Fix: Move markInitialized() and reconnect() after status code check#774
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irwin-chequer wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
Fix: Move markInitialized() and reconnect() after status code check#774irwin-chequer wants to merge 1 commit intomodelcontextprotocol:mainfrom
irwin-chequer wants to merge 1 commit intomodelcontextprotocol:mainfrom
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When connecting to an MCP server that doesn't support Streamable HTTP transport (returns 405 Method Not Allowed), the transports still called markInitialized() and reconnect() before checking the status code, which triggered unnecessary GET requests. This caused issues when using transport fallback (Streamable HTTP → SSE), as duplicate SSE sessions were created on the upstream server. This fix moves markInitialized() and reconnect() inside the success status code check (2xx), so they are only called for successful responses. Fixes modelcontextprotocol#773 Related to modelcontextprotocol#362 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Summary
markInitialized()andreconnect()were called before checking the HTTP status codeHttpClientStreamableHttpTransportandWebClientStreamableHttpTransportare fixedProblem
When connecting to an MCP server that doesn't support Streamable HTTP transport (returns 405), the transports still called
markInitialized()andreconnect(), triggering unnecessary GET requests. This caused duplicate SSE sessions on the upstream server when using transport fallback.Solution
Move
markInitialized()andreconnect()inside the success status code check (2xx), so they are only called for successful responses.Test plan
Fixes #773
Related to #362
🤖 Generated with Claude Code