Founding Harness Engineer

Clera; United States; Remote; USD 120,000 - 180,000; Full time

Benefits offered by this job

Founding equity

Job summary

Clera Labs, Inc. is seeking an experienced AI engineer to join our early-stage team to build the agent runtime and evaluation systems that enable an AI coworker to act reliably in real team workflows. You will shape when agents take initiative, request approvals, or stay quiet.

You will design the runtime, refine system prompts, and develop evaluation harnesses, focusing on safety, scalability, and multi-tenant data handling while collaborating with the founding team and early users.

Qualifications

• Production experience shipping tool-using LLM agents.
• Hands-on system prompt design, tested iteratively.
• Experience building evaluation and regression test harnesses for LLM/agent behavior.
• Understanding safe tool execution, approvals workflows, and multi-user data risks.
• Strong ownership of broad technical problems and ability to explain tradeoffs.
• Experience with LLM agents, tool use, evaluations, and prompt engineering.

Responsibilities

• Design and build the agent runtime for providing context, selecting tools, requesting approvals, and completing work.
• Write and refine system prompts to make agent behavior proactive without becoming noisy or unsafe.
• Build evaluation and regression tests for real tasks, tool use, and failure cases.
• Improve reliability across long-running tasks, interruptions, and retries.
• Implement safeguards such as approval gates and multi-tenant data separation.
• Work directly with the founding team and early users to take broad problems from prototype to production.

Skills

LLM agents

Tool usage

Prompt engineering

System prompts

Test harnesses

Evaluation

Safety governance

Ownership

Tradeoffs

Tools

LLM tooling

Job description

About the Role

Join an early-stage AI team to build the agent runtime and evaluation systems that help an AI coworker act reliably in real team workflows. You will shape when agents take initiative, request approval, or stay quiet.

What You'll Do

• Design and build the agent runtime for providing context, selecting tools, requesting approvals, and completing work.

• Write and refine system prompts to make agent behavior proactive without becoming noisy or unsafe.

• Build evaluation and regression tests for real tasks, tool use, and failure cases.

• Improve reliability across long-running tasks, interruptions, and retries.

• Implement safeguards such as approval gates and multi-tenant data separation.

• Work directly with the founding team and early users to take broad problems from prototype to production.

What We're Looking For

• Production experience shipping tool-using LLM agents, beyond demos or thin prompt wrappers.

• Hands-on system prompt design, improved through testing and iteration.

• Experience building evaluation and regression test harnesses for LLM or agent behavior.

• Understanding of safe tool execution, approval workflows, and multi-user data risks.

• Strong ownership of broad technical problems and the ability to explain tradeoffs.

• Experience with LLM agents, tool use, evaluations, and prompt engineering.

Compensation & Benefits

Founding equity is offered; the percentage and vesting terms are to be confirmed.

Location

Remote, from Serbia, Poland, or another Eastern European country. Local employment or contractor structure and working-hour overlap are to be confirmed.