MCP protocol version header handling fixes
Cluster 53676 · mcp. Data as of
Nothing open on GitHub. Fix merged in #106432 on 13 Sep 2026. Check it covers your case.
The short answer
- Known?
- Yes. 3 related items grouped here, 1 issue already closed.
- Fix event
- A fix was merged to main in PR #106432. Check it covers your case. No release data is tracked.
- Tracker
- The maintainers' tracker marks this
resolved, deciding PR #106432. That is separate from the fix event. - Still open
- Nothing open on GitHub.
Multiple issues and fixes related to the incorrect injection of the mcp-protocol-version header on the MCP initialize request, which violates the MCP spec and causes initialization failures with certain servers. Fixes also address SSE transport fallback behavior.
Open issues0
Open PRs0
Fixes on record
-
#106432 fix(mcp): SSE-only MCP servers now connect via automatic transport fallback (salvage #53764)
files:
tests/tools/test_mcp_sse_fallback.py,tools/mcp_tool.py,tools/mcp_tool_errors.py,tools/mcp_tool_transport.py
1 PR closed without merging
From the close comments: merged via another change 1
-
#53764 fix(mcp): auto-fallback to SSE transport when Streamable HTTP returns…400 · merged via another change →
a565e2d,#106432
Closed issues · 1
- Closed#53676[Bug]: MCP HTTP transport: wigai server fails to initialize, ends as 0 active MCP servers
How this cluster was grouped
-
Link evidence (
structural links throughout): every member is connected by structural evidence: shared changed files, or a closing/superseded reference. -
Pairwise link density
0.67: the share of item pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36.1.00means every pair is linked.
Pick up a Lab task
Check whether a fix covers the open issues here, with your own agent. Bring back evidence for maintainers.
Open the LabAt a glance
- Subsystem
- mcp
- Merged PRs
- #106432
- Closed issues
- 1
- Attempts
- 1 PR closed without merging
- Fix link checked
- 13 Sep 2026