MCP Waifu Chat Server

Overview

The MCP Waifu Chat Server is a lightweight, protocol‑compliant backend that brings a customizable “waifu” conversational AI to any MCP‑enabled client. By exposing user management, dialog history, and a simple chat endpoint through the Model Context Protocol, it allows developers to plug an engaging character into their own AI assistants without writing custom integration code.

This server solves the common pain point of managing persistent user state and conversation context when building role‑playing or character‑based chatbots. It stores each user’s dialog history in a SQLite database, enabling the assistant to reference past exchanges and maintain continuity across sessions. The modular design means new tools or storage backends can be added with minimal effort, making it a flexible foundation for experimentation or production use.

Key capabilities include:

• User lifecycle tools – Create, verify existence, delete, and count users via MCP tools, giving clients fine‑grained control over participant management.
• Dialog history API – Retrieve, set, or reset a user’s conversation log, allowing assistants to fetch context for prompt construction or to clear stale data.
• Chat endpoint – A single request that forwards the user’s prompt to a chosen LLM (OpenRouter or Gemini), returns the model output, and automatically persists the exchange.
• Configurable defaults – Environment‑driven settings for database path, default genre, and fallback responses ensure the server can be tailored to any deployment scenario.
• Testing harness – Comprehensive unit tests validate database interactions and API behavior, providing confidence when integrating into larger systems.

Typical use cases involve building themed chat assistants: a romance or fantasy companion in a game, an educational tutor that remembers past lessons, or a brand mascot that maintains personality across interactions. By leveraging MCP’s tool‑based architecture, developers can expose these capabilities to Claude or other assistants and orchestrate complex workflows—such as combining the waifu chat tool with a scheduling tool or sentiment analyzer—to create rich, context‑aware experiences.

Unique advantages of this server are its simplicity and extensibility. The entire stack is written in Python 3.10+, relies on well‑maintained libraries (, , and the Google GenAI SDK), and uses SQLite for zero‑configuration persistence. This means teams can spin up a fully functional character server in minutes, focus on refining the persona, and scale out by swapping the database or LLM provider without touching the MCP contract.