Hook errors after running "/compact" command inside Claude Code

[cheuk-cheng]

After I have installed claude-praetorian-mcp plugin successfully in Claude Code, if I run "/compact" command I will always see the following errors.

❯ /compact                                                                                                                            
  ⎿  Compacted (ctrl+o to see full summary)
     PreCompact [${CLAUDE_PLUGIN_ROOT}/hooks/entrypoints/pre-compact.sh] completed successfully: {
       "continue": true,
       "suppressOutput": true
     }
     PreCompact [node ${CLAUDE_PLUGIN_ROOT}/hooks/pre-compact.js] failed: Hook JSON output validation failed:
       - : Invalid input

     The hook's output was: {
       "hookSpecificOutput": {
         "additionalContext": "⚜️  [claude-praetorian] Context compaction imminent - SAVE NOW.\n\nCall praetorian_compact() to preserve
      valuable work before context resets:\n- type: "decisions" for architectural choices and trade-offs\n- type: "file_reads" for
     codebase patterns and key file locations\n- type: "task_result" for subagent findings and exploration results\n- type:
     "web_research" for API docs and external research\n\nAuto-merges with existing compactions of the same title."
       }
     }

     Expected schema:
     {
       "continue": "boolean (optional)",
       "suppressOutput": "boolean (optional)",
       "stopReason": "string (optional)",
       "decision": ""approve" | "block" (optional)",
       "reason": "string (optional)",
       "systemMessage": "string (optional)",
       "permissionDecision": ""allow" | "deny" | "ask" (optional)",
       "hookSpecificOutput": {
         "for PreToolUse": {
           "hookEventName": ""PreToolUse"",
           "permissionDecision": ""allow" | "deny" | "ask" (optional)",
           "permissionDecisionReason": "string (optional)",
           "updatedInput": "object (optional) - Modified tool input to use"
         },
         "for UserPromptSubmit": {
           "hookEventName": ""UserPromptSubmit"",
           "additionalContext": "string (required)"
         },
         "for PostToolUse": {
           "hookEventName": ""PostToolUse"",
           "additionalContext": "string (optional)"
         }
       }
     }
  ⎿  Read AGENTS.md (169 lines)
  ⎿  SessionStart:compact hook error