Russian developer TheSashaDev has released girl-agent, an open-source AI character engine that simulates realistic human behavior through modular systems rather than prompt engineering. Created on May 4, 2026, the project has garnered 213 stars for its approach to building what the developer describes as "not a chatbot—a character with state" that operates as an authentic Telegram account via MTProto protocol.
Behavioral Architecture Replaces Conversational Patterns
Girl-agent distinguishes itself by implementing discrete behavioral modules instead of relying on language model prompting. The system explicitly does not respond to every message, positioning itself as a personality simulation rather than a traditional chatbot. Core behavioral systems include:
- Presence patterns with dynamic online/offline schedules varying by character profile
- Sleep cycle with night-time unavailability and low wake probabilities
- Daily scheduling for activities like classes, work, and commute that affect accessibility
- Relationship tracking through five dynamic counters: interest, trust, attraction, annoyance, and awkwardness
- Conflict system that escalates from spam or pressure into extended silence periods
- Long-term memory logging important events to markdown files for persistent recall
Technical Implementation via MTProto Protocol
The project is built with TypeScript (65.6%) and Rust (30.3%), operating as an authentic Telegram account through MTProto rather than as a bot. This enables genuine message reactions, typing indicators, and message edits that feel natural within the Telegram ecosystem. An "anti-AI" layer strips common ChatGPT conventions including markdown formatting, repetitive phrases, and rows of emojis.
Differentiation from Existing AI Companions
Unlike GPTs, Character.AI, or HeatherBot, girl-agent separates behavior into discrete, composable modules rather than relying solely on prompting techniques. This architectural approach allows for more predictable and controllable character behaviors while maintaining the complexity of human-like interaction patterns.
The project is source-available with restrictions on commercial deployment and public clones, balancing openness with control over how the technology is used.
Key Takeaways
- Girl-agent implements behavioral modules including sleep cycles, daily schedules, and relationship tracking rather than relying on prompt engineering
- Operates as an authentic Telegram account via MTProto, enabling natural message reactions, typing indicators, and edits
- Tracks five relationship dimensions: interest, trust, attraction, annoyance, and awkwardness
- Built with TypeScript (65.6%) and Rust (30.3%) with an "anti-AI" layer that strips ChatGPT conventions
- Released on May 4, 2026, accumulating 213 stars under a source-available license with commercial restrictions