---
title: "Open an MCP server-to-client SSE stream"
method: GET
path: "/v1/mcp"
tags: ["mcp"]
---

# Open an MCP server-to-client SSE stream

`GET /v1/mcp`

Open a long-lived server-to-client SSE stream for the current MCP session as defined by the Streamable HTTP transport. The `Mcp-Session-Id` header must identify an existing session created via `POST /v1/mcp`.

## Response `200`

SSE stream (`text/event-stream`) of server-originated MCP messages.

## Other responses

- `401` — Unauthorized. The `/v1/mcp` endpoint requires `runtime.auth` to be configured. Configure an API key provider in your Spicepod and retry with credentials.
- `403` — Forbidden. The `Host` header value is not in the `runtime.mcp.allowed_hosts` list.
- `404` — Unknown or expired `Mcp-Session-Id`.

## Changes

- **2026-05-07** `f6728b372006` — 2 info
  - added the non-success response with the status `401`
  - added the non-success response with the status `403`
- **2026-05-04** `6e68f5c91efd` — 1 info
  - endpoint added
- **2025-03-18** `dd94571fef79` — 1 breaking
  - api path removed without deprecation

[Change history](https://skmtc.dev/spiceai/apis/runtime/changes/v1/mcp/get.md)

---

[API](https://skmtc.dev/spiceai/apis/runtime.md) · [All operations](https://skmtc.dev/spiceai/apis/runtime/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/spiceai/runtime/revisions/f4bb5537fc13/schema)