---
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: "2026-03-01T06:21:07.729483+00:00"
relations:
  - target: 250d2fe0-5866-42f1-b83d-187b3a64fb84
    type: BUILDS_ON
    direction: incoming
    strength: 0.73
    edge_id: e8e3d8cf-6ccf-4b39-a625-466151c1b392
---

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