fix: filter CLAUDECODE from subprocess environment#594
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gspeter-max wants to merge 1 commit intoanthropics:mainfrom
Open
fix: filter CLAUDECODE from subprocess environment#594gspeter-max wants to merge 1 commit intoanthropics:mainfrom
gspeter-max wants to merge 1 commit intoanthropics:mainfrom
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ROOT CAUSE: CLAUDECODE=1 environment variable leaks into child subprocess when SDK is used from within Claude Code (hooks, plugins, subagents). Child CLI detects this and rejects the session thinking it's a nested session. CHANGES: - Filter CLAUDECODE from parent environment before merging in SubprocessCLITransport.connect() - This prevents false nesting detection while allowing users to explicitly set CLAUDECODE via env option if needed - Add test_claudecode_env_var_is_filtered to verify CLAUDECODE is filtered - Add test_claudecode_can_be_explicitly_set to verify user override capability IMPACT: - Enables SDK usage from within Claude Code sessions (hooks, plugins, subagents) - Fixes primary use case for the SDK - Unblocks hook-based workflows (guardrails, prompt injection detection, etc.) TECHNICAL NOTES: - CLAUDECODE=1 is a safety check in Claude Code CLI to prevent actual nesting - SDK subprocesses are isolated and safe, but the variable causes false positive - Implementation filters CLAUDECODE from os.environ before merge - Users can still override via env option (self._options.env takes precedence) - Approach C chosen: filter before merge for clarity and flexibility FILES MODIFIED: - src/claude_agent_sdk/_internal/transport/subprocess_cli.py - tests/test_transport.py Fixes anthropics#573 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Fixes #573
Root Cause
CLAUDECODE=1 environment variable leaks into child subprocess when SDK is used from within Claude Code (hooks, plugins, subagents). Child CLI detects this and rejects the session thinking it's a nested session.
Changes
SubprocessCLITransport.connect()envoption if neededtest_claudecode_env_var_is_filteredto verify CLAUDECODE is filteredtest_claudecode_can_be_explicitly_setto verify user override capabilityImpact
Technical Notes
os.environbefore mergeenvoption (user-provided env takes precedence)Testing
test_claudecode_env_var_is_filteredtest_claudecode_can_be_explicitly_setCo-Authored-By: Claude Sonnet 4.6 noreply@anthropic.com