Kiln AI

Kiln AI is an open source Python framework for building synthetic worlds for AI agent evaluations and reinforcement learning.

Seahaven is an open source Python framework designed to build synthetic worlds for AI agents. It addresses the challenge of evaluating multi-turn agents by providing isolated, stateful, and resettable environments with known starting fixtures. The framework runs on SQLite and Python functions, allowing agents to read, write, and test actions without affecting shared resources. Seahaven integrates with OpenEnv, Model Context Protocol clients, and web consoles for manual inspection. It is built for developers who need reproducible, parallel testbeds to grade agent performance based on state changes rather than just transcripts.

Kiln AI at a glance

Best for: Software engineer, Researcher
Runs on: Python, API, Web, self-hosted, open source
Pricing: Free individual plan; Team and Enterprise plans available for Kiln Pro features and support.
Released: October 2026
Category: AI research tool
Website: kiln.tech/blog/introducing_seahaven

Key features

Private world per run
Reusable starting fixtures
Hundreds of parallel instances
State diff grading
Reproducible execution
Composable world building
OpenEnv and MCP integration
Web console UI

Use it for

Building synthetic worlds for AI agent evals
Running reinforcement learning environments
Testing multi-turn agent interactions with stateful tools
Grading agent changes using state diffs

Alternatives to Kiln AI

Seahaven — Provides isolated, reproducible, and stateful synthetic environments for agents.
Kungfu — Maintains work state and context when switching between different AI agents.
Beeuni — Agents retain context and improve skills over time through a controlled review process.
Webwright — Enables code-based web automation with reusable and rerunnable scripts.
Karotte — It runs tasks in isolated virtual machines for safety and consistency.
Burr — It offers observability and state management for complex AI agents.
BeeAI Framework — Provides constraint enforcement for predictable agent behavior.
NemoClaw — Provides managed security, networking, and lifecycle operations for AI agents.
Reef — Connects agent inference, feedback, model training, and deployment.
MyAgent — It features built-in permission controls, long-term memory, and skill self-evolution.
PySpur — A development environment for debugging and deploying reliable AI agents.
Cheshire Cat — Build and extend custom artificial intelligence agents using pure Python code.

All Kiln AI alternatives