MCP Specification 2026-07-28 Removes Sessions and the Mcp-Session-Id Header
Sep 21, 202610 min0 plays
The question this episode answers
If MCP removes sessions and the Mcp-Session-Id header, which parts of an existing MCP deployment will actually break, and what evidence should an engineering team require before switching to the stateless protocol core?
Audit MCP clients, servers, proxies, and authorization middleware before adopting the stateless protocol core, because implementations that depend on initialize/initialized handshakes or connection-scoped state can fail during migration. ([github.com](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/blog/content/posts/2026-07-28-spec-ga/index.md))
Researched & cited
Every claim is researched from multiple sources and cross-checked before narration. Daycast is made with AI — researched, written, and narrated — and we say so in every episode. Sources below.
- modelcontextprotocol/blog/content/posts/2026-07-28-spec-ga/index.md at main · modelcontextprotocol/modelcontextprotocol · GitHub
- modelcontextprotocol/seps/2567-sessionless-mcp.md at main · modelcontextprotocol/modelcontextprotocol · GitHub
- modelcontextprotocol/docs/specification/2025-11-25/basic/transports.mdx at main · modelcontextprotocol/modelcontextprotocol · GitHub
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