fix(stdio): allow configurable memory-stream buffer size#2163
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giulio-leone wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
fix(stdio): allow configurable memory-stream buffer size#2163giulio-leone wants to merge 1 commit intomodelcontextprotocol:mainfrom
giulio-leone wants to merge 1 commit intomodelcontextprotocol:mainfrom
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Add read_stream_buffer_size and write_stream_buffer_size parameters to stdio_server() so callers can increase the internal memory-object-stream capacity. The default (0 = synchronous hand-off) is preserved for backward compatibility. With max_buffer_size=0 the stdin reader blocks whenever the message processor is busy, making the server unresponsive to pings and new requests during slow operations. A small buffer (e.g. 8) decouples reading from processing and lets the server remain responsive. Closes modelcontextprotocol#1333 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Problem
stdio_server()hardcodesmax_buffer_size=0for both internal memory object streams, creating synchronous hand-off between the stdin reader and the message processor. When the processor is busy with a slow operation (DB query, API call, file I/O), the stdin reader blocks and the server becomes completely unresponsive to pings and new requests.Reported in #1333 — a server became unresponsive after 67 minutes of operation with requests every 10 seconds.
Solution
Add two optional parameters to
stdio_server():read_stream_buffer_size0write_stream_buffer_size0Defaults preserve current behaviour. Callers who need responsiveness under load can set a small buffer (e.g.
8) to decouple reading from processing.Testing
Existing
test_stdio_serverpasses — the default values keep behaviour identical.Closes #1333