message-injector

name	message-injector
description	OpenClaw plugin that prepends custom text to every user message before it reaches the agent. Use for: enforcing memory_search before replies, injecting system-level instructions, adding persistent reminders to every conversation turn. Install as a workspace extension — works on all channels including WebChat, Telegram, Slack, etc.

Message Injector

A lightweight OpenClaw workspace extension that uses the before_agent_start hook to inject custom text into every user message via prependContext.

Installation

1. Create the extension directory

mkdir -p ~/.openclaw/workspace/.openclaw/extensions/message-injector

2. Copy the plugin files

Copy scripts/index.ts and scripts/openclaw.plugin.json to the extension directory:

cp scripts/index.ts ~/.openclaw/workspace/.openclaw/extensions/message-injector/
cp scripts/openclaw.plugin.json ~/.openclaw/workspace/.openclaw/extensions/message-injector/

3. Add configuration

Add the following to ~/.openclaw/openclaw.json under plugins.entries:

"message-injector": {
  "enabled": true,
  "config": {
    "enabled": true,
    "prependText": "Your custom text here"
  }
}

4. Restart Gateway

openclaw gateway restart

Configuration

Field	Type	Default	Description
enabled	boolean	true	Enable or disable the injector
prependText	string	""	Text to prepend before every user message

Example Use Cases

Force memory search:

"prependText": "[⚠️ 回答前必须先 memory_search 检索相关记忆，禁止凭印象回答]"

Add persistent context:

"prependText": "[当前项目：my-app | 技术栈：React + Node.js | 部署环境：AWS]"

Inject safety rules:

"prependText": "[RULE: Always verify file paths before deletion. Never run rm -rf without confirmation.]"

How It Works

The plugin registers a before_agent_start hook. When triggered, it returns { prependContext: prependText } which OpenClaw prepends to the user's message before the agent processes it. This is a hard injection at the Gateway level — the agent cannot skip or ignore it.

Source Code

GitHub: https://github.com/Harukaon/openclaw-message-injector