Connect Lasso with MCP

This guide walks you through creating a Lasso Pro API token in CRM and launching the AWS Labs OpenAPI MCP Server against it. Any agentic environment that speaks MCP can then call the same Lasso Pro API described on the API page.

You need a Lasso login with Project Admin on the project you want to expose, plus an MCP host that can run a local uvx command (Cursor, Claude Code, Claude Desktop, Windsurf, and similar).

1. Create a Lasso Pro API token

  1. Sign in at app.lassocrm.com. After login you land on the Lasso home screen.
Lasso home screen after login, with Sales Center, Inventory, Client Admin, and Project Admin cards
Lasso home after you sign in. Integrations live under the Project Admin card.
  1. On the Project Admin card, open the gear menu and choose Integrations Configuration.
  2. Stay on the Project Tokens tab.
Integrations Configuration Setup with the Project Tokens tab and a table of existing tokens
Project Tokens lists every integration key on your account. Use Generate New API Token to add one for MCP.
  1. Click Generate New API Token.
  2. Choose the project the assistant should work in.
  3. Set Vendor to Lasso Pro API.
  4. Click Generate. The first Lasso Pro API token on a project adds that project to your Lasso Pro API bill (shown on the form before you confirm).
  5. Copy the raw token (or use Show Key on that row later). Store it as LASSO_PRO_API_KEY. Paste the JWT as-is — no Bearer prefix.
Generate Token for Project form with a project selected and Vendor set to Lasso Pro API
Select the project, choose Lasso Pro API, then Generate. You can later use Show Key on the same row if you need to copy the token again.

2. Install uv

The AWS Labs server is launched with uvx, which ships with uv. On macOS or Linux:

curl -LsSf https://astral.sh/uv/install.sh | sh

Restart the terminal (and the MCP host) so uvx is on your PATH. Confirm with uvx --version.

3. Add the server to your MCP host

Every host gets the same stdio recipe. The file you edit and the way you reference LASSO_PRO_API_KEY are the only client-specific bits — that is how AWS Labs and the MCP clients themselves document this.

Commanduvx
Argsawslabs.openapi-mcp-server@latest (pin a version such as @1.1.6 if you do not want it to move on every launch)
API_NAMElasso-pro
API_BASE_URLhttps://api.lassocrm.com/v1
API_SPEC_URLhttps://platform.lassocrm.com/api/lasso.yml
AUTH_TYPEbearer
AUTH_TOKENyour Lasso Pro API token (or the host’s env interpolation for LASSO_PRO_API_KEY)

Put this block in whatever file your host uses for MCP servers (often named mcp.json, .mcp.json, or claude_desktop_config.json). Windsurf, Kiro, and most others accept this mcpServers shape. VS Code Copilot uses a servers key in .vscode/mcp.json instead — same command, args, and env.

{
  "mcpServers": {
    "lasso-pro": {
      "command": "uvx",
      "args": ["awslabs.openapi-mcp-server@latest"],
      "env": {
        "API_NAME": "lasso-pro",
        "API_BASE_URL": "https://api.lassocrm.com/v1",
        "API_SPEC_URL": "https://platform.lassocrm.com/api/lasso.yml",
        "AUTH_TYPE": "bearer",
        "AUTH_TOKEN": "<your Lasso Pro API token>"
      }
    }
  }
}

Prefer an environment variable over pasting the token.

User-wide: ~/.cursor/mcp.json. Project-only: .cursor/mcp.json. Or Settings → MCP.

{
  "mcpServers": {
    "lasso-pro": {
      "command": "uvx",
      "args": ["awslabs.openapi-mcp-server@latest"],
      "env": {
        "API_NAME": "lasso-pro",
        "API_BASE_URL": "https://api.lassocrm.com/v1",
        "API_SPEC_URL": "https://platform.lassocrm.com/api/lasso.yml",
        "AUTH_TYPE": "bearer",
        "AUTH_TOKEN": "${env:LASSO_PRO_API_KEY}"
      }
    }
  }
}

Project-shared: .mcp.json at the repo root. User-wide: claude mcp add --scope user (writes ~/.claude.json).

claude mcp add --transport stdio \
  --env API_NAME=lasso-pro \
  --env API_BASE_URL=https://api.lassocrm.com/v1 \
  --env API_SPEC_URL=https://platform.lassocrm.com/api/lasso.yml \
  --env AUTH_TYPE=bearer \
  --env 'AUTH_TOKEN=${LASSO_PRO_API_KEY}' \
  --scope user \
  lasso-pro -- uvx awslabs.openapi-mcp-server@latest

Single quotes keep the shell from expanding the token when you run the command. The same server as JSON:

{
  "mcpServers": {
    "lasso-pro": {
      "type": "stdio",
      "command": "uvx",
      "args": ["awslabs.openapi-mcp-server@latest"],
      "env": {
        "API_NAME": "lasso-pro",
        "API_BASE_URL": "https://api.lassocrm.com/v1",
        "API_SPEC_URL": "https://platform.lassocrm.com/api/lasso.yml",
        "AUTH_TYPE": "bearer",
        "AUTH_TOKEN": "${LASSO_PRO_API_KEY}"
      }
    }
  }
}

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json. Windows: %APPDATA%\Claude\claude_desktop_config.json. Put the token in AUTH_TOKEN in that file.

{
  "mcpServers": {
    "lasso-pro": {
      "command": "uvx",
      "args": ["awslabs.openapi-mcp-server@latest"],
      "env": {
        "API_NAME": "lasso-pro",
        "API_BASE_URL": "https://api.lassocrm.com/v1",
        "API_SPEC_URL": "https://platform.lassocrm.com/api/lasso.yml",
        "AUTH_TYPE": "bearer",
        "AUTH_TOKEN": "<your Lasso Pro API token>"
      }
    }
  }
}

4. Try it

This token can create, update, and delete project data, not only read it. Leave your host’s tool-approval prompts on.

  1. Restart the MCP host so it picks up the new server.
  2. Confirm lasso-pro is listed and connected.
  3. Ask the assistant for something scoped to that project, for example: “List the Lasso project this key can access, then show one registrant.”

The token is a project-scoped bearer credential for https://api.lassocrm.com/v1. The live OpenAPI description is https://platform.lassocrm.com/api/lasso.yml.

Support

If something in this flow does not match what you see in Lasso, Contact Us