Overview (Transports) - MCP specification revision 2026-07-28

Publisher

Model Context Protocol project

URL

https://modelcontextprotocol.io/specification/2026-07-28/basic/transports

Published

2026-07-28

Updated

unknown

Accessed

2026-09-30

HTTP status

200

License

not stated on the page; not verified; no-redistribution; short excerpts and locators only

Source notes citing this source

• In MCP revision 2026-07-28 all protocol metadata travels in the message body under _meta io.modelcontextprotocol/* fields; a binding MAY additionally mirror selected body fields into envelope metadata, but the body remains the source of truth. in context
• In MCP revision 2026-07-28 custom transports MUST preserve the JSON-RPC message format, the message patterns and the per-request metadata model, and custom transports that run over a reliable bidirectional byte stream such as Unix domain sockets or TCP SHOULD reuse the stdio framing. in context
• In MCP revision 2026-07-28 a transport binding MUST deliver client-sent requests and notifications to the server and server-sent responses and notifications to the client; no other message direction exists, so servers do not initiate JSON-RPC requests and clients do not send JSON-RPC responses. in context
• In MCP revision 2026-07-28 protocol semantics are identical on every transport; a transport is a binding that defines only message framing and delivery, how request metadata is carried, and how cancellation and termination are signalled. in context
• MCP revision 2026-07-28 appears to no longer recommend that clients support stdio whenever possible: the sentence is absent from the 2026-07-28 transports overview and stdio pages as retrieved. inferred in context
• MCP revision 2026-07-28 specifies two standard transport bindings, stdio and Streamable HTTP, and also permits custom transports. in context
• MCP JSON-RPC messages MUST be UTF-8 encoded regardless of transport. in context

Cite this source record

APA

WarmTransfer. (2026, July 28). Overview (Transports) - MCP specification revision 2026-07-28. WarmTransfer. https://warmtransfer.net/knowledge/sources/mcp-spec-2026-07-28-transports

BibTeX

@misc{warmtransfer-mcp-spec-2026-07-28-transports,
  title  = {Overview (Transports) - MCP specification revision 2026-07-28},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/mcp-spec-2026-07-28-transports},
  note   = {Model Context Protocol project, accessed 2026-09-30}
}