---
id: ba189013-3890-4464-a22d-cdc3d68d8068
type: solution
title: "Fixed PostToolUse hook context injection"
tags: [claude-code, hooks, pai, fix, memorygraph]
importance: 0.8
confidence: 0.8
created: "2025-12-07T07:26:28.700934+00:00"
updated: "2025-12-07T07:32:04.922535+00:00"
---

PostToolUse hooks cannot inject stdout directly into Claude context - only SessionStart and UserPromptSubmit can. The fix is to use JSON output with additionalContext field: {hookSpecificOutput: {hookEventName: 'PostToolUse', additionalContext: 'your message'}}. Also discovered tool_response (not tool_output) is the correct field name, and exitCode doesn't exist - must infer success from stdout patterns. Full reference: https://notes.manticorum.com/reference/claude-code-hooks-context-injection