# Code
> The editor with a language server, git and a terminal; the same editor that opens a game's or an app's Source.
*Picture: Kettle Cove Post's Source on the Games bench: its files grouped as Code, Design, Build and Data, Game.swift open with the card for catchItem over its code, Go to definition, 1 reference and Ask Robin about it, and the outline and No problems in this file on the right*
Code is the editor, git and a terminal. It shows once you turn on Settings › Developer tools ("A terminal under the work and editing in the code view. Off unless you turn it on.").
## The rail
- **Files**: the project's files, in the editor, with git.
- **Code**: the coding bench.
- **Screen**: drives any Mac app by its controls. It needs Accessibility permission, and Screen Recording for captures.
- **Terminal**: the project's terminal.
**New Claude Code** starts a chat that runs in the Claude Code you installed, with your own plan or key. It needs a project open. The other coding agents on your Mac are offered the same way: **New OpenCode**, **New Codex**, **New Cursor**.
**OpenCode** runs as the OpenCode you installed (from opencode.ai), with the model providers you signed it in to (`opencode auth login` in a terminal) and your own OpenCode setup; Robin reads none of your keys. Its words and each step it takes, a file read, a command run, show in the chat as they come; what it would ask in a terminal, it asks in the chat, as the mode chip says; **Stop** ends its turn and keeps what it had said. When OpenCode is not on your Mac, or has no sign-in for the provider its model needs, the chat says so in plain words with what to do, and its card’s **Sign in** opens `opencode auth login` in Robin’s terminal, where you choose the provider and give it your key yourself; then **Continue**.
## The editor
Tabs, an **Outline**, find and replace, **Rename** and references, **Save** and **Save all**. A game's or an app's Source opens in this same editor, with its colours. A note reads as a page, a check record as its checks, other data as an outline that folds, and every hex colour written in the code (`#rgb`, `#rrggbb`, `0x…`) shows as that colour. Without Developer tools, Source is read-only.
## Source, as an IDE
The code sits under one slim bar, with the files on one side and a column on the other: the file’s outline, which follows the caret, what Robin last wrote in it, and its problems, each a press to its line.
- **The file map** down the editor’s right edge shows what the file is made of: a band for each type and function, its colours as dots, a tick for each problem and Robin’s marks. Press or drag to go there.
- **What Robin wrote** is marked in the gutter. Rest on a mark for a card saying what was asked and when, with **Compare with before** and **Undo it**.
- **Go anywhere**: ⌘P a file, ⇧⌘O a name in this file, ⌘T a name in the project, ⌘L a line, ⇧⌘F words across the project. ⌃⌘← and ⌃⌘→ go back and forward through where you have been.
- The files show **Grouped** or as **Folders**. **Open in Xcode** (or Android Studio, or VS Code) opens the project in its own app.
## Language servers
Errors, completions and go to definition come from a language server, when one is on your Mac. The status bar names the one in use and how it is doing: ready, starting, or started again after a crash.
- **Hover** a name for its signature and documentation, and how many references it has.
- **Completion** as you type, or ⌃Space, with its documentation; ⇥ steps through the places a completion leaves to fill. Signature help shows as you type `(` and `,`.
- **Go to definition** (⌘-click or F12), **References** (⇧F12), and every other use of the name washed as the caret rests on it.
- **Rename** (F2) changes every file at once, as one step that ⌘Z undoes in all of them.
- **Quick fixes**: the gutter’s lightbulb, or ⌥↩, offers what the server can mend.
- **Format** the file (⇧⌥F) or the selection (⌃⇧I). Format on save is in Settings › Developer tools, off to start.
- **Problems** show as squiggles, a dot in the gutter and the worst one said at the end of its line, and in Source’s problems list.
- **Folding** from the gutter, or ⌥⌘← and ⌥⌘→. Inlay hints are in Settings › Developer tools, off to start.
Robin finds the servers here:
| Language | Server | How to get it |
| --- | --- | --- |
| TypeScript, JavaScript | The project's own TypeScript, run by Node, else `typescript-language-server` | Building the game or `npm install` puts TypeScript in the project; Node with `brew install node` |
| Swift | Xcode's `sourcekit-lsp` | `xcode-select --install` |
| C, C++, Objective-C | Xcode's `clangd` | `xcode-select --install` |
| C# | `csharp-ls` or OmniSharp | `brew install dotnet`, then `dotnet tool install -g csharp-ls` |
| Python | `pyright-langserver`, `basedpyright-langserver` or `pylsp` | `brew install pyright` |
| Go | `gopls` | `go install golang.org/x/tools/gopls@latest` |
| Rust | `rust-analyzer` | `rustup component add rust-analyzer` |
| Kotlin | `kotlin-lsp` or `kotlin-language-server` | `brew install kotlin-language-server` |
| JSON, CSS, HTML | `vscode-json-language-server` and its kin | `npm i -g vscode-langservers-extracted` |
| YAML | `yaml-language-server` | `npm i -g yaml-language-server` |
| Markdown | `marksman` | `brew install marksman` |
With no server, a file is still edited and coloured, and the status bar says which server is missing. **How to install** asks first, then runs the command in Robin’s terminal in the project’s folder, where you watch it; the file connects by itself once the server is there. Robin never installs one silently. GDScript’s server lives inside a running Godot and is not asked.
On any line: **Go to definition**, **References**, **Ask Robin about it**, **Ask Robin to fix it**, **Show the change** and **Undo what Robin wrote here**. If the file changed on disk too, choose **Keep mine** or **Take theirs**.
**Robin can do this too.** From the chat, Robin asks the same language servers where something is declared and used, what it is, and what errors a project has, through its code kit. It renames and formats too, in the file’s tab when it is open, so ⌘Z takes it back. When a server is missing it gives the same install line; only you can press **How to install**.
## Keys
| Key | What it does |
| --- | --- |
| ⌘S / ⌥⌘S | Save / save every file |
| ⌘W | Close the tab |
| ⌘P | Go to a file |
| ⇧⌘O | Go to a name in this file |
| ⌘T | Go to a name in the project |
| ⌘L | Go to a line (in Source) |
| ⇧⌘F | Find words across the project |
| ⌃⌘← ⌃⌘→ | Back, forward through where you have been |
| ⌘/ | Comment |
| ⌘D | Duplicate the lines |
| ⌥↑ ⌥↓ | Move the lines |
| ⇧⌘K | Delete the lines |
| ⌘] ⌘[ | Indent, outdent |
| ⌥⌘E | Select the next one the same |
| ⇧⌥F / ⌃⇧I | Format the file / the selection |
| ⌥↩ | Quick fixes at the caret |
| ⌥⌘F | Find and replace |
| ⌘G ⇧⌘G | Next, previous match |
| ⌃Space | Completion |
| F12, or ⌘-click | Go to definition |
| ⇧F12 | References |
| F2 | Rename, across files |
| ⌥⌘← ⌥⌘→ | Fold, unfold |