Streamable HTTP is not defined by the earliest supported MCP protocol version. Scope the transport to versions that define it and keep root protocol coverage consistent. A URL alone does not make a transport applicable to every protocol version.
Requirement
Section titled “Requirement”Streamable HTTP is used only from MCP 2025-03-26.
Details
Section titled “Details”Rule ID: mcp.transport.streamable-http.protocol-version
Owner: mcp
Surface: Transport
Kind: structural
Requirement level: must
Status: internal · Enforcement: internal
Protocol version applicability
Section titled “Protocol version applicability”2024-11-05 |
2025-03-26 |
2025-06-18 |
2025-11-25 |
2026-07-28 |
|---|---|---|---|---|
| applies | applies | applies | applies | applies |
Required by
Section titled “Required by”- MCP Description 0.9.0, Section 6.2
- 6. Transports: req-transport-streamable-http-protocol-versions
Based on
Section titled “Based on”- Tier 1 — MCP schema.ts and normative specification text: MCP 2025-03-26 specification, Basic, Transports, Streamable HTTP (replaces HTTP+SSE from 2024-11-05)
Examples
Section titled “Examples”Invalid example
Section titled “Invalid example”Source: expected-invalid/protocol-version-inapplicable-streamable-http.json · Selected: /transports/0
{ "type": "streamable-http", "url": "https://example.com/mcp"}Rule Source Code
Section titled “Rule Source Code”transport.yaml at immutable tag v0.9.0-rc.3.