NextTokenAI/NextSearch-1-S
NextSearch-1-S
NextSearch-1-S is the mid-size NextSearch-1 web research agent: a post-trained model that decomposes a question, searches and fetches from the live web, reconciles conflicting evidence, and returns a concise answer or a structured research artifact. The family is built to work as the research component inside a larger system — called repeatedly by an orchestrator — where per-call accuracy, tail latency, and cost compound. S is the family's serving sweet spot: MoE inference economics with near-M accuracy on breadth benchmarks.
Technical report: [nexttoken.co/research/nextsearch-1](https://nexttoken.co/research/nextsearch-1). Harness, evaluation suite, and audited benchmark golds: [github.com/NextTokenAI/nextsearch](https://github.com/NextTokenAI/nextsearch).
Results
Live-web evaluation (August 2026), against open models of its class. Benchmarks: SEAL-0 (fresh/conflicting evidence, n=97), FRAMES (multi-constraint retrieval, n=100), DeepSearchQA (comprehensive answer sets, n=100), WideSearch-sub (structured table sub-tasks, n=49), and WideSearch (full tasks under the orchestrated harness, n=20). Best per column in bold.
The table above is the conservative arm (parallel search backend). With the recommended exa-auto backend, S's four-bench mean rises ~+10pp to 0.738 (all four benches up) at ~1.3× episode cost; see the serving notes.
† published deep-research baselines, self-hosted under our harness; their rows ran under a more generous turn budget than the rest of the table (upper bounds). \ self-hosted: $/ep excludes GPU time. All rows run under our harness (same tools, prompts, turn budgets, pinned task date) against audited golds* with one shared judge — consistent within this table, not comparable to other papers' leaderboards. Protocol and reproduction: docs/evals.md; full analysis in the technical report.
Quick start
vllm serve NextTokenAI/NextSearch-1-S \
--enable-auto-tool-choice --tool-call-parser hermes --max-model-len 65536Recommended sampling: temperature 0.7, max 16k tokens per turn, thinking on. The model expects a task date in its system prompt and two tools (search, fetch); the exact prompts and tool schemas it was tuned for ship in the harness:
pip install nextsearch && nextsearch-eval run --benches seal0 --models nextsearch-1-s --n 10Or plain transformers:
from transformers import AutoModelForCausalLM, AutoTokenizer
model = AutoModelForCausalLM.from_pretrained(
"NextTokenAI/NextSearch-1-S", torch_dtype="auto", device_map="auto")
tokenizer = AutoTokenizer.from_pretrained("NextTokenAI/NextSearch-1-S")Serving pitfalls that fail silently (tool-call parsing, context caps, thinking retention): docs/serving.md.
License
Released under the Apache License 2.0, as is the base model `Qwen/Qwen3.6-35B-A3B`.
Citation
@techreport{nextsearch1,
title = {NextSearch-1: Open models for wide and deep web research},
author = {Nitish Kulkarni and Alankar Jain},
institution = {NextToken},
year = {2026},
url = {https://nexttoken.co/research/nextsearch-1}
}