- `403` — Identity, ownership, scope or policy denied (\`human\_required\`, \`owner\_claim\_required\`, \`scope\_required\`, \`FROZEN\`, \`CAP\_EXCEEDED\`, \`SCOPE\_FORBIDDEN\`)
- `503` — Runtime or provider configuration unavailable (\`runtime\_configuration\_required\`, \`signing\_configuration\_required\`, \`runtime\_unavailable\`, \`workspace\_unavailable\`, \`provider\_configuration\_required\`)