Return 202 Accepted for SSE responses per MCP spec#245
Open
koic wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
Return 202 Accepted for SSE responses per MCP spec#245koic wants to merge 1 commit intomodelcontextprotocol:mainfrom
koic wants to merge 1 commit intomodelcontextprotocol:mainfrom
Conversation
`StreamableHTTPTransport#send_response_to_stream` returned 200 with
`{ accepted: true }` body, but the MCP spec requires 202 with empty body
when a response is sent via SSE stream. This has been a requirement since
Streamable HTTP was introduced in protocol version 2025-03-26.
- https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#sending-messages-to-the-server
- https://modelcontextprotocol.io/specification/2025-11-25/basic/transports#sending-messages-to-the-server
koic
force-pushed
the
fix_sse_response_status
branch
from
389c4bb to
a02a457
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Motivation and Context
StreamableHTTPTransport#send_response_to_streamreturned 200 with{ accepted: true }body, but the MCP spec requires 202 with empty body when a response is sent via SSE stream. This has been a requirement since Streamable HTTP was introduced in protocol version 2025-03-26.How Has This Been Tested?
Added a repro test to verify the fix and prevent regression.
Breaking Changes
None. This fixes behavior that was incorrect with respect to the specification.
Types of changes
Checklist