arksim 0.3.5

⛵️ Know how your agent performs before it goes live.

⛵️ ArkSim

Simulate multi-turn conversations with your AI agent. Find failures before production.

Documentation · Examples · Report a Bug

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What is ArkSim?

Agents fail in ways that only show up mid-conversation. They misinterpret intent three turns in, call the wrong tool, or hallucinate a policy that does not exist. Single-turn testing misses all of this.

ArkSim generates LLM-powered synthetic users that hold realistic multi-turn conversations with your agent. Each user has a distinct profile, goal, and knowledge level. They push back, ask follow-ups, and behave like real users would.

You define scenarios, ArkSim simulates conversations, then evaluates every turn across metrics like helpfulness, faithfulness, and goal completion. The output is an interactive report showing exactly where your agent broke and why.

Quickstart

Have an agent? Test it in 3 commands:

pip install arksim
export OPENAI_API_KEY="your-key"
arksim init
# Edit my_agent.py with your agent logic, then run:
arksim simulate-evaluate config.yaml

This generates config.yaml, scenarios.json, and a starter my_agent.py.

For HTTP or A2A agents: arksim init --agent-type chat_completions or arksim init --agent-type a2a. For Anthropic or Google as the evaluation LLM: pip install "arksim[anthropic]" or pip install "arksim[google]".

Just exploring? Try an example:

pip install arksim
export OPENAI_API_KEY="your-key"
arksim examples
cd examples/e-commerce
arksim simulate-evaluate config.yaml

What you'll see

The report tells you where your agent is strong and where it breaks. You get per-metric scores, categorized failures, and full conversation transcripts so you can read the exact turns where things went wrong.

Test Your Own Agent

Python class (default)

arksim init generates a my_agent.py with a BaseAgent subclass. Replace the execute() body with your agent logic:

from arksim.simulation_engine.agent.base import BaseAgent
from arksim.simulation_engine.tool_types import AgentResponse

class MyAgent(BaseAgent):
    async def get_chat_id(self) -> str:
        return "unique-id"

    async def execute(self, user_query: str, **kwargs: object) -> str | AgentResponse:
        # Replace with your agent logic
        return "agent response"

Chat Completions endpoint

agent_config:
  agent_type: chat_completions
  agent_name: my-agent
  api_config:
    endpoint: http://localhost:8000/v1/chat/completions

A2A protocol

agent_config:
  agent_type: a2a
  agent_name: my-agent
  api_config:
    endpoint: http://localhost:9999/agent

A2A agents can also surface tool calls for evaluation via the arksim tool call capture extension. See examples/customer-service/a2a_server/ for a runnable reference server.

Write scenarios that match your agent's domain. See the Scenarios documentation for how to define goals, user profiles, and knowledge.

Why ArkSim?

• Simulation, not just evaluation. Most tools score conversations you already have. ArkSim generates them with synthetic users who push back, ask follow-ups, and behave unpredictably.
• Multi-turn by default. Every test is a full conversation, not a single prompt. Context loss, tool misuse, and contradictions only show up across turns.
• Any agent, any framework. Works with 14+ frameworks through Chat Completions, A2A, or direct Python import.
• Runs in CI. Add it as a quality gate on every PR. Exits non-zero when your agent drops below threshold.
• Fully open source. Runs on your infrastructure. Your data never leaves.

Integrations

Framework	Provider
Claude Agent SDK	Anthropic
OpenAI Agents SDK	OpenAI
Google ADK	Google
LangChain	LangChain
LangGraph	LangChain
CrewAI	CrewAI
Dify	Dify
AutoGen	Microsoft
LlamaIndex	LlamaIndex
Pydantic AI	Pydantic
Rasa	Rasa
Smolagents	Hugging Face
Mastra	TypeScript
Vercel AI SDK	TypeScript

See examples for end-to-end projects with custom metrics and scenarios.

Learn More

Topic
Evaluation metrics (built-in and custom)	Metrics guide
CI integration (pytest and GitHub Actions)	CI setup guide
Configuration reference (all YAML settings)	Schema reference
Simulation and CLI usage	Simulation guide
Web UI for browsing results	Overview

Development

git clone https://github.com/arklexai/arksim.git
cd arksim
pip install -e ".[dev]"
pytest tests/

Linting and formatting:

ruff check .
ruff format .

See CONTRIBUTING.md for guidelines.

License

Apache-2.0. See LICENSE.

Citation

@misc{shea2026sage,
      title={SAGE: A Top-Down Bottom-Up Knowledge-Grounded User Simulator for Multi-turn AGent Evaluation},
      author={Ryan Shea and Yunan Lu and Liang Qiu and Zhou Yu},
      year={2026},
      eprint={2510.11997},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2510.11997},
}

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