Winnr

What Winnr MCP server does

The Winnr MCP server exposes Winnr’s cold-email infrastructure API through MCP. It covers domain discovery and provisioning, DNS configuration, SMTP mailbox management, inbox inspection, message retrieval, and sending email from a mailbox. Account and usage tools show plan limits and current capacity, while export tools produce mailbox credentials in supported CSV formats.

The available domain operations include searching for one or many domains, listing and inspecting owned domains, checking DNS providers, viewing required records, verifying DNS, tagging domains, connecting externally owned domains, and deleting domains. Mailbox operations include listing, creating, updating, and deleting email users. The server also includes inbox tools for listing messages and retrieving message bodies.

How it works

Winnr MCP server can run as a hosted remote endpoint at https://mcp.winnr.app/mcp or locally through uvx winnr-mcp over stdio. The hosted mode uses Winnr sign-in with OAuth 2.1 and PKCE. Local mode uses an API token beginning with wnr_.

Permission scopes separate observation from changes. The read scope permits inspection, write adds creation, updates, sending, and deletion, and purchase permits operations that spend money. A token’s scope determines which tools are exposed to the client. The server also marks tools with MCP annotations describing read-only, destructive, and idempotent behavior.

Many provisioning and mailbox actions are asynchronous. After starting an operation, an agent can inspect the job, list recent jobs, or wait for completion while receiving progress notifications. Purchase operations use a quote-and-confirm flow: the first call returns current pricing and a time-limited confirmation token, and the charge occurs only after confirmation.

Setup and configuration

For hosted use, add the remote endpoint as a custom MCP connector and complete Winnr sign-in. For local use, install uv and configure the client to run uvx winnr-mcp with WINNR_API_TOKEN in its environment. The server validates the token against the account endpoint during startup.

Optional settings include WINNR_API_URL for an alternate API host, WINNR_TIMEOUT for request timeouts, WINNR_READ_ONLY to register only read tools, and WINNR_NO_PURCHASES to hide tools that charge the card. Command-line options can override these environment settings.

Tools and capabilities

Winnr MCP server provides tools for:

• Account details, usage limits, asynchronous jobs, and CSV export formats.
• Domain search, bulk availability checks, purchasing, setup, connection, DNS verification, tagging, and deletion.
• Mailbox creation, bulk creation, updates, credential export, inspection, and deletion.
• Inbox listing, message-body retrieval, and sending with threading headers.
• DNS status for MX, SPF, DKIM, and DMARC, plus records for manual configuration.

It also provides read-only resources for account, usage, domains, DNS, warming, and jobs, along with parameterized playbooks for setup, health checks, reply triage, connecting an owned domain, and scaling infrastructure.

Limitations and notes

Local execution is intended for desktop MCP clients; hosted execution also supports web and mobile clients identified by the README. The export link for mailbox credentials lasts 15 minutes, and retrieved message bodies are truncated at 10,000 characters. Bulk domain-provider checks support up to 20 domains per call, bulk domain searches support up to 100 names, and bulk mailbox creation supports up to 100 mailboxes on one domain.

Buying domains and enabling paid features can charge the account card, so purchase calls require a separate confirmation step. Deleting a domain removes its mailboxes, and deleting a mailbox is destructive. A read-only token automatically hides tools that create, send, buy, or delete resources.