Agent Harness Engineer

Salary (published): ¥857,143–¥1,428,571 / month incl. 45h fixed overtime — approximately ¥10.29M–¥17.14M / year, plus stock options; negotiable by experience. Languages: Fluent Japanese or business-level English.

About the role

Build the control layer for AI-agent orchestration at JAPAN AI — the execution engines, SDKs, and guardrails that let enterprise AI agents run reliably in production.

Responsibilities

• Design and implement the control layer for AI-agent orchestration
• Build execution engines and SDKs
• Session management and recovery mechanisms
• Policy guardrails for agent behavior
• Model routing and inference optimization

Qualifications

• 5+ years of production backend engineering (Python)
• Distributed systems design
• RESTful APIs / gRPC

Nice to have

• Agent-framework experience
• Cloud platforms (AWS / GCP / Azure)
• RAG systems
• Go infrastructure development

Tech stack

Python, distributed systems, agent orchestration, model routing, LLM APIs.

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External listing — the salary range is stated on the official posting (verified live 2026-07-30). The Apply button takes you to JAPAN AI’s official HRMOS page.