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Varity MCP Server Reference

Varity TeamCore Contributors

The Varity MCP server (@varity-labs/mcp) runs locally over stdio and gives an MCP-compatible editor access to Varity’s published tools. The install command uses npm’s current latest release; an unreleased source branch is not evidence of what that command installs.

Prerequisites

Section titled “Prerequisites”
  • Node.js 22.11 or newer, as required by the package currently published to npm
  • Python 3.11 or newer for the current varitykit CLI
  • varitykit, installed with pipx install varitykit

Setup

Section titled “Setup”

Add this to .cursor/mcp.json in your project:

{
  "mcpServers": {
    "varity": {
      "command": "npx",
      "args": ["-y", "@varity-labs/mcp"]
    }
  }
}

Restart Cursor after saving the file.

Authentication

Section titled “Authentication”

Use varity_login for interactive setup. For a headless process, provide VARITY_API_KEY (or the package’s compatibility name VARITY_DEPLOY_KEY) to the MCP process. Never put a real key in a checked-in editor configuration.

The server can also read the credential written by varitykit. API keys are account credentials; a project path is not an ownership boundary.

Tool Reference

Section titled “Tool Reference”

Use /mcp-schema.json for conservative usage guidance and the release identity reviewed by Docs. Discover names, input schemas, and annotations from the installed server before calling a tool. Do not copy a tool table into automation from this page. The platform HTTP routes wrapped by deployment tools are separately published at /openapi.yaml.

Important lifecycle semantics:

  • A deploy, environment update, redeploy, or delete request can return before every runtime effect has converged. Track the returned state or operation.
  • Deletion acceptance is not proof that routing, allocation release, and billing closure are all complete.
  • A redeploy request reapplies saved configuration and can be a no-op. Do not describe it as a verified restart or image refresh without runtime evidence.
  • The deployment-log tool returns recent runtime logs of a live app. Use the local build tool for compilation diagnostics.
  • The environment tool accepts no values. It directs private configuration to a secret-safe interface, and no tool result echoes a secret.
  • The CPU machine tools list, create, and delete SSH-accessible machines. Create takes your SSH public key, and a machine bills hourly until it is deleted.

Typical Workflow

Section titled “Typical Workflow”
  1. Run varity_doctor to check local prerequisites.
  2. Run varity_login if authentication is missing.
  3. Use varity_cost_calculator or a live quote before a billable action.
  4. Build locally and inspect the result.
  5. Deploy the project or a certified template.
  6. Follow the returned deployment state to a terminal outcome.
  7. For deletion, verify terminal cleanup and billing state rather than treating request acceptance as closure.

The package also exposes local-development and repository helpers. Discover their current schemas and annotations from the installed server’s tools/list response before calling them. Use /mcp-schema.json only for conservative Docs guidance tied to its recorded release marker.

Transports

Section titled “Transports”

The package supports:

  • stdio, for local editor integrations; and
  • self-hosted HTTP, for a server you operate yourself.

Start a local HTTP transport with:

Terminal window
npx -y @varity-labs/mcp --transport http --port 3100

It serves MCP at http://localhost:3100/mcp.

Local-browser and local-dev-server tools require local execution, so use stdio for those workflows.

LLM Context Without MCP

Section titled “LLM Context Without MCP”

Clients that cannot run MCP can read:

  • https://docs.varity.so/llms.txt for the compact index; or
  • https://docs.varity.so/llms-full.txt for the generated documentation corpus.

These are documentation projections, not substitutes for live resource state, quotes, or operation receipts.

Troubleshooting

Section titled “Troubleshooting”
  • If npm cannot resolve the package, confirm node --version meets the published package requirement and retry npx -y @varity-labs/mcp.
  • If deploy tools cannot find varitykit, install it with pipx and run varitykit doctor.
  • If an editor does not show the server, validate its JSON configuration, restart the editor, and inspect the editor’s MCP process log.
  • If a tool’s behavior differs from this page, record the installed npm version first and use the matching package and platform contracts as evidence.

Support

Section titled “Support”