Source note · Model Context Protocol transports compared
In Streamable HTTP under MCP revision 2026-07-28, a server that does not implement the requested RPC method MUST respond with 404 Not Found and a JSON-RPC error with code -32601, and a server that does not implement the requested protocol version MUST respond with 400 Bad Request and an UnsupportedProtocolVersionError listing its supported versions.
Checked 2026-09-30
- Vendor
- Model Context Protocol project
- Product
- MCP specification
- Subsystem
- Streamable HTTP transport
- Deployment
- remote-http
- Region
- not restricted
- Release range
- MCP revision 2026-07-28
- Checked
- 2026-09-30
Sources
- Model Context Protocol specification 2026-07-28, Streamable HTTP — Model Context Protocol project · tier 1 standards and regulators · section Request Metadata, subsection Protocol Version Header, fourth and fifth paragraphs
Cite this note
APA
WarmTransfer. (2026, September 30). Model Context Protocol transports compared: source note mcp-transport-differences-http-method-not-found-404. WarmTransfer. https://warmtransfer.net/knowledge/claims/mcp-transport-differences-http-method-not-found-404
BibTeX
@misc{warmtransfer-claim-mcp-transport-differences-http-method-not-found-404,
title = {Model Context Protocol transports compared: source note mcp-transport-differences-http-method-not-found-404},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/mcp-transport-differences-http-method-not-found-404},
note = {Source note mcp-transport-differences-http-method-not-found-404, checked 2026-09-30}
}