WRIT: Write-Read Intensive Trajectory Synthesis for Multi-Turn User-Facing Agents

Hengrui Gu, Xiaotian Han, Kaixiong Zhou


Abstract
Multi-turn user-facing agents must infer user intent from incomplete requests, collect missing information through dialogue and tools, and execute valid actions. A training trajectory records this process as an interleaved sequence of user messages, agent responses, tool calls, etc. Synthesizing sufficiently complex trajectory has become a central route to train agents: existing pipelines often increase difficulty by composing multiple user requests into longer tasks, producing write-intensive trajectories that train sequential execution.

We argue that a single write decision can itself be difficult when the agent must gather and compare substantial read-tool evidence before its arguments become identifiable, a challenge that write-intensive data alone cannot address. Guided by this insight, we propose WRIT (Write-Read Intensive Trajectory Synthesis), a pipeline for synthesizing multi-turn agent training trajectories along two complexity axes: the number of write decisions in a task and the evidence burden of each individual decision. WRIT first generates write-intensive and read-heavy tasks. It then diversifies user behavior instructions to reflect realistic conversational variation, and finally simulates agent-user interactions in an executable environment to produce complete training trajectories. The resulting data trains agents not only for longer task execution, but also for robust, evidence-grounded decision making under high information load. With only 2K synthesized trajectories, a 4B model trained on WRIT outperforms GPT-5.1 no-think on 𝜏2-bench and substantially reduces inference-time token usage, showing that compact SFT data can convert part of expensive test-time reasoning into efficient agent behavior.
Anthology ID:
2026.emnlp-main.525
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
12115–12134
Language:
URL:
https://aclanthology.org/2026.emnlp-main.525/
DOI:
Bibkey:
Cite (ACL):
Hengrui Gu, Xiaotian Han, and Kaixiong Zhou. 2026. WRIT: Write-Read Intensive Trajectory Synthesis for Multi-Turn User-Facing Agents. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 12115–12134, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
WRIT: Write-Read Intensive Trajectory Synthesis for Multi-Turn User-Facing Agents (Gu et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.525.pdf