Askell MCP server

askell-mcp

MCP server for the Askell payment and subscription API.

Connect it to Cursor, Claude Desktop, or any MCP client to discover Askell endpoints, inspect customers/contracts/billing, and call the API. Reads and writes are separate tools so clients can show their own approval UI on mutations.

Requirements

• An Askell account and secret API key (from the Askell dashboard)
• One of:
• Bun ≥ 1.4.0 (for bunx), or
• a prebuilt binary from Releases (no Bun needed)

Quick start

1. Get API keys

In the Askell dashboard, copy your private (secret) API key. Optionally also the public key (only needed for temporary payment-method / checkout status endpoints).

2. Add to your MCP client

Prefer two server entries if you have both production and sandbox keys. Tool names are the same on both; the client distinguishes them by the server key (askell-prod vs askell-sandbox). Each instance's instructions include the environment it is talking to.

Put keys in gitignored dotenv files, not in JSON. Copy .env.example:

• .env — production (ASKELL_ENV=production and that dashboard's keys)
• .env.sandbox — sandbox (ASKELL_ENV=sandbox and that dashboard's keys)

Bun does not auto-load .env.sandbox. --no-env-file stops the sandbox process from also reading a production .env that happens to sit in the cwd.

Cursor

Project file: .cursor/mcp.json. mcp.json.example is this shape. ${workspaceFolder} is the directory that contains that mcp.json (the repo root when the file is .cursor/mcp.json). In ~/.cursor/mcp.json, use an absolute envFile path.

With Bun:

{
  "mcpServers": {
    "askell-prod": {
      "command": "bunx",
      "args": ["--no-env-file", "x", "askell-mcp"],
      "envFile": "${workspaceFolder}/.env"
    },
    "askell-sandbox": {
      "command": "bunx",
      "args": ["--no-env-file", "x", "askell-mcp"],
      "envFile": "${workspaceFolder}/.env.sandbox"
    }
  }
}

With a binary (download askell-mcp-- from Releases, then chmod +x). Same envFile; the binary reads the environment Cursor injects:

{
  "mcpServers": {
    "askell-prod": {
      "command": "/absolute/path/to/askell-mcp-linux-x64",
      "envFile": "${workspaceFolder}/.env"
    }
  }
}

Reload the window after saving.

Claude Desktop

Config file:

• Linux: ~/.config/Claude/claudedesktopconfig.json
• macOS: ~/Library/Application Support/Claude/claudedesktopconfig.json
• Windows: %APPDATA%\Claude\claudedesktopconfig.json

No envFile field. The desktop process cwd is not your repo, so a relative .env path does not resolve. With Bun, pass an absolute --env-file:

{
  "mcpServers": {
    "askell-prod": {
      "command": "bunx",
      "args": ["--no-env-file", "--env-file=/absolute/path/.env", "x", "askell-mcp"]
    },
    "askell-sandbox": {
      "command": "bunx",
      "args": ["--no-env-file", "--env-file=/absolute/path/.env.sandbox", "x", "askell-mcp"]
    }
  }
}

A binary has no --env-file. Put the keys in env (plaintext in that JSON file):

{
  "mcpServers": {
    "askell-prod": {
      "command": "/absolute/path/to/askell-mcp-linux-x64",
      "env": {
        "ASKELL_ENV": "production",
        "ASKELL_PRIVATE_API_KEY": "your_production_secret_api_key",
        "ASKELL_PUBLIC_API_KEY": "your_production_public_api_key_optional"
      }
    }
  }
}

Quit Claude Desktop completely and reopen it. Saving the file is not enough.

Claude Code

Shortened. The full README is on GitHub.