| MAILCHIMP_API_KEY | Yes | Mailchimp Marketing API key, including the '-dc' data-center suffix (e.g. 'abc...-us22'). Generate at Mailchimp → Account → Extras → API keys. |
| MAILCHIMP_BASE_URL | No | Override the API base URL (for mock servers or testing). Defaults to 'https://{dc}.api.mailchimp.com/3.0' derived from the API key suffix. |
| MAILCHIMP_TIMEOUT_MS | No | Per-request timeout in milliseconds. |
| MAILCHIMP_MAX_RETRIES | No | Max retry attempts for transient upstream failures (0-10). |
| MAILCHIMP_CONCURRENCY_LIMIT | No | Max in-flight upstream requests across this process (1-10). |
| MAILCHIMP_ASSETS_DIR | No | Absolute path to a local assets directory. When set (Node-only — Workers ignored), enables the `mailchimp_assets` tool and auto-uploads `@assets/<path>` references in campaign HTML to Mailchimp File Manager at send time. Cache at <dir>/.mailchimp-cache.json. |
| MAILCHIMP_TEMPLATES_DIR | No | Absolute path to a local templates directory. When set (Node-only), enables the `mailchimp_local_templates` tool and support for `content.localTemplate` on campaign tools. Templates are `.eta` files with optional YAML frontmatter; legacy `<name>.meta.yaml` sidecars are read when frontmatter is absent. Canonical write path on free-tier Mailchimp. |
| MCP_LOG_LEVEL | No | Minimum log level for output: debug, info, notice, warning, or error. |
| MCP_TRANSPORT_TYPE | No | Selects the HTTP transport. |
| MAILCHIMP_API_KEY | Yes | Mailchimp Marketing API key, including the '-dc' data-center suffix (e.g. 'abc...-us22'). Generate at Mailchimp → Account → Extras → API keys. |
| MAILCHIMP_BASE_URL | No | Override the API base URL (for mock servers or testing). Defaults to 'https://{dc}.api.mailchimp.com/3.0' derived from the API key suffix. |
| MAILCHIMP_TIMEOUT_MS | No | Per-request timeout in milliseconds. |
| MAILCHIMP_MAX_RETRIES | No | Max retry attempts for transient upstream failures (0-10). |
| MAILCHIMP_CONCURRENCY_LIMIT | No | Max in-flight upstream requests across this process (1-10). |
| MCP_HTTP_HOST | No | The hostname for the HTTP server. |
| MCP_HTTP_PORT | No | The port to run the HTTP server on. |
| MCP_HTTP_ENDPOINT_PATH | No | The endpoint path for the MCP server. |
| MCP_AUTH_MODE | No | Authentication mode to use: 'none', 'jwt', or 'oauth'. |
| MCP_LOG_LEVEL | No | Minimum log level for output: debug, info, notice, warning, or error. |