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fix: restore stdin redirect for Claude sandbox #41

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Merged
nikhilwoodruff merged 1 commit into from
Dec 28, 2025
Merged

fix: restore stdin redirect for Claude sandbox #41

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16 changes: 5 additions & 11 deletions src/policyengine_api/agent_sandbox.py
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Original file line number Diff line number Diff line change
Expand Up @@ -97,12 +97,14 @@ def run_claude_code_in_sandbox(
# Escape the question and config for shell
escaped_question = question.replace("'", "'\"'\"'")
escaped_mcp_config = mcp_config_json.replace("'", "'\"'\"'")
# Run claude directly (no shell wrapper) - Modal handles stdin/stdout properly
# CRITICAL: < /dev/null closes stdin (otherwise Claude hangs waiting for input)
# 2>&1 merges stderr into stdout for unified streaming
cmd = (
f"claude -p '{escaped_question}' "
f"--mcp-config '{escaped_mcp_config}' "
"--output-format stream-json --verbose --max-turns 10 "
"--allowedTools 'mcp__policyengine__*,Bash,Read,Grep,Glob,Write,Edit'"
"--allowedTools 'mcp__policyengine__*,Bash,Read,Grep,Glob,Write,Edit' "
"< /dev/null 2>&1"
)
logfire.info(
"run_claude_code_in_sandbox: executing",
Expand All @@ -111,15 +113,7 @@ def run_claude_code_in_sandbox(
escaped_question_len=len(escaped_question),
)
# text=True, bufsize=1 enables line-buffered streaming
# stderr=modal.Sandbox.STDOUT merges stderr into stdout
process = sb.exec(
"sh",
"-c",
cmd,
text=True,
bufsize=1,
stderr=modal.Sandbox.STDOUT,
)
process = sb.exec("sh", "-c", cmd, text=True, bufsize=1)
print("[SANDBOX] claude CLI process started", flush=True)
logfire.info("run_claude_code_in_sandbox: claude CLI process started, returning")

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