Undergraduate researcher · Fudan University

Junjie Nian 年骏杰

Understanding how AI systems reason.
Building agents that can recover and improve.

I study reasoning models, AI agents, and interpretability at FudanNLP Alex Lab, advised by Prof. Yixin Cao. My work connects the analysis of reasoning processes with methods for guiding agent behavior.

I am an undergraduate at Fudan University and an exchange student at UC San Diego for Fall 2026.

Research focus

From reasoning traces
to reliable decisions.

Reasoning processes

How do models reach the same answer through different computational paths?

SliceGraph

Agent behavior

Where do agents get stuck, and what helps them recover?

TraceGraph

Internal signals

Can model routing signals guide exploration and the choice of a final solution?

RISA

01 / Updates

News

  1. Released Trajectory Lens, a local tool built on TraceGraph for inspecting raw agent logs and comparing runs.

  2. ARM was selected as an Oral paper at EMNLP 2026.

  3. New paper: Disagree to Explore, Agree to Commit, introducing routing-guided test-time scaling for software agents.

  4. Released From Fluency to Accountability, an open claim-lifecycle analysis of ICLR 2026 peer review.

  5. New paper: MoE Routing as Signal for Reasoning Control.

Earlier updates 6 entries
  1. Released TraceGraph and SliceGraph.

  2. Thinking Traps in Long Chain-of-Thought (TAAR) was accepted to ACL 2026 Findings.

  3. Released CoT Folding, a structural analysis of LLM reasoning trajectories.

  4. Released NEX, a label-free method for Chain-of-Thought selection and model ranking.

  5. Released the TAAR preprint on measurable long-Chain-of-Thought traps and adaptive restart.

  6. Released ARM, a training-free approach to generalist LLM agent merging.

02 / Selected work

All research & projects

Three projects on understanding reasoning processes and using them to improve agent decisions.

RISA: routing signals guide action selection and final-patch arbitration Method overview

RISA Preprint · 2026 · Co-first author

Disagree to Explore, Agree to Commit

Routing-Guided Test-Time Scaling for Software Agents

Uses a model’s expert-routing signals to guide a software agent’s next action and select a final code patch, without an external judge or model-weight updates.

44.9% → 48.2% macro-average resolved rate on SWE-bench Verified across six gpt-oss conditions, comparing uniform selection with routing arbitration.

For the complete publication record, including an EMNLP 2026 Oral paper and work in ACL 2026 Findings:

View all publications

03 / Beyond research

Field notes

UC San Diego · Fall 2026 · Written in Chinese

我的 UCSD 交换经历

A personal record of the exchange process, from application and visa preparation to housing, courses, and life at UC San Diego.