Build mode

Build mode is Contral's AI coding agent. You describe what you want, and Contral reads your project, proposes edits, runs commands with your permission, and explains every change with a teaching card.

Opening Build mode#

• In the extension: click the Contral icon in the activity bar, or run Contral: Open Build Agent from the Command Palette.
• If you're in Learn mode, switch back with the Build/Learn toggle at the top of the Contral panel.
• In VS Code's own Chat view you can also type @contral /build <request> to hand a task to the Build agent in Fast mode.

The Contral panel has tabs along the bottom: Chat, Plan, Changes, Runs, Learn and Codebase.

Giving Contral a task in Build mode#

1. Open a folder or workspace. Contral works on the files in that workspace.
2. Pick an agent mode in the prompt row: Fast, Plan, Deep or Recursive. See Agent modes.
3. Type your request and press Enter. Be specific about the outcome, for example "Add input validation to the signup form and show an error under each field."
4. Contral reads the relevant files, then proposes changes.

You can attach images (such as a screenshot of an error or a design) when the selected model supports image input.

Reviewing Contral's edits before they land#

Contral never writes to your files silently. Proposed edits appear as a review card, split into hunks (blocks of changed lines):

• Accept or skip each hunk individually.
• Click Apply all (or Apply N selected) to write the changes, or Skip all to discard them.
• Risky hunks are flagged with "verify this" so you look at them closely.

After applying, each change gets a teaching card explaining what it does and why it's written that way.

Commands Contral runs in your terminal#

When the agent needs to run a command (install packages, run tests, start a dev server), it asks first: "Build Agent wants to run: {command}" with Run and Skip.

Some commands are always refused for safety, including sudo, piping downloads into a shell (curl … | sh), rm -rf, dd, mkfs and command substitution. You'll see "Refused to run blocked command".

When you ask Contral to scaffold a new project (for example a Next.js, Vite, Express, FastAPI, Flask, Django or Go app), it auto-approves the standard install and dev-server commands so the project comes up quickly. Turn this off with the contral.build.autoApproveScaffold setting. Contral opens a live preview of web projects automatically; turn that off with contral.build.autoPreview.

Auto-fix in Build mode#

If a scaffolded project fails to build, Contral reads the error and tries to fix it automatically, up to three rounds. Auto-fix is included on every plan.

Undoing a Build turn#

Run Contral: Rewind a Build turn from the Command Palette to restore your files to how they were before a Build turn. Contral keeps checkpoints for your most recent 25 turns in the current editor session. Checkpoints don't survive restarting the editor, so commit to git before big changes.

Build sessions#

Each Build conversation is a session with its own history, memory and plan. Type /new to start a fresh session and /clear to clear the current one. Long sessions can be summarized with /compact to keep the model focused. See Slash commands reference.

What Build mode counts against your plan#

Each message you send to the Build agent with Contral's hosted models uses one AI message from your daily allowance. Recursive mode also uses one recursive run. Messages sent with your own API key count as BYOK messages instead. Slash commands don't count. See Usage limits & quotas explained.

Build mode settings#

Change settings in your editor's Settings UI (search for "Contral").