Assay
MCP Setup

Add Assay to Your Editor

Verify code inside Claude Code, Cursor, or Windsurf. 3 minutes to set up.

What is an MCP server?

MCP (Model Context Protocol) gives AI coding assistants new abilities — like installing a plugin. Adding the Assay MCP server gives your assistant 4 tools:

verify-code

Paste code and get a verification report

verify-file

Point at any file to verify it

generate-code

Generate verified code from a description

health-check

Confirm the Assay connection works

Before you start

  • Node.js 20+ — node --version
  • Claude Code, Cursor, or Windsurf installed
1

Create your Assay account

Sign up free. No credit card required.

Create Free Account
2

Copy your API key

Go to API Keys, click Generate New Key, copy the lk_live_ key.

Save your key — you cannot see it again. You will paste it in the next step.

3

Add MCP config to your editor

Choose your editor, then follow the instructions.

  1. Open Claude Code in your terminal
  2. Type /mcp to see your MCP settings
  3. Or edit the config file directly (path below)
  4. Paste the configuration and save
  5. Restart Claude Code

Config: ~/.claude/claude_desktop_config.json

json
{
  "mcpServers": {
    "assay": {
      "command": "npx",
      "args": ["-y", "assay-mcp"],
      "env": {
        "ASSAY_API_KEY": "lk_live_your_key_here"
      }
    }
  }
}

Replace lk_live_your_key_here with your real key from Step 2.

4

Try it out

After restarting your editor, try these prompts:

>“Can you verify this file for bugs?”
>“Use Assay to check src/auth/login.ts”
>“Generate a verified rate limiter in TypeScript”
>“Run a health check on the Assay connection”

All set. Assay runs inside your editor using the same pipeline that caught bugs in projects with 50K+ GitHub stars.

Troubleshooting

Tools do not appear

Restart your editor. In Claude Code, type /mcp to check. In Cursor, check Settings > MCP.

ASSAY_API_KEY required error

Check that you replaced lk_live_your_key_here with your real key. No extra spaces.

401 Unauthorized

Key may be invalid or expired. Generate a new one from the dashboard.

Slow first start

First launch downloads from npm (10-20s). Subsequent launches are instant.

Prefer the command line? CLI Setup Guide