AI Codex
Foundation Models & LLMs

Large Language Model

Also: LLM

The technology behind AI tools like Claude, ChatGPT, and Gemini. An LLM is a type of AI trained on enormous amounts of text — books, websites, articles, code — until it learned to read, write, summarize, answer questions, and hold conversations. The 'large' refers to the scale of training and the model's internal complexity, not something you interact with directly. When people say 'AI,' they usually mean an LLM.

In practice

When you type a message to Claude and it writes back a coherent, relevant response — that's a large language model at work. It's software trained on enormous amounts of text until it learned to read, write, reason, and converse. The "large" refers to scale of training, not something you see directly. Claude, GPT-4, and Gemini are all LLMs.

Related concepts

Where Large Language Model shows up

5 articles

Opus 4.7 has five API breaking changes that will return 400 errors on existing code. Here's each one, the fix, and the full migration checklist. Also: Sonnet 4 and Opus 4 retire June 15, 2026.

Implementation guide·Migrating from Claude Opus 4.6 to Opus 4.7: the breaking changes·7 min

You've heard about AI. You've maybe tried it once, got something weird, and closed the tab. This is the honest version of what it is, why most people's first attempts disappoint them, and what to actually do.

Role-Specific·New to AI? Start here.·8 min

Anthropic's flagship model gets a significant upgrade — better software engineering, 3.75-megapixel vision, and a new xhigh effort level. Pricing is unchanged. There are API breaking changes versus Opus 4.6.

Role-Specific·Claude Opus 4.7: what's new and what the API changes mean·8 min

A large language model is what Claude is at its core — and understanding how it works changes how you think about everything else in AI.

Core Definition·The engine under everything·5 min

Anthropic's new tool lets you create prototypes, slide decks, one-pagers, and full design systems by describing what you want. Output is exportable as PDF, URL, or PPTX and can connect to your existing design files. Available in research preview for Pro, Max, Team, and Enterprise.

update·Claude Design: from description to visual in one conversation·5 min