Five Persona Engine
@kiro0x
LLM persona consistency engine — enforce JSON personality and style constraints across interactions. Prevents persona drift with 160,000 deductively-derived behavioral rules.
Overview
What is Five Persona Engine?
Five Persona Engine is an MCP server that integrates with the FIVE Persona Engine API to generate structured JSON persona constraints for LLMs. Instead of describing personality in words, it defines behavioral parameters the LLM executes as a recipe, eliminating persona drift. It is intended for developers building consistent AI character interactions.
How to use Five Persona Engine?
Install via pip (pip install five-mcp), set the FIVE_API_KEY environment variable (get a key at fiveengine.dev), then run the server (five-mcp) with any MCP-compatible client. Use the generate tool to produce persona constraints by providing a character name and four personality axis choices (Q1–Q4), with optional style sliders (S1–S4, default 3) and free-form text.
Key features of Five Persona Engine
- Generates structured JSON persona constraints via the FIVE engine
- Eliminates LLM persona drift with deterministic behavioral parameters
- Single
generatetool with required and optional parameters - API key authentication via environment variable
- Stdio transport for MCP client compatibility
- Each
generatecall costs $1 (one credit)
Use cases of Five Persona Engine
- Building consistent AI game characters that behave predictably
- Creating reliable role-playing assistants with stable personalities
- Developing customer service bots with predefined behavioral profiles
- Experimenting with persona-driven narrative generation
FAQ from Five Persona Engine
What does the generate tool do?
It takes a character name, four axis choices (Q1–Q4), optional style sliders, and optional free text, then returns a JSON constraint object that defines the persona's behavioral parameters.
How do I get started?
Install the package with pip install five-mcp, obtain an API key from fiveengine.dev, set it as the FIVE_API_KEY environment variable, then run the server with five-mcp or configure it in Claude Desktop's claude_desktop_config.json.
How much does it cost?
Each generate call costs $1 and consumes one credit. Credits can be managed at fiveengine.dev.
Does it require an internet connection?
Yes, the server calls the FIVE Persona Engine API, so an internet connection and a valid API key are required.
What transport does the server use?
It uses stdio transport, making it compatible with any MCP client.
