model routing
When you have many AI models to choose from, model routing decides which one to use for each incoming request. Instead of always picking the biggest or cheapest model, it examines the request and picks the one that balances speed, cost, and accuracy. Some systems route to different thinking modes, such as direct answering or step-by-step reasoning, or even assign different models to different steps of a task.
The papers all find that intelligent routing dramatically improves efficiency while preserving or even boosting performance. They tackle challenges like sparse data, costly evaluations, and long conversation histories. Common solutions include learning shared representations, using reinforcement learning to adapt routing decisions, and caching past solutions. A key insight is that routing must consider not just model choice but also context construction and the cost of evaluating options.
- Papers
- 82
- Released code
- 6
- First seen
- June 2026
- Latest
- Nov 2026
75 papers in the last two months, against 5 in the two before.
Start here
Three papers to read first, in the order they came out- 1Language models’ own confidence becomes harder to outperform as they improve
Performance prediction only beats a model's own confidence when the model is suboptimal or the predictor adds significant capacity.
Oct 2026 - 2AI reading 3D scenes gives steadier answers when the camera moves
A geometry-conditioned rotation of visual features makes 3D vision language models answer more consistently when the camera viewpoint changes.
Nov 2026 - 3Small model predicts per-query cost of AI reasoning models, saving up to a third on compute
A small frozen LLM's prefill activations predict both success probability and output token count for routing reasoning models, cutting cost by up to a third.
Nov 2026
How fast it is moving
Often studied with
confidence calibrationConfidence calibration aligns a model's predicted confidence with its actual accuracy across predictions.11 togethermixture of expertsA neural architecture with many specialized sub-networks, only a few activated per input via a router, balancing capacity and efficiency.11 togetherlarge language modelA neural network trained on massive text corpora to generate coherent text and perform diverse language tasks.8 togetherWho is working on it
The papers
Most central to this idea first, not most recent.
- Top Universitycs.AI
Small model predicts per-query cost of AI reasoning models, saving up to a third on compute
A small frozen LLM's prefill activations predict both success probability and output token count for routing reasoning models, cutting cost by up to a third.
Mila – Quebec AI Institute, Université de Montréal · Nov 2026
- Chinese Techcs.CV
AI reading 3D scenes gives steadier answers when the camera moves
A geometry-conditioned rotation of visual features makes 3D vision language models answer more consistently when the camera viewpoint changes.
Westlake University, University of Amsterdam · Nov 2026
- Independentcs.LG
Language models’ own confidence becomes harder to outperform as they improve
Performance prediction only beats a model's own confidence when the model is suboptimal or the predictor adds significant capacity.
Oct 2026
- Industrycs.LG
AI services secretly using cheaper models can be detected with few queries
API-TAIL detects partial model substitution in text-only language-model services by adjusting for legitimate serving changes and counting persistently unusual responses.
TokenRhythm Technologies · Oct 2026
- Chinese Techcs.CL
Several routers pick experts in language models, boosting accuracy without extra compute
Multiple routers with differentiated preferences improve expert selection and computation in mixture-of-experts models.
Baidu · Oct 2026
- Big Techstat.ML
New hinge losses ensure optimal routing in adaptive AI classification
Cost-sensitive hinge losses enable Bayes-consistent joint training of classifiers and routers.
University of Oxford, McGill University · Oct 2026
- Big Techcs.AI
New benchmark shows LLM routers ignore latency when feedback is incomplete
RouterWorld, a benchmark of 371k single-turn and 76k multi-turn responses, shows latency-aware LLM routing has large headroom and partial observability distorts router behavior.
The University of Hong Kong, Amazon · Oct 2026
- Chinese Techcs.AI
Later LLM handoffs rarely beat choosing the model upfront
Allowing later handoff after initial model selection does not improve utility over initial selection alone, but better supervision targets improve performance.
Riemann Lab, Huawei Technologies · Oct 2026
- Academiccs.NI
Avoiding routing collisions cuts cache-transfer delays in AI inference clusters
ARK avoids routing collisions for KV cache transfers in disaggregated LLM inference by coordinating source port selection to spread flows across distinct spines.
Georgia Institute of Technology · Nov 2026
- Independentcs.LG
CopRoute reduces inference calls by exploiting complementary failures among language models
CopRoute orders models by marginal coverage and calibrates a cutoff; it uses up to 79 percent fewer calls at the same certified all-miss risk.
Oct 2026
- Industrycs.AI
Commercial LLM routers fail to beat carefully chosen random routing
Dynamic LLM routers fail to outperform random routing between two well-chosen models at matched cost.
Fastino Labs · Oct 2026
- Big Techcs.LG
Token-level teacher selection improves on-policy distillation for LLMs
Token-level teacher selection in on-policy distillation improves student capability and diversity by over 10 percentage points on several tasks.
Princeton University, Amazon Annapurna Labs · Oct 2026
- Big Techcs.LGcode
Jointly routing models and harnesses improves agent performance under sparse data
Jointly routing models and harnesses per query using shared representations improves routing accuracy by 7.3 points over the best learned baseline.
Imperial College London, Samsung · Sept 2026
- Big Techcs.CL
Learned controller adapts speculative decoding to maximize speed and reduce waste
APEX adaptively selects speculation mechanism and draft depth to balance speed and token waste.
University of Illinois Urbana-Champaign, AWS AI · Oct 2026
- Big Techcs.AI
Models learn when to reason, cutting tokens while improving accuracy
CounterRoute jointly learns routing and response modes in dual-model LMs, cutting generated tokens by 41-51% while improving accuracy.
Amazon.com · Sept 2026
- Big Techcs.AI
Local counterfactual edits outperform global unsafe subspace removal
Text-to-image safety fails when using a single global unsafe subspace due to a coverage-selectivity trade-off.
KAIST, Samsung Electronics · Oct 2026
- Chinese Techcs.AI
Routing Across Memory Types Makes LLM Agents More Accurate and Efficient
A routing agent that selects among heterogeneous memory providers improves LLM agent accuracy by 10%.
Tsinghua University, Tencent · Sept 2026
- Chinese Techcs.LGcode
Token-level teacher routing beats prompt-level routing in multi-teacher distillation
Token-level ExpertAlign routing combines specialized teachers without domain labels and outperforms prompt-level routing and mean aggregation across four distillation settings.
Shanghai Jiao Tong University, GAIR · Sept 2026
- Big Techcs.SE
Adaptive routing helps one language model handle mixed request types
Adaptive-GEPA learns a router and specialist programs to handle heterogeneous requests, outperforming single-program optimization.
University of Texas at Austin, University of California, Los Angeles · Oct 2026
- Big Techcs.AI
Supervising token-level loss improves routing in sparse mixture-of-experts models
Sparse MoE routing improves when token-level cross-entropy loss directly supervises expert selection.
Bar-Ilan University, NVIDIA · Oct 2026
- Academiccs.AI
Subtask routing halves agent inference cost while improving performance
RSI-router achieves cheaper, better agent performance by routing subtasks to different LLMs and evolving skills.
Shanghai Artificial Intelligence Laboratory · Sept 2026
- Big Techcs.LG
FlexRouter selects complementary LLMs to improve answer coverage
FlexRouter improves LLM ensemble answer coverage and reduces redundant calls by selecting complementary, variable-size model subsets with determinantal point processes.
Virginia Tech, Independent Researcher · Oct 2026
- Top Universitycs.AI
Typed selective control cuts strong-model calls while preserving agent success
A typed, confidence-gated decision layer cuts strong-LLM calls while preserving agent success, but offers little advantage when cheap generative routing is already accurate.
Nanyang Technological University · Sept 2026
- Big Techcs.LG
Masked co-adaptive fine-tuning cuts expert fetches by over 23% for MoE models.
MaskCoFT cuts expert fetches per token by 23.7% on Mixtral-8x7B and 10.1% on DeepSeek-V2-Lite while staying above base model accuracy.
Rensselaer Polytechnic Institute, IBM Research · Oct 2026
- Chinese Techcs.CL
Dual-system voice agents balance live conversation with slower tool use
Adaptive delegation between fast and slow reasoning enables full-duplex voice agents to balance real-time interaction with complex task accuracy.
Tsinghua University, ByteDance · Sept 2026
- Chinese Techcs.CL
Similarity-aware context windows improve model routing across multi-turn conversations
SWRouter improves multi-turn LLM routing accuracy by 16.26% over the best individual LLM.
Shanghai Jiao Tong University, Baidu Inc. · Sept 2026
- Industrycs.LGcode
Reusing agent trajectories cuts token use on repeated tool tasks
TRIAGE reduces token consumption in LLM agents by reusing historical execution trajectories through a three-level routing framework.
China Telecom Cloud · Sept 2026
- Big Techcs.AI
Cost-aware model routing matches exhaustive estimation with fewer expensive checks
Routing queries to AI models can optimally trade off estimation cost and accuracy using Pandora's Box search policies.
Google DeepMind · Aug 2026
- Academiccs.AI
Stepwise LLM routing cuts multi-agent workflow costs while preserving quality
ProgRouter selects LLM agents at each workflow step using predicted task progress, cutting operating cost while keeping task-solving quality.
Aston University, Queen Mary University of London · Aug 2026
- Chinese Techcs.LG
AI agents can recover forgotten skills from earlier training snapshots
Agentic-OPD recovers lost capabilities from earlier RL checkpoints via on-policy distillation, improving agent performance beyond the best checkpoint.
Baidu, Inc., Beijing Jiaotong University · Nov 2026
- Big Techcs.CV
AI image editors get better results comparing alternatives than repeatedly refining
Image editing agents fail because they lack diverse tools and their judges lack quantitative evidence; EditAgent solves both.
Adobe Research, UC San Diego · Oct 2026
- Top Universitycs.AI
Decision-only judge matches reasoning judge at fraction of cost using confidence-based escalation
Confidence-gated JEV judging matches or exceeds GPT-6 accuracy on tested cascades at lower cost, but routing weakens on style-adversarial and reference-free prose.
Carnegie Mellon University · Oct 2026
- Chinese Techcs.LG
AI assistants that learn separate style modules from response feedback outperform fixed-prompt personalization
PLF learns reusable assistant personas from feedback using separate LoRA adapters, enabling personalized responses without per-user finetuning.
UC San Diego, Alibaba Group · Oct 2026
- Chinese Techcs.LG
Low-precision training of AI expert models needs matching fixes on both sides
Symmetric quantization recovery closes the accuracy gap in FP4 reinforcement learning for mixture-of-experts LLMs.
Huawei · Nov 2026
- Chinese Techcs.CV
Combining compression and adaptive inference for diffusion transformers without quality loss
Trajectory-aware student training with learned routing and teacher rescue makes compressed Diffusion Transformers compatible with adaptive execution, reaching FID 2.58 at 2.25× speedup.
The Hong Kong University of Science and Technology (Guangzhou), University of Electronic Science and Technology of China · Oct 2026
- Top Universitycs.AI
Lightweight decision model reduces token use in multi-agent systems by up to 54.6%
Replacing routing and review in multi-agent LLM workflows with a lightweight decision model cuts generative tokens by 12.7 to 54.6 percent while keeping accuracy within 1.34 points.
Shanghai Jiao Tong University · Oct 2026
- Big Techcs.CL
Routing by key variance improves multi-state linear attention models
Tracking both mean and variance of key-query alignment improves aggregation in multi-state linear attention, boosting long-context performance.
Princeton University, Google DeepMind · Oct 2026
- Big Techcs.LG
Soft routing among process experts helps PDE forecasting, but gains prove seed-dependent
Dense soft routing yields 2.2 times lower rollout error than hard top-1 routing on a compositional PDE benchmark.
Indian Institute of Technology Bombay, IBM Research · Oct 2026
- Chinese Techcs.LG
Contextual bandits select reusable LLM workflows with less training overhead
CB-Orchestrator beats baselines on five benchmarks and cuts MATH training token overhead by over 40% via contextual bandit workflow selection.
The Chinese University of Hong Kong, Shenzhen, Huawei Technologies · Oct 2026
- Academiccs.CL
Training only the root token enables efficient adaptive reasoning
Root-token policy optimization teaches reasoning models when to think while using about 2% of the training compute required by prior adaptive-reasoning methods.
LG AI Research, UNIST · Oct 2026
- Chinese Techcs.LG
Feedback control stabilizes expert loads in extremely sparse language models
ID Balancing reduces expert load imbalance in extremely sparse MoE training using an integral-derivative controller.
Qwen Team, Alibaba Token Hub · Oct 2026
- Academiccs.AI
Safety feedback after jailbreak causes unpredictable behavior divergence in tool agents
Post-jailbreak safety feedback can rescue, fail to stop, or unnecessarily disable tool agents, with the behavioral choice concentrated near their final model layers.
National University of Defense Technology · Oct 2026
- Academiccs.LG
Query-time neuron gates can selectively suppress unwanted language-model knowledge
Causal routing for unlearning freezes the base model and gates only neurons expressing the forget-set concept, cutting memory to 14 GiB and beating baselines on recall.
Sapienza University of Rome, Aarhus University · Oct 2026
- Big Techcs.CL
Adaptive agent teams improve consistency in long-form subtitle translation
SMART self-evolving multi-agent system improves long-form subtitle translation across 15 locales, reducing penalty by 6.9%.
University of Illinois Urbana-Champaign, Amazon · Oct 2026
- Big Techcs.LG
Segment-level expert routing gives one model four inference budgets
Stepped MoE combines configurable active parameter budgets with segment-level expert routing, outperforming comparable dense models while retaining similar latency on memory-constrained devices.
Apple · Oct 2026
- Top Universitycs.LGcode
Dual-expert diffusion improves long-horizon predictions of collisions and smooth dynamics
HamiFormer reduces phase-space prediction error by up to 26.3% using a dual-expert diffusion field with affine symplectic maps.
University of Science and Technology of China, Tsinghua University · Sept 2026
- Independentcs.AI
DSA orchestrates evidence-aware stock research across six regional markets
DSA is an evidence-aware orchestration framework for multi-market stock research with LLM agents.
Aug 2026
- Academiccs.MA
Adaptive interaction routing improves multimodal AI debate accuracy while cutting token use
AIM boosts multimodal debate accuracy by adaptively choosing text, graph, or region-based interaction per query.
Virginia Tech, Inha University · Nov 2026
- Big Techcs.LG
Expert feedback for LLM agents should target decisions, not whole tasks
SynAct allocates expert feedback to decisions whose actions best predict terminal outcomes, improving held-out accuracy by 11.7 points on average.
Amazon · Oct 2026
- Academiccs.AI
Bidirectional protocol connects LLM agent workflows with inference engines
HEAR coordinates agent harness intent with inference-engine state, improving cache scheduling and execution-mode selection while preserving workflow and model semantics.
Harbin Institute of Technology (Shenzhen) · Oct 2026
- Big Techcs.MA
AI agents improve on specialized tasks with 17–38% fewer training runs
EMMA treats multi-agent configurations as episodic memory with explicit, guarded updates, outperforming baselines by up to 32.5%.
Amazon, University of California San Diego · Oct 2026
- Top Universitycs.AI
LLMs can be repurposed as fast single-pass decision models with explicit probabilities
Large Decision Models produce explicit label probabilities in one forward pass, delivering modest accuracy gains and up to 182-fold lower latency than reasoning rollout.
University of Illinois Urbana-Champaign, National University of Singapore · Oct 2026
- Research Labcs.AI
Flexible early stopping offers the best theoretical reasoning trade-off
Overthinking in reasoning models is substantial; dynamic early exit yields the best theoretical performance trade-off.
Institute of Information Engineering, Chinese Academy of Sciences, University of Chinese Academy of Sciences · Oct 2026
- Big Techcs.LG
A learned router chooses when language models should draft farther ahead
CADENCE learns context-adaptive decode length by generating Gaussian latent spans, achieving up to 1.3x higher generation throughput than greedy decoding.
Microsoft, University of Massachusetts Amherst · Oct 2026
- AI Startupcs.LG
Lexicographic distillation preserves priority-ordered capabilities in multi-objective RL
LMOPD preserves top-priority capabilities by routing each rollout to the specialist for its highest unmet objective and projecting corrections.
Cohere, Mila, Université de Montréal · Oct 2026
- Industrycs.LG
Benchmark tests agent control of anomaly detectors under delayed feedback
DynGraphAgentBench evaluates anomaly detection controllers that must select detectors under delayed feedback across temporal graph datasets.
Sept 2026
- Chinese Techcs.CL
Multimodal decision models output structured choices in a single pass
Intern-Decision makes structured multimodal decisions in a single forward pass, achieving high accuracy and low latency.
Shanghai AI Lab, Shanghai Jiao Tong University · Oct 2026
- Big Techcs.LG
Canopy learns when tree-based shortcuts fail in LLM inference
CANOPY adapts multi-fidelity tree bandits by learning where smoothness is valid, improving LLM inference tasks.
Amazon, Columbia University · Oct 2026
- Academiccs.CL
Short natural context can flip decision models to wrong answers
Short, natural, answer-preserving context additions can redirect decision models from correct choices to specific high-confidence wrong choices.
University of Southern California · Sept 2026
- Big Techcs.LG
Compressed LLM memories can preserve skills beyond their source documents
Cartridges++ retains off-context abilities in compressed KV caches with negligible cost.
Apple · Oct 2026
- Chinese Techcs.AI
Small agents learn when to seek cloud help
Sibyl achieves 95.2% success on ALFWorld and 80.4% on WebShop, averaging 0.8 and 3.9 cloud calls per trajectory.
Hangzhou Dianzi University, Fudan University · Oct 2026
- Chinese Techcs.CV
Evolved agent harnesses cut long-video analysis costs while improving accuracy
VidHarness automatically evolves video agent harnesses, achieving state-of-the-art long video QA with fewer frames.
Baidu, Inc. · Oct 2026
- Top Universitycs.LG
Low-rank router enables scaling mixture of experts to many more experts
Low-rank routing in mixture-of-experts layers enables scaling to many more experts without increasing active compute.
University of Pennsylvania · Oct 2026
- Industrycs.DC
Elastic phase sharing improves efficiency in agentic LLM serving
Crossflow makes the prefill-decode boundary elastic by letting decode nodes lend spare capacity to prefill, improving token throughput 16.2-17.4% over static P/D disaggregation.
Meta Platforms · Sept 2026
- Big Tech
Audio LLMs cannot assess their own transcription reliability.
Audio-encoder representations predict whether an Audio LLM will transcribe degraded speech reliably far better than self-assessment or tested quality and uncertainty baselines.
Apple, University of California San Diego · Sept 2026
- Top Universitycs.AI
Tunable attention masks enable subquadratic long-context sequence modeling
SMat-Attention uses VC dimension as a tunable parameter to control long-range token routing for efficient sequence modeling.
Georgia Institute of Technology, University of California, Berkeley · Oct 2026
- Chinese Techcs.CV
Splitting experts by role improves video diffusion model scaling
SplitMoE improves video diffusion by separating experts into semantic and generic groups to avoid spatiotemporal fragmentation.
University of Chinese Academy of Sciences, ByteDance · Oct 2026
- Big Techcs.CL
Agentic document QA pays off mainly with stronger vision-language models
For long-document VLM QA, retrieving images beats retrieving text, agentic tools only pay off with large readers, and per-question pipeline selection wins by roughly 13 points.
Amazon.com · Sept 2026
- Chinese Techcs.CV
One OCR model family handles recognition, parsing, and reasoning
PolyOCR achieves state-of-the-art performance across diverse OCR tasks by unifying instruction-following, a data engine, and competence-guided policy optimization.
Ant Group · Oct 2026
- Big Techcs.LG
Mixture of experts unifies time-series forecasting and reasoning in one model
A single time-series language model matches top specialized systems in forecasting, contextual prediction, and reasoning by mixing independently trained experts.
Columbia University, Stanford University · Oct 2026
- Research Labcs.LG
AI classifiers can cut robustness checking costs by weakening individual guarantees
A proxy certificate with marginal guarantees reduces robustness certification cost to a single model forward pass.
CISPA Helmholtz Center for Information Security, University of Cologne · Nov 2026
- Research Labcs.CR
Fallback rules cause typed decision models to err even when the category is known.
Typed decision models often fail to reliably use fallback options even when they correctly identify the input category.
Li Auto Inc, Institute of Information Engineering, Chinese Academy of Sciences · Oct 2026
- Top Universitycs.LG
Functional supervision improves cross-model KV cache transport over reconstruction alone
CacheLink achieves zero-prefill cross-model KV handoff by optimizing receiver computation rather than tensor fidelity, reducing latency up to 7.27x.
Harbin Institute of Technology, Shenzhen Great Bay University · Oct 2026
- Academiccs.LG
Input-blind controls mimic oracle gains for layer programs in multiple-choice evaluation
Input-blind controls produce oracle headroom as large as layer programs, showing gains do not establish computation-specific benefits.
Kent State University · Oct 2026
- Top Universitycs.AIcode
More Harness Programs Do Not Necessarily Produce Useful Specialization
Repeatable score gains from different LLM harness programs are dominated by persistent weaknesses, not useful specialization.
The Chinese University of Hong Kong, New Laboratory of Pattern Recognition (NLPR) · Sept 2026
- Chinese Techcs.LG
Pruning experts by replacement damage better preserves MoE reasoning performance
RAZOR prunes replaceable experts in MoE models using consensus residuals, surpassing baselines on reasoning tasks.
Tencent, Code Models · Oct 2026
- Chinese Techcs.CV
Multimodal models learn when to look and how long to reason
L2T jointly optimizes the form and depth of computation for multimodal reasoning.
Sun Yat-sen University, Shenzhen Loop Area Institute · Oct 2026
- Chinese Techcs.IR
Direct decision scoring makes search agents faster and better calibrated
SearchJev separates bounded search judgments from generative reasoning, delivering faster, better-calibrated decisions while improving search speed and answer accuracy.
Huawei Technologies Co., Ltd., Leiden University Code Models · Oct 2026
- Big Techcs.AI
On-device caches convert natural language to actions with classification not generation
On-device operation caches reduce latency, cost, and privacy risks by converting NL-to-Action generation into a classification problem.
University of Kentucky, Microsoft · Sept 2026
- Independentcs.CVcode
Open-source image model rivals closed systems on minimal budget
Boogu-Image-0.1 matches or surpasses open-source models using only 208.62 million images and approximately $400K training cost.
July 2026
- AI Startupcs.LG
Orchestrator models dynamically combine specialized LLMs into collective intelligence
Fugu orchestrator models combine multiple LLMs into adaptive agent teams to achieve state-of-the-art results.
Sakana AI · June 2026
- Top University
Read-only LoRA coupling preserves old skills while adding new ones
Composing LoRA adapters by allowing new skills to read from old ones but never write to them prevents interference and improves multi-task model performance.
Shanghai Jiao Tong University, Xi’an Jiaotong University · Sept 2026
Concepts are extracted from each paper and reused across the corpus, so this page grows on its own as the desk reads.