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Timeout on client if MCP server doesnt support event-stream

bugSomething isn't workingSomething isn't working

needs reproneeds additional information to be able to reproduce bugneeds additional information to be able to reproduce bug

Status: Open.

#1403 In modelcontextprotocol/python-sdk;

· ShadyRoll opened on Sep 25, 2025

streamable_http client call_tool hangs when receiving invalid JSONRPCMessage

bugSomething isn't workingSomething isn't working

P1Significant bug affecting many users, highly requested featureSignificant bug affecting many users, highly requested feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#1144 In modelcontextprotocol/python-sdk;

· Nuclear2 opened on Jul 15, 2025

Race Condition in StreamableHTTP Transport Causes ClosedResourceError

bugSomething isn't workingSomething isn't working

P0Broken core functionality, security issues, critical missing featureBroken core functionality, security issues, critical missing feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#1363 In modelcontextprotocol/python-sdk;

· Edison-A-N opened on Sep 13, 2025

MCP server in the HTTP Streamable mode broken

bugSomething isn't workingSomething isn't working

P1Significant bug affecting many users, highly requested featureSignificant bug affecting many users, highly requested feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#1190 In modelcontextprotocol/python-sdk;

· akolotov opened on Jul 23, 2025

Cannot break out of session.initialize() when using streamable-http

bugSomething isn't workingSomething isn't working

needs reproneeds additional information to be able to reproduce bugneeds additional information to be able to reproduce bug

Status: Open.

#874 In modelcontextprotocol/python-sdk;

· efcwetgw opened on Jun 3, 2025

Streamable HTTP client performance regression starting with v1.12.0

bugSomething isn't workingSomething isn't working

P2Moderate issues affecting some users, edge cases, potentially valuable featureModerate issues affecting some users, edge cases, potentially valuable feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#1274 In modelcontextprotocol/python-sdk;

· rcxwhiz opened on Aug 14, 2025

AssertionError: Unexpected message while using middlewares

bugSomething isn't workingSomething isn't working

P1Significant bug affecting many users, highly requested featureSignificant bug affecting many users, highly requested feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#883 In modelcontextprotocol/python-sdk;

· toughnoah opened on Jun 4, 2025

Errors with Streamble HTTP

bugSomething isn't workingSomething isn't working

needs confirmationNeeds confirmation that the PR is actually required or needed.Needs confirmation that the PR is actually required or needed.

Status: Open.

#1072 In modelcontextprotocol/python-sdk;

· pavankay opened on Jul 3, 2025

context.report_progress not sending notifications on streamable-http

bugSomething isn't workingSomething isn't working

P3Nice to haves, rare edge casesNice to haves, rare edge cases

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#953 In modelcontextprotocol/python-sdk;

· abdhx opened on Jun 13, 2025

Issue: Custom HTTP Headers (e.g., mcp-session-id) Not Received by FastMCP Server

bugSomething isn't workingSomething isn't working

P2Moderate issues affecting some users, edge cases, potentially valuable featureModerate issues affecting some users, edge cases, potentially valuable feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#1063 In modelcontextprotocol/python-sdk;

· hileamlakB opened on Jun 30, 2025

sse_app() ignores mount prefix, resulting in 404 from client

bugSomething isn't workingSomething isn't working

P2Moderate issues affecting some users, edge cases, potentially valuable featureModerate issues affecting some users, edge cases, potentially valuable feature

ready for workEnough information for someone to start working onEnough information for someone to start working on

Status: Open.

#412 In modelcontextprotocol/python-sdk;

· allieus opened on Apr 2, 2025