README.md

metadata

pretty_name: StreamStop
language:
  - en
license: cc-by-4.0
viewer: false
size_categories:
  - 1M<n<10M
tags:
  - language-model-agents
  - adaptive-stopping
  - reasoning
  - offline-evaluation
  - arxiv:2610.27981

StreamStop: Agent Reasoning Trajectories with Prefix-Level Action Annotations

JunHyeok Oh and Byung-Jun Lee, Korea University
Paper · Project page

Dataset accompanying Adaptive Stopping of Streamed Reasoning for Language Model Agents.

A completed reasoning trajectory records its final action, but does not reveal the actions the model would generate from earlier reasoning prefixes. StreamStop supplies these prefix-action annotations while holding each decision's environment context fixed. Researchers can train stopping policies and compare their action agreement and reasoning-token use offline, without additional reasoning-model calls or environment rollouts after collection.

Collection

Configuration	Episodes	Nonempty reasoning streams	Prefix-action annotations
WebShop / Qwen3.8-27B	5,237	40,922	443,611
WebShop / Nemotron-30B	3,437	20,021	374,499
ScienceWorld / Qwen3.8-27B	1,260	30,885	791,006
ScienceWorld / Gemini 3.1 Flash-Lite	1,260	31,991	487,700
Total	11,194	123,819	2,096,816

The full collection includes successful and unsuccessful episodes and invalid action responses. It contains 123,820 decision records, including one Gemini decision with empty reasoning. Annotation coverage varies across streams. The paper's training and validation experiments use a filtered subset from successful collection episodes; the full collection should not be confused with that subset. Closed-loop test evaluation rollouts are not included.

Gemini uses an explicit plan with native thinking disabled. Its prefix lengths use the prefix reader's tokenizer units; they do not represent native reasoning traces or API billing savings.

Files and records

Each of webshop_q38, webshop_nemo, sciworld_q38, and gemini_sciworld contains:

• episodes.jsonl.gz: episode summaries, task identifiers, success and outcomes.
• decisions.jsonl.xz: public context, full reasoning, reference action and parser results.
• prefix_actions.jsonl.xz: prefix length k, generated responses/actions and reference parser results.

This release provides the original compressed JSONL files. The automatic viewer is disabled because episodes, decisions, and prefix annotations have different record schemas; use the download and reading example below.

All are UTF-8 JSON Lines. JSON records retain their original fields; optional fields differ across configurations. manifest.json records collection counts and checksums.

Join decisions and annotations using configuration, source_shard, split, goal, step, and attempt (default zero when absent). Episodes use configuration, source_shard, split, and goal. k and sample_index distinguish prefix annotations. Keep repeated collection samples separate, and preserve the recorded task-level split when building experiments.

Download and read

from huggingface_hub import snapshot_download
from pathlib import Path
import gzip, json, lzma

root = Path(snapshot_download("jh2525/StreamStop", repo_type="dataset"))

def iter_records(path):
    opener = lzma.open if path.suffix == ".xz" else gzip.open
    with opener(path, "rt", encoding="utf-8") as stream:
        for line in stream:
            if line.strip():
                yield json.loads(line)

prefixes = iter_records(root / "webshop_q38/prefix_actions.jsonl.xz")
record = next(prefixes)
print(record["k"], record["parse"])

Compressed files can be read sequentially without decompressing the complete collection to disk. examples/read_records.py supplies a local reading example.

Interpretation

Action agreement compares a prefix action with the recorded full-reasoning reference action. It is not a ground-truth correctness label: another action can also succeed in the environment. Offline agreement evaluation is distinct from closed-loop task-success evaluation. See the paper for collection prompts, parsing, filtering, and stopping protocols.

License and source terms

CC BY 4.0 applies to our original prefix-action annotations. Benchmark content and model outputs retain their applicable upstream terms. This license does not relicense those assets. See SOURCE_TERMS.md and LICENSE.

No model weights are included. Provider request identifiers, credentials, and internal filesystem paths are not part of this release.

Citation

Please cite the accompanying paper:

@article{oh2026streamstop,
  title={Adaptive Stopping of Streamed Reasoning for Language Model Agents},
  author={Oh, JunHyeok and Lee, Byung-Jun},
  journal={arXiv preprint arXiv:2610.27981},
  year={2026},
  eprint={2610.27981},
  archivePrefix={arXiv},
  primaryClass={cs.CL},
  url={https://arxiv.org/abs/2610.27981}
}