The Four AI Surfaces That Define Cursor: Tab, Chat, Composer and Agent Mode

Most new Cursor users only discover two of its four AI surfaces. The ones they miss are often the most powerful. Here is a complete breakdown of all four, what each does, and exactly when to reach for which.

Cursor is not one AI feature. It is four distinct AI surfaces, each optimised for a different kind of task, plus a newer fifth surface (Background Agent) that runs in the cloud. Understanding the distinction between them is the single most important step toward using Cursor well. Most people who feel they are "not getting much from Cursor" are simply using one surface for a job that another surface does far better.

Surface 1: Cursor Tab, the Predictive Engine

Cursor Tab runs on every keystroke. Unlike traditional autocomplete that suggests one word at a time, Tab anticipates multi-line edits across your current file, sometimes suggesting changes you have not yet started typing. It is always on, never consumes credits, and is the surface you interact with most often.

The defining behaviour: Tab suggests the next edit, not the next token. Add a field to a TypeScript interface and Tab will often propose related changes throughout the file, anticipating the coordinated edit you are making rather than just completing the current line.

Surface 2: Chat, the Codebase-Aware Conversation

Chat opens with Cmd+L (Ctrl+L on Windows). It is a conversational interface inside the editor where you ask questions about your code, request explanations, get debugging help, or discuss design decisions. What makes Cursor's Chat different from a generic AI chatbot is codebase awareness through the @ symbol, which lets you reference any file, folder or symbol in your project.

Use Chat when you want to understand, explain, debug or explore. The output is text in a panel that you might then act on yourself. Chat is for thinking; the other surfaces are for doing.

Surface 3: Composer, the Multi-File Editor

Composer opens with Cmd+I. It is the surface where you describe what you want done and the AI plans and executes changes across as many files as needed. Composer is what changed Cursor from "another AI editor" into "the AI editor." The ability to refactor a feature across twenty files from a single prompt was genuinely unprecedented when it shipped.

Use Composer when you want code changed in the editor. The output is real diffs in real files that you review and accept or reject. Chat plans; Composer executes.

Surface 4: Agent Mode, the Autonomous Tier

Agent Mode is the autonomous surface. You give the agent a goal ("add OAuth login with Google", "migrate from Express to Fastify", "fix all failing tests") and it plans, edits, runs commands, reads test output, iterates and reports back. Agent Mode is what makes Cursor agentic in the strong sense: it completes substantial multi-step work without per-edit approval.

The toggle for Agent Mode sits in the Composer panel. Once enabled, you describe goals rather than instructions, and the agent works toward them autonomously.

The Fifth Surface: Background Agent

The newest addition runs in the cloud rather than your local editor. Background Agent clones your repository to Cursor's servers, executes the task remotely, and opens a pull request when done. The benefit: you can fire off multiple background tasks in parallel and keep working in your IDE while they run.

How They Compose

The real power emerges when you combine surfaces. A typical workflow: use Chat to understand a problem and explore solutions, switch to Composer to make the changes, use Tab to refine the details as you review, and fire off Agent Mode or Background Agent for the larger autonomous chunks. Fluency means knowing instinctively which surface fits the task in front of you.