Run Claude-compatible hooks (PreToolUse Bash, PreCompact, …) #24

Problem. AgentMux writes .claude/settings.json with a PreToolUse Bash hook (agentmux-bashwrap, live Bash streaming) and PreCompact. Mux Code runs no hooks.

Do. Claude's hook format: command hooks with JSON on stdin (session_id, transcript_path, cwd, permission_mode, hook_event_name, tool_name, tool_input, tool_use_id); exit code 2 blocks; JSON output decision/reason, hookSpecificOutput.permissionDecision (allow|deny|ask|defer), updatedInput, additionalContext. Events first: PreToolUse, PostToolUse, PreCompact; then UserPromptSubmit, Stop, SessionStart.

Spec §6.1.

Spec: SPEC_MUXCODE_HARNESS_AND_FEATURE_GAPS_2026_09_26.md