fix: keep stdin open for hooks during multi-turn agent execution#580
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pjcdawkins wants to merge 1 commit intoanthropics:mainfrom
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fix: keep stdin open for hooks during multi-turn agent execution#580pjcdawkins wants to merge 1 commit intoanthropics:mainfrom
pjcdawkins wants to merge 1 commit intoanthropics:mainfrom
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stream_input() previously closed stdin after receiving the first result message, which broke hook callbacks (permission checks, security filtering, cancellation) on all subsequent agent turns. The CLI's sendRequest() threw "Stream closed" errors on every tool call. Now, when hooks or SDK MCP servers are configured, stream_input() blocks indefinitely instead of closing stdin. The task group cancellation in close() handles cleanup, and transport.close() closes stdin. Also removes the unused _first_result_event and _stream_close_timeout members that supported the old behavior. Fixes anthropics#554 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
stream_input()closes stdin after receiving the firstresultmessage. In multi-turn agents (max_turns > 1), this breaks hook callbacks on all subsequent turns because the bidirectional control channel is gone. The CLI'ssendRequest()throws"Stream closed"on every tool call after the first turn.This PR changes
stream_input()to block indefinitely (viaanyio.sleep_forever()) when hooks or SDK MCP servers are configured, keeping stdin open for the entire session. Cleanup is handled by the existingclose()path: the task group cancellation breaks the sleep, andtransport.close()closes stdin.end_input()called immediately)Also removes the now-unused
_first_result_eventand_stream_close_timeoutmembers.Fixes #554
Test plan
stream_inputcallsend_input()without hooksstream_inputblocks (does not callend_input()) with hooks🤖 Generated with Claude Code