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.

Model Base Params
NextSearch-1-M Inkling-Small 276B-A12B MoE weights
NextSearch-1-S (this repo) Qwen3.6-35B-A3B 35B-A3B MoE weights
NextSearch-1-XS Qwen3.5-9B 9B dense weights

Technical report: nexttoken.co/research/nextsearch-1. Harness, evaluation suite, and audited benchmark golds: 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.

SEAL-0 FRAMES DeepSearchQA WideSearch-sub WideSearch mean $/ep mean turns
NextSearch-1-S (avg@2) 0.381 0.830 0.620 0.737 0.730 $0.072 7.0
inkling-med (API) 0.433 0.810 0.689 0.683 0.709 $0.052 8.2
qwen3.6-35b-a3b (base) 0.402 0.790 0.638 0.732 0.619 $0.025 9.2
nemotron-3-super (120B-A12B) 0.320 0.740 0.538 0.462 $0.028 10.9
gemma-4-31b 0.155 0.670 0.565 0.667 $0.013 5.0
gpt-oss-120b 0.227 0.670 0.450 0.406 $0.018 9.3
tongyi-dr-30b (30B-A3B) † 0.351 0.780 0.407 0.322 0.388 $0.011* 20.4
quest-35b-rl (35B-A3B) † 0.371 0.740 0.467 0.157 0.382 $0.023* 24.0

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 65536

Recommended 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 10

Or 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}
}
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