# Category 06 — Chain of Thought Reasoning

*Last updated: April 2026. Content reflects April 2025–April 2026; older material is contextualized as historical.*

This category covers how large language models reason — and how that reasoning is shaped, surfaced, and made legible to humans. It spans foundational academic work (CoT, ToT, GoT, ReAct, Reflexion, process rewards), the 2024–2026 wave of RL-trained reasoning models (o1, o3/o4-mini, GPT-5, DeepSeek-R1, Kimi k1.5/K2, Qwen3), commercial product decisions about visibility and pricing of "thinking," the open-source frameworks that expose reasoning as a first-class API surface, and the practitioner folklore about which prompting moves still work and which have been obsoleted by models that already reason internally. The thread running through all five angles for the Unslop project: reasoning traces are the most powerful humanization surface in modern AI, and the industry has not solved how to make them sound like a person wrote them.

## Angle files

- [A-academic.md](./A-academic.md) — 29 foundational and frontier papers: Wei 2022 CoT, Kojima zero-shot CoT, Self-Consistency, Tree of Thoughts, Graph of Thoughts, ReAct, Reflexion, Self-Refine, PAL/PoT, Least-to-Most, STaR, process reward (Uesato, Lightman/PRM800K), scratchpads (Nye), faithfulness (Turpin, arXiv 2503.08679), emergent abilities, o1 System Card, DeepSeek-R1, QwQ-32B, Kimi k1.5, Li et al. System-1→System-2 survey, s1 budget forcing (Muennighoff 2025), CoT Monitorability (Korbak 2025), Coconut latent reasoning (ICLR 2025), Wharton "Decreasing Value of CoT" (Jun 2025), arXiv 2503.08679 empirical faithfulness, and the Latent CoT Survey (May 2025).
- [B-industry.md](./B-industry.md) — 22 posts from OpenAI, Anthropic, Google DeepMind, Meta FAIR, Hugging Face, and independent essayists (Lilian Weng, Sebastian Raschka, Nathan Lambert, Jay Alammar, Simon Willison) on the framing war over visible vs. hidden CoT, the R1 recipe, the faithfulness problem as labs see it, the "reason privately, humanize publicly" pattern that has become canonical, GPT-5 unified reasoning (Aug 2025), Claude 4 adaptive thinking, o3/o4-mini (Apr 2025), and OpenAI's CoT monitorability safety post.
- [C-opensource.md](./C-opensource.md) — 22 repositories: canonical paper implementations (ToT, GoT, ReAct, Reflexion), agent frameworks (LangGraph ~28.7k+ stars, DSPy, CrewAI ~48k+ stars, LlamaIndex, AutoGen, OpenAgents), open-weights reasoning models (DeepSeek-R1 ~92k+ stars, Kimi K2 Thinking 1T-param MoE), budget-forcing implementation (s1/simplescaling), latent reasoning (facebookresearch/coconut), and the 2025 RL-reproduction wave (Open-R1, TinyZero, SimpleRL-Zoo, Open-Reasoner-Zero, PRM800K, PRIME).
- [D-commercial.md](./D-commercial.md) — 16 products across reasoning-native APIs (OpenAI o1/o3/o4-mini/GPT-5, Anthropic Claude 4 with Adaptive Thinking, Gemini Deep Think, DeepSeek Reasoner, Grok 4.20), reasoning-optimized platforms (Perplexity, You.com, Phind, Consensus), and agent-reasoning systems (Devin, Reflection AI Asimov, Adept, Lindy, Relevance AI), with pricing snapshots, transparency postures, and humanization gaps per product. New for 2025: GPT-5 opaque routing, adaptive thinking replacing `budget_tokens`.
- [E-practical.md](./E-practical.md) — 23 high-signal community threads and reports from r/LocalLLaMA, r/ChatGPTPromptGenius, r/PromptEngineering, HN, and the OpenAI Developer Forum: the "magic phrase" tradition, the empirical backlash against CoT on modern reasoning models (Wharton Jun 2025), the convergent "Wait… Hmm… Actually…" voice, reasoning-budget hacks, faithfulness anxiety, Karpathy's IQ-vs-EQ split, and the "CoT is a mirage" critique (Aug 2025).

## Synthesis and legacy

- [SYNTHESIS.md](./SYNTHESIS.md) — the distilled synthesis across all five angles
- [INDEX.md](./INDEX.md) — legacy category summary — superseded by SYNTHESIS.md, preserved for traceability
