fix: enforce retry limit when SSE stream makes no progress#742
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maciej-kisiel merged 4 commits intomodelcontextprotocol:mainfrom Feb 3, 2026
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…extprotocol#679) Previously, the StreamableClientTransport retry counter would reset whenever a connection was re-established, which could lead to infinite retry loops if a server continuously terminates connections without making progress (advancing the Last-Event-ID). This change tracks progress across retry attempts in handleSSE: - The retry counter is only reset when the Last-Event-ID advances - If maxRetries is exceeded without progress, the connection fails - This implements Option 2 from the issue discussion 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> Signed-off-by: majiayu000 <1835304752@qq.com>
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Thanks for this contribution, and sorry for the delay. I'll be catching up on PRs this weekend / next week. |
findleyr
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Jan 3, 2026
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Thanks, this looks good. Just a couple nits in the test.
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| // Verify that we actually retried the expected number of times. | ||
| // We expect maxRetries+1 attempts because we increment before checking the limit. |
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In this case, make this more assertive: assert that got == maxRetries+1
mcp/streamable_client_test.go
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const maxRetries = 2
(more readable, and avoids some conversions below)
scutuatua-crypto
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Jan 10, 2026
maciej-kisiel
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Jan 29, 2026
maciej-kisiel
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Jan 29, 2026
findleyr
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Feb 3, 2026
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Thanks! @maciej-kisiel feel free to merge.
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Fixes #679
Changes
This implements Option 2 from the issue: progress-based retry limiting that prevents infinite retry loops while allowing long-running streams to continue as long as progress is made.