Xianliang Liu

LLM Post-Training & Agent Engineering

I work on LLM post-training and agent systems, with a focus on multi-turn reinforcement learning, reward design, and tool use. Currently at Meituan; previously interned at Alibaba, 360, and AMD.

Open to remote part-time and contract work, primarily in LLM post-training.

Selected work

Meituan

Ongoing

Multi-turn agent RL · Livestream Q&A

Responsible for post-training a digital human livestream commerce Q&A agent powered by an in-house MoE model. Built multi-turn agent RL environments with verl, using GRPO and related methods including GiGPO to train ReAct-based reasoning and tool use.

  • Designed reward components for output format, response length, trajectory turn count, and retrieval of relevant RAG information.
  • Implemented separate product and store retrieval tools, combining keyword/BM25 retrieval with vector search to supply relevant information for answers.
  • Connected multi-turn information gathering to livestream Q&A, with average end-to-end response time under 2 seconds.

Alibaba

2025.06 – 2025.09

Qwen assistant · Post-training & planner rewards

Contributed to Qwen assistant development and Qwen3 post-training for task planning and tool use. Used verl and GRPO for reinforcement learning, with responsibility for reward design for the Planner module.

  • Contributed to multi-agent workflows spanning intent clarification, complex task decomposition, planning, and tool use across services.
  • Worked on synthetic query generation, data filtering and distillation, and multi-source RL rewards using LLM-as-judge.
  • Supported YaRN-based context extension and decoupled training/inference deployment, including routing scripts adapted to Alibaba’s infrastructure.
  • Enabled 4B and 32B models to replace Qwen-Max in several modules.

360

2025.03 – 2025.05

Visual reasoning · Post-training & evaluation

Built 400,000 image-text training examples spanning math, code, and open-ended QA. Applied SFT, DPO, and GRPO, designed reference-based RL rewards, and developed automated business-task evaluations with OpenCompass.

AMD

2023.01 – 2023.06

Algorithm intern · Assisted driving

Developed vehicle pose estimation and parking-space detection and tracking for assisted parking, with deployment and testing on a modified BYD Han EV.

Education

Xidian University

Master’s program, Computer Technology

2023 – 2026

Bachelor’s program, Artificial Intelligence

2019 – 2023