Key Terminology
The 15 words you need before reading anything about AI coding.
AI tooling has a lot of jargon. Master these and documentation becomes easy.
- LLM β large language model (Claude, GPT, Gemini, Llama, Hermesβ¦).
- Prompt β the text you send to a model.
- Context window β how much the model can see at once.
- Agent β a program that uses an LLM to choose actions and execute them in a loop.
- Tool / function calling β letting the model invoke code (edit a file, query a DB, browse the web).
- MCP β Model Context Protocol, an open standard for connecting tools and data to AI apps.
- Token β a chunk of text the model processes; models bill by tokens.
- Inference β running the model to produce output.
- Model β a specific trained network (e.g.
claude-3-5-sonnet). - Provider / API β a service that runs models for you (Anthropic, OpenAI, Google, Groq).
- Local model β a model running on your own machine (via Ollama, LM Studio).
- Hallucination β confident but wrong output.
- RAG β retrieval-augmented generation: searching documents and injecting them into context.
- System prompt β fixed instructions that steer the model for the whole session.
- Sandbox β an isolated environment where an agent can run untrusted commands safely.
Example
Prompt: "Fix the null-check bug in utils.js"
System prompt: "You are a careful senior engineer. Prefer small diffs."
Context: [utils.js contents, failing test output]
Tool calls: read_file(utils.js) β edit_file(...) β run_tests()
That one-liner prompt, plus context and tools, is the entire recipe behind a coding agent.