Look up any term in AI.
Definitions that explain the actual mechanism — not a paraphrase of the name. Written for people who have to build with this, or decide about it.
Glossary
256 terms, each with a worked definition, how it actually works, and where it breaks.
Browse A–ZModels
What each model is good at, what it costs per token, and when the size matters.
Compare modelsAI tools
68 tools across 11 categories, with pricing and status kept current.
Browse the directoryExplainers
Longer pieces on the things a definition cannot hold: benchmarks, costs, and claims worth checking.
Read the blogStart with the load-bearing ideas
The terms the rest keep referring back to. Read these and most AI writing stops being opaque.
Graph Neural Networks (GNN)
A GNN takes adjacency as data, not as an architectural assumption. Message passing worked by hand, why k layers reach d^k nodes, and why deep GNNs collapse.
Inference
Running a trained model to get an answer. Training is paid once; inference is paid on every request — and it is where most AI money goes.
Positional Encoding (RoPE)
Positional encoding tells a transformer where each token sits in a sequence. Why self-attention needs it, and how rotary embeddings (RoPE) work.
Neural Network
Why a stack of layers does what one cannot: two linear layers collapse into a single matrix, and a hidden layer of two units solves XOR.
Naive Bayes
A probabilistic classifier applying Bayes' theorem under a deliberately false feature-independence assumption — fast, data-light, a strong text baseline.
Residual Connections (Skip Connections)
Residual connections add a block's input back to its output — F(x) + x — the trick that lets gradients flow through deep nets and made transformers trainable.
Recently updated tools
Every listing carries a status. When a product is renamed, sunset or acquired, the page says so.
AgentGPT
Reworkd AI · Web Application
Open-source, browser-based autonomous AI agent from Reworkd. You name a goal, the agent plans tasks, executes them, and learns from the results.
FreemiumDola (formerly Cici)
ByteDance · Web, Mobile & Desktop Application
ByteDance's overseas AI assistant, renamed from Cici in November 2025. Free chat, translation and image generation, region-locked out of the US and China.
FreeKimi Code
Moonshot AI · CLI Tool & Editor Integration
Moonshot AI's open-source terminal coding agent: an MIT-licensed CLI with MCP and editor integration, driving Kimi K3 and K2.7 Code via Kimi membership.
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