Cody (VS Code extension)

IDE companion for the Cody CLI. Lets Cody open files, read diagnostics, and show inline diffs directly in your editor instead of only in the terminal.

What it does

On activation, this extension starts a small local MCP server and writes a lockfile at ~/.cody/ide/<port>.lock describing how to reach it. When you run cody from this editor's integrated terminal, the CLI finds that lockfile, connects over an authenticated WebSocket, and calls back into the editor for:

• openFile — open a file, optionally with a text range selected
• getDiagnostics — read current LSP/compiler diagnostics for a file or the whole workspace
• openDiff — show a proposed change as a native diff view you can accept or reject
• close_tab / closeAllDiffTabs — close diff tabs the CLI opened

The connection is authenticated with a random per-session token generated at startup and checked on every WebSocket handshake (X-Cody-Ide-Authorization header) — nothing is exposed beyond localhost, and the lockfile (which contains that token) is written with 0600 permissions.

Status bar

While running, a status bar item shows the local port the IDE server is listening on. Click it (or run Cody: Show Status from the command palette) to confirm it's active.

Development

bun install
bun run build       # esbuild bundle to dist/extension.js
bun run typecheck    # tsc --noEmit
bun test test/       # protocol tests — spins up a real server, connects a
                      # real MCP client over a real WebSocket, and asserts
                      # on the exact wire shapes the CLI parses

src/mcpServer.ts, src/ideServer.ts, src/lockfile.ts, and src/wsTransport.ts have no dependency on the vscode module and are covered directly by test/protocol.test.ts. src/editorOpsVscode.ts is the only file that touches the real VS Code API; it implements the EditorOps interface from src/editorOps.ts that the MCP tool handlers are written against, so the protocol layer can be tested without a running VS Code instance.

Packaging

bun run package   # requires @vscode/vsce, produces a .vsix