Send MCP-Protocol-Version header in Streamable HTTP client transport #500
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stephentoub
reviewed
Jun 10, 2025
| { | ||
| if (sessionId is not null) | ||
| { | ||
| headers.Add("mcp-session-id", sessionId); | ||
| } | ||
|
|
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| if (protocolVersion is not null) | ||
| { | ||
| headers.Add("mcp-protocol-version", protocolVersion); |
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Is all lower case correct? I understand header names are case insensitive, but the spec clearly spells it out as MCP-Protocol-Version. Shouldn't we use the same casing?
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I agree that we should be writing out the header in a casing that is consistent with the specification.
stephentoub
approved these changes
Jun 10, 2025
| { | ||
| if (!StringValues.IsNullOrEmpty(context.Request.Headers["mcp-session-id"])) | ||
| { | ||
| protocolVersionHeaderValues.Add(context.Request.Headers["mcp-protocol-version"]); |
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Consider factoring this and other header names into a constant for DRY purposes.
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modelcontextprotocol/modelcontextprotocol#548 updated the MCP specification to require the following:
This updates the client Streamable HTTP transport to send this header.
Replaces #493