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AI & Automation

AI & Automation

Tools for estimating AI API costs, context windows, and LLM-facing content.

Tools

Comparisons

Guides

Glossary

Token

A token is the basic unit of text an LLM processes — roughly ¾ of a word for common English, though punctuation, numbers, and rare or technical words can each become their own token. Every API request is priced and limited by token count, not word or character count.

Context Window

The context window is the maximum number of tokens a model can process in a single request — the system prompt, conversation history, retrieved documents, the current message, and the model's own output all draw from this same shared budget. Content beyond the limit is truncated or the request is rejected.

System Prompt

A system prompt is a set of instructions sent with every request that defines how a model should behave — its role, tone, constraints, and output format — separate from the user's actual message. It counts against the same token budget as everything else in the request, so a longer system prompt leaves less room for conversation and output.

llms.txt

llms.txt is a plain markdown file placed at a website's root that gives AI systems a structured summary of the site's pages, similar to how a sitemap helps search engines. It was proposed by Jeremy Howard of Answer.AI as a lightweight convention AI crawlers can read instead of parsing full HTML.

Embedding

An embedding is a numerical vector representation of a piece of text, produced by an embedding model, that captures its meaning in a form that can be compared mathematically. Texts with similar meaning produce vectors that are close together, which is what makes semantic search and RAG retrieval possible.

Fine-Tuning

Fine-tuning is the process of further training an existing model on your own dataset of examples so it internalizes a task, format, or style without needing those instructions repeated in every prompt. It's billed separately from regular API usage, as a one-time training cost per token processed.

Vector Database

A vector database is a database purpose-built for storing embeddings and searching them by similarity rather than exact match — given a query vector, it returns the stored vectors closest to it in meaning. This is what makes semantic search and RAG retrieval fast at scale, where comparing a query against millions of vectors one by one would be too slow.