Machine Learning Engineer (AI Agent Development)

Salary (published): ¥8,500,000–¥15,000,000 / year (base ¥567,000–¥1,001,000 / month incl. 35h fixed overtime). Languages: English proficiency required — Japanese is not required.

About the role

Design and build new services with LLMs and generative AI at LINE Yahoo: AI-agent development, Model Context Protocol (MCP) tooling, fine-tuning, and evaluation.

Responsibilities

• Design, develop, and implement new services using LLMs and generative AI
• AI-agent development
• Tool development via Model Context Protocol (MCP)
• Model fine-tuning
• Prompt engineering and evaluation
• Build LLM-integrated efficiency systems

Qualifications

• 3+ years of web/server development on Linux
• Foundational LLM knowledge plus hands-on experience
• Product improvement with NLP, computer vision, or ML
• Algorithms and data structures; AI/LLM security awareness

Nice to have

• Generative-AI service development
• LLM mechanisms (Tool Calling, Deep Research)
• Data design and collection
• ML/LLM security
• Peer-reviewed publications

Tech stack

LLMs, AI agents, Model Context Protocol, prompt engineering, Python, NLP.

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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 the official LY Corporation careers page.