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AgentSynth

Synthetic, verified multi-step agent trajectories for fine-tuning agentic LLMs — tool-use, grounded code execution, and multi-agent collaboration — with a built-in LLM-as-Judge evaluation loop. It runs offline for free and scales up with any model.

The thesis in one line: the value isn't generating agent trajectories, it's generating ones you can trust. So verification is core, not a side feature.

Install

pip install agentsynth-ai                # core: generate + evaluate + export
pip install "agentsynth-ai[app]"         # + the Gradio UI
pip install "agentsynth-ai[all]"         # everything

60-second tour

from agentsynth import AgentTrajectoryGenerator, TrajectoryEvaluator, verify_trajectory

gen = AgentTrajectoryGenerator()                      # offline mock by default
traj = gen.generate("What's the weather in Paris, and 18% tip on $54?")

result = TrajectoryEvaluator().evaluate(traj)         # 6-dimension rubric
print(result.overall, result.passed)

print(verify_trajectory(traj).verified)               # re-checks tool args, execution, safety

Get on the leaderboard

core_v2 is the flagship pack — 14 tiered, outcome-checked business tasks over a writable SQL world, up to multi-table consistency. A run passes only when the world ends up in the goal state. The pack downloads itself, so this works anywhere:

agentsynth bench --pack core_v2 --model <your-model> --submit

The live board is at agentsynth.tech; --policy mypkg.module:fn benches your own agent loop instead of a LiteLLM model, and --trials k scores pass^k reliability. (core_v1 is a gentler 10-task starter.)

Where to go next

The live playground is at app.agentsynth.tech (mirrored on Hugging Face Spaces), and the code is on GitHub.