B4 Index MCP

Connect B4 to your AI

Point any MCP client at the B4 Index and your agent queries the current call instead of a stale export. Connecting takes no account. A key raises what the server will answer.

The server

Streamable HTTP. Same URL for every client and every plan.

https://b4-index.vercel.app/mcp
No credential needed to connect.

1 · Add the server

Pick your client and paste the block. This is the no-key setup.

Claude Code 
claude mcp add --transport http b4-index https://b4-index.vercel.app/mcp

Run in your terminal.

Claude Desktop 
{
  "mcpServers": {
    "b4-index": {
      "type": "http",
      "url": "https://b4-index.vercel.app/mcp"
    }
  }
}

Settings → Developer → Edit Config, then restart Claude Desktop.

Cursor 
{
  "mcpServers": {
    "b4-index": {
      "url": "https://b4-index.vercel.app/mcp"
    }
  }
}

Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global).

2 · Add your key

The server needs a plan. A B4 Web key unlocks b4_browse and b4_score, rate-limited and at capped vendor depth. A B4 Agent key unlocks the workflow tools and full vendor depth. Without a key every tool returns an upgrade pointer instead of a result. Mint a key in your cockpit, then send it as a bearer token:

Claude Code, with a key 
claude mcp add --transport http b4-index https://b4-index.vercel.app/mcp \
  --header "Authorization: Bearer b4_YOUR_KEY"

For the JSON clients, add "headers": { "Authorization": "Bearer b4_YOUR_KEY" } alongside the URL.

Open cockpit → API keys

The key is shown once. Copy it somewhere safe.

Or connect with one click (OAuth)

In Claude.ai or Claude Desktop, add https://b4-index.vercel.app/mcp as a custom connector and press Connect. Sign in with the same account as your B4 subscription and access follows your plan, with no key to paste.

The five tools

Browse and score require B4 Web or above. The three workflow tools require B4 Agent or Enterprise, using a key or an OAuth-signed session.

Connecting without a credential lets your client discover the tools, but calls return an upgrade pointer. The public directory remains available on the website without a plan.

  • b4_browse B4 Web Search and filter the 1,600+ categories by keyword, domain, quadrant, or industry.
  • b4_score B4 Web The five-dimension scorecard and verdict for a category, at capped vendor depth.
  • b4_audit B4 Agent Audit a whole stack — quadrant distribution plus BEWARE and overspend flags.
  • b4_compare B4 Agent Compare categories head-to-head on scores and trajectory.
  • b4_recommend B4 Agent Build/Buy/Bridge/Beware recommendation for a need or a stack.