Use Breakpoint Engine with Claude

Breakpoint Engine is an MCP server, and Claude speaks MCP natively: connect the hosted cloud endpoint in claude.ai (web and desktop) as a custom connector, or run the open-source engine locally with Claude Code and Claude Desktop.

Before you connect (cloud)

1. Create an account and buy a credit pack.
2. Use the same Auth0 identity when Claude prompts for OAuth.

claude.ai — custom connector (cloud)

• Requires a Claude plan with connectors (Pro, Max, Team, or Enterprise).

1. Open Settings → Connectors → Add custom connector.
2. Name: Breakpoint Engine. URL: https://cloud.breakpointengine.com/mcp.
3. Leave the OAuth client ID and secret fields empty — Claude registers itself via dynamic client registration.
4. Click Connect and complete the Auth0 sign-in.
5. Enable the connector in a chat, then ask Claude to call opm_schema to confirm the tools are available.

Claude Code (CLI)

Cloud (metered, no local build needed):

claude mcp add --transport http --scope user breakpointengine-cloud https://cloud.breakpointengine.com/mcp

1. Run /mcp inside Claude Code.
2. Select breakpointengine-cloud and complete the browser OAuth flow.
3. Ask for opm_schema, then opm_estimate before solves.

Local (unmetered, private — cap tables never leave your machine). Clone and build the open-source engine, then:

docker compose build opm-mcp
claude mcp add --scope user breakpointengine -- docker run -i --rm breakpointengine/opm-mcp:local

Claude Desktop

Cloud: use Settings → Connectors exactly as on claude.ai when remote MCP is available.

Local: add the stdio server to claude_desktop_config.json (Settings → Developer → Edit config):

{
  "mcpServers": {
    "breakpointengine": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "breakpointengine/opm-mcp:local"]
    }
  }
}

Working pattern

1. Prepare your cap table in the documented JSON format.
2. opm_estimate first; use it to set max_work (cloud is metered).
3. opm_forwardsolve / opm_backsolve for full runs, or opm_scenario_begin → step / query / mutate → commit for interactive round design.

Troubleshooting

• Connection failed immediately — confirm the URL is exactly https://cloud.breakpointengine.com/mcp and that you can sign in at /account.
• Registration / OAuth error — leave client ID/secret blank; dynamic registration must be enabled on the Auth0 tenant (operator setting).
• Connects but tools return 401 — reconnect so the token is a JWT for the cloud API audience.
• 402 / insufficient_credits — buy a pack on account.

Also see ChatGPT setup, Cursor setup, and the tool reference.