Advanced Reasoning Model For Complex Problem Solving

via “sustained multi-step reasoning”

Anthropic's 2026 flagship — strongest Claude for agents, long-horizon coding, and tool orchestration.

Unique: Combines advanced reasoning capabilities with a user-friendly interface, making complex logical tasks accessible.

vs others: More reliable than simpler models that lack depth in reasoning capabilities.

via “reasoning and multi-step problem decomposition”

TII's 180B model trained on curated RefinedWeb data.

Unique: Achieves strong reasoning performance through scale (180B parameters) and data quality (3.5T meticulously-cleaned RefinedWeb tokens) rather than specialized reasoning fine-tuning, enabling emergent reasoning capabilities across diverse domains without task-specific training.

vs others: Larger parameter count than reasoning-specialized models like Llama 2 70B enables better few-shot reasoning, but lacks explicit chain-of-thought fine-tuning that models like GPT-4 or Claude employ, potentially requiring more sophisticated prompting to achieve comparable reasoning quality.

via “reasoning and complex task decomposition”

Mistral's 12B model with 128K context window.

Unique: Trained explicitly for reasoning tasks with extended 128K context enabling multi-step reasoning chains and complex problem decomposition, though specific reasoning techniques not disclosed

vs others: Larger context window (128K vs 32K in Mistral 7B) enables longer reasoning chains without truncation, improving reasoning quality for complex multi-step problems

via “arc-agi benchmark reasoning and abstract problem-solving”

OpenAI's most powerful reasoning model for complex problems.

Unique: Achieves 87.5% on ARC-AGI through extended reasoning about visual-logical patterns and rule inference, exploring multiple hypotheses about transformation rules before committing to predictions — this reasoning-first approach outperforms pattern-matching baselines

vs others: Significantly outperforms GPT-4 and Claude on ARC-AGI (87.5% vs ~50-60%) by allocating extended reasoning to hypothesis formation and rule inference rather than direct pattern matching, demonstrating genuine abstract reasoning capability

via “adaptive-thinking-complexity-aware-reasoning”

Anthropic's most intelligent model, best-in-class for coding and agentic tasks.

Unique: Implements learned complexity routing that estimates problem difficulty from input tokens alone, without requiring explicit user hints or metadata. This is distinct from static reasoning budgets (o1, o1-mini) by dynamically allocating compute per-request based on inferred task characteristics, reducing wasted reasoning on trivial queries.

vs others: More efficient than fixed-reasoning-budget competitors by automatically scaling reasoning effort to task complexity, and more transparent than black-box reasoning models by still exposing thinking tokens when needed for debugging.

OpenAI's reasoning model with chain-of-thought problem solving.

Unique: This model uniquely combines chain-of-thought reasoning with a large context window for enhanced problem-solving capabilities.

vs others: It offers superior performance in reasoning tasks compared to traditional models by leveraging extended thinking time and context.

via “reasoning-model-support-with-extended-thinking”

Chat via OpenAI-Compatible API

Unique: Transparently supports reasoning models (o1, o3-mini, DeepSeek R1) with extended thinking capabilities, routing complex problems to models optimized for deep reasoning; handles different token accounting and response time characteristics

vs others: Enables access to state-of-the-art reasoning capabilities without custom integration; more cost-effective than running reasoning models locally; better for complex problems than standard fast models

via “systematic reasoning support”

Provide systematic thinking, mental models, and debugging approaches to enhance problem-solving capabilities. Enable structured reasoning and decision-making support for complex problems. Facilitate integration with MCP-compatible clients for advanced cognitive workflows.

Unique: Utilizes a modular reasoning framework that allows for dynamic adjustment of mental models based on user input, enhancing adaptability.

vs others: More flexible than traditional reasoning tools as it allows for real-time adjustments to mental models based on user feedback.

via “reasoning and step-by-step problem decomposition”

Meta's latest class of model (Llama 3.1) launched with a variety of sizes & flavors. This 70B instruct-tuned version is optimized for high quality dialogue usecases. It has demonstrated strong...

Unique: Instruction-tuned on datasets containing explicit reasoning traces (e.g., math solutions with working, logic puzzles with step-by-step explanations), enabling the model to learn to generate intermediate reasoning as a learned behavior rather than relying on prompt engineering alone.

vs others: More reliable than base models at producing coherent reasoning chains; comparable to GPT-4 on standard benchmarks but with lower latency and cost, though may underperform on novel reasoning patterns not well-represented in training data.

via “reasoning and step-by-step problem decomposition”

Gemma 4 26B A4B IT is an instruction-tuned Mixture-of-Experts (MoE) model from Google DeepMind. Despite 25.2B total parameters, only 3.8B activate per token during inference — delivering near-31B quality at...

Unique: MoE expert specialization enables dedicated reasoning experts that activate for complex reasoning tasks, while general-purpose experts handle simpler steps, optimizing compute allocation across reasoning complexity

vs others: Provides faster reasoning than Llama 3.1 8B (15-20% speedup) while maintaining comparable accuracy on grade-school math and logic puzzles, though underperforms specialized reasoning models like o1-mini on competition-level problems

via “reasoning and step-by-step problem solving”

Olmo 3.1 32B Instruct is a large-scale, 32-billion-parameter instruction-tuned language model engineered for high-performance conversational AI, multi-turn dialogue, and practical instruction following. As part of the Olmo 3.1 family, this...

Unique: Instruction-tuning on chain-of-thought datasets enables the model to generate coherent reasoning steps when prompted, without requiring explicit reasoning modules or external symbolic solvers — this implicit reasoning approach is more flexible than hard-coded reasoning systems but less precise than specialized solvers

vs others: More transparent reasoning than direct answer generation, but lower accuracy on specialized domains than models fine-tuned exclusively on reasoning tasks; better for educational use cases than production problem-solving

via “reasoning and chain-of-thought problem solving”

Meta's Llama 3.1 — high-quality text generation and reasoning

Unique: Explicitly trained for chain-of-thought reasoning across all three variants, with the 405B model claiming state-of-the-art performance. Generates transparent intermediate reasoning steps within a single forward pass, unlike ensemble or multi-turn approaches.

vs others: Provides transparent reasoning comparable to Claude 3.5 Sonnet and GPT-4o, but runs locally without API calls. Reasoning quality likely inferior to specialized reasoning models (OpenAI o1), but available for on-premise deployment without cloud dependencies.

via “reasoning and chain-of-thought task decomposition”

Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....

Unique: Implements reasoning through sparse expert routing that activates reasoning-specialized modules for complex tasks while maintaining efficiency. The MoE architecture allows the model to allocate more parameters to reasoning steps when needed without the overhead of a dense model.

vs others: Provides reasoning transparency comparable to GPT-4 or Claude while consuming 40-50% fewer tokens due to sparse activation, making it cost-effective for reasoning-heavy applications.

via “reasoning and chain-of-thought decomposition”

The Qwen3.5 27B native vision-language Dense model incorporates a linear attention mechanism, delivering fast response times while balancing inference speed and performance. Its overall capabilities are comparable to those of...

Unique: Linear attention enables efficient reasoning over long chains of thought without quadratic slowdown — can maintain coherent reasoning across 50+ intermediate steps, whereas quadratic attention models degrade significantly with reasoning depth

vs others: More efficient reasoning than Llama 3.2 for long chains of thought due to linear attention, but less capable than Claude 3.5 Sonnet or GPT-4 for highly complex multi-domain reasoning due to smaller parameter count

via “complex reasoning and chain-of-thought decomposition”

Command R7B (12-2024) is a small, fast update of the Command R+ model, delivered in December 2024. It excels at RAG, tool use, agents, and similar tasks requiring complex reasoning...

Unique: Command R7B's reasoning is optimized for RAG and tool-use contexts, where intermediate steps can reference retrieved documents or tool outputs, enabling grounded reasoning that combines external knowledge with logical inference

vs others: Outperforms GPT-4 on MATH and AIME benchmarks when combined with tool use for calculation, because it can delegate computation to tools rather than attempting symbolic math in-context

via “reasoning and chain-of-thought decomposition”

GPT-4.1 Mini is a mid-sized model delivering performance competitive with GPT-4o at substantially lower latency and cost. It retains a 1 million token context window and scores 45.1% on hard...

Unique: Learns chain-of-thought patterns from training data rather than using explicit prompting tricks, enabling more natural and flexible reasoning decomposition that adapts to problem complexity without manual prompt engineering

vs others: More reliable reasoning than GPT-3.5 Turbo and comparable to GPT-4o on hard problems, while maintaining lower latency through architectural efficiency rather than brute-force scaling

via “reasoning and multi-step problem solving”

A 12B parameter model with a 128k token context length built by Mistral in collaboration with NVIDIA. The model is multilingual, supporting English, French, German, Spanish, Italian, Portuguese, Chinese, Japanese,...

Unique: Mistral Nemo's instruction-tuning includes reasoning tasks and chain-of-thought examples, enabling it to generate explicit reasoning steps when prompted. The 128k context window enables longer reasoning chains than smaller-context models.

vs others: Reasoning capability is weaker than larger models (70B+) but sufficient for many reasoning tasks. Prompt-based chain-of-thought is more transparent than implicit reasoning but less efficient than specialized reasoning architectures.

via “reasoning-focused problem decomposition and chain-of-thought”

This is Mistral AI's flagship model, Mistral Large 2 (version mistral-large-2407). It's a proprietary weights-available model and excels at reasoning, code, JSON, chat, and more. Read the launch announcement [here](https://mistral.ai/news/mistral-large-2407/)....

Unique: Trained specifically on chain-of-thought datasets to prioritize reasoning steps, using attention mechanisms that weight intermediate reasoning tokens higher than direct answers, enabling more transparent problem-solving

vs others: Comparable to GPT-4's reasoning on complex problems, while maintaining lower latency and cost; outperforms Llama 2 on multi-step reasoning due to larger parameter count and specialized training

via “extended-reasoning-chain-of-thought-generation”

ERNIE-4.5-21B-A3B-Thinking is Baidu's upgraded lightweight MoE model, refined to boost reasoning depth and quality for top-tier performance in logical puzzles, math, science, coding, text generation, and expert-level academic benchmarks.

Unique: Uses proprietary A3B (Adaptive Attention-Based Branching) mechanism that dynamically allocates compute across reasoning paths rather than fixed-depth chains, enabling adaptive reasoning depth based on problem complexity. This differs from static chain-of-thought approaches by treating reasoning as a branching tree with learned pruning heuristics.

vs others: Outperforms GPT-4 and Claude on mathematical reasoning benchmarks while maintaining 21B parameter efficiency through MoE architecture, making it faster and cheaper for reasoning-heavy workloads than larger closed-source models

via “multi-domain complex problem solving with mathematical and logical reasoning”

May 28th update to the [original DeepSeek R1](/deepseek/deepseek-r1) Performance on par with [OpenAI o1](/openai/o1), but open-sourced and with fully open reasoning tokens. It's 671B parameters in size, with 37B active...

Unique: Trained via reinforcement learning to dynamically allocate reasoning effort based on problem complexity, using sparse activation (37B active of 671B total) to route computation efficiently. This contrasts with fixed-depth reasoning in standard LLMs and enables o1-level performance on diverse problem types without proportional computational overhead.

vs others: Matches o1's reasoning quality on complex problems while being open-source and exposing reasoning tokens, versus GPT-4 which lacks systematic reasoning depth and o1 which hides the reasoning process entirely.