Vibe Check MCP is a metacognitive oversight layer for AI agents that implements the Model Context Protocol (MCP). It works as a "meta-mentor" for your AI agents, providing reflective pauses and interrupts that help prevent reasoning errors and improve agent performance. According to research, agents using Vibe Check showed nearly doubled success rates and halved harmful actions.
# Clone and install
git clone https://github.com/PV-Bhat/vibe-check-mcp-server.git
cd vibe-check-mcp-server
npm install
npm run build
Create a .env file with your API keys:
# Gemini (default)
GEMINI_API_KEY=your_gemini_api_key
# Optional providers
OPENAI_API_KEY=your_openai_api_key
OPENROUTER_API_KEY=your_openrouter_api_key
# Optional overrides
DEFAULT_LLM_PROVIDER=gemini
DEFAULT_MODEL=gemini-2.5-pro
Start the server:
npm start
For a more streamlined setup, use the helper script:
bash scripts/docker-setup.sh
This script:
If you prefer manual Docker setup:
docker build -t vibe-check-mcp .
docker run -e GEMINI_API_KEY=your_gemini_api_key -p 3000:3000 vibe-check-mcp
Add to claude_desktop_config.json:
"vibe-check": {
"command": "node",
"args": ["/path/to/vibe-check-mcp/build/index.js"],
"env": { "GEMINI_API_KEY": "YOUR_GEMINI_API_KEY" }
}
Use the vibe_check function to get metacognitive oversight for your agent:
import { vibe_check } from 'vibe-check-mcp';
const result = await vibe_check({
goal: 'Write unit tests',
plan: 'Use vitest for coverage',
sessionId: 'demo1'
});
console.log(result.questions);
You can set per-session rules that the Chain-Pattern Interrupt (CPI) system will honor:
// Set rules for a session
await update_constitution({
sessionId: 'demo1',
rules: ['no external network calls', 'prefer unit tests before refactors']
});
// Check effective rules
const rules = await check_constitution({ sessionId: 'demo1' });
// Clear session rules
await reset_constitution({ sessionId: 'demo1' });
Include instructions in your agent's system prompt:
As an autonomous agent you will:
1. Call vibe_check after planning and before major actions.
2. Provide the full user request and your current plan.
3. Optionally, record resolved issues with vibe_learn.
The primary tool that challenges assumptions and prevents tunnel vision. Call this after planning and before major actions.
Optional tool to capture mistakes, preferences, and successes for future reflection.
Set or merge session rules that the CPI layer will enforce.
Clear rules for a session.
Inspect effective rules for a session.
The optimal usage is to have your agent call vibe_check:
According to research, the optimal "interrupt dosage" is around 10-20% of steps in an agent's workflow.
Vibe Check implements Chain-Pattern Interrupt (CPI), a research-backed oversight method that injects brief "pause points" at risk inflection moments. This helps re-align agents to the user's priorities and prevents reasoning lock-in (RLI).
The research shows that CPI nearly doubles success rates (from ~27% to 54%) and roughly halves harmful actions (from ~83% to 42%).
For more information on the research, visit the CPI research paper.
To add this MCP server to Claude Code, run this command in your terminal:
claude mcp add-json "vibe-check" '{"command":"node","args":["/path/to/vibe-check-mcp/build/index.js"],"env":{"GEMINI_API_KEY":"YOUR_GEMINI_API_KEY"}}'See the official Claude Code MCP documentation for more details.
There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.
If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.
To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".
When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:
{
"mcpServers": {
"vibe-check": {
"command": "node",
"args": [
"/path/to/vibe-check-mcp/build/index.js"
],
"env": {
"GEMINI_API_KEY": "YOUR_GEMINI_API_KEY"
}
}
}
}To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.
Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.
The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.
You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.
To add this MCP server to Claude Desktop:
1. Find your configuration file:
~/Library/Application Support/Claude/claude_desktop_config.json%APPDATA%\Claude\claude_desktop_config.json~/.config/Claude/claude_desktop_config.json2. Add this to your configuration file:
{
"mcpServers": {
"vibe-check": {
"command": "node",
"args": [
"/path/to/vibe-check-mcp/build/index.js"
],
"env": {
"GEMINI_API_KEY": "YOUR_GEMINI_API_KEY"
}
}
}
}3. Restart Claude Desktop for the changes to take effect