Using Cosindra from VS Code or Cursor

Install

• •VS Code: search for “Cosindra” in the Extensions view, or install from the Visual Studio Marketplace.
• •Cursor: search for “Cosindra” in Cursor’s Extensions view, or install from Open VSX. Cursor does not use Microsoft’s Marketplace.
• •The folder you open must be trusted (Workspace Trust). In a restricted workspace the extension does not activate, because it starts a local process and writes into your project.

The flow

1. Open the Cosindra panel in the activity bar and click Sign in, by password or with Google or GitHub. Signing in downloads the local server for your platform into the Cosindra data folder; the panel shows progress and lets you cancel.
2. Click Set up project. The extension looks for a .uproject in the open folder and its parents, asks if there are several, detects the engine version and installs the matching prebuilt CosindraMCP plugin into Plugins/. No compiler, no rebuild. Do this with the Unreal Editor closed: the extension refuses to replace a plugin the editor is holding open.
3. Accept the offer to open the editor, or click Open Unreal Editor later. The editor’s Output Log shows CosindraMCP: Connected to MCP Server! once the plugin reaches the local server.
4. Ask your agent for something in the open level. The panel shows what is ready and what still needs a click.

Connecting each agent

• •GitHub Copilot (VS Code): nothing to do. The extension registers the Cosindra MCP server through VS Code’s own API, so agent mode lists the Unreal tools as soon as set-up is done. Ask mode does not call tools.
• •Cursor’s agent: click Add MCP Server to Cursor in the panel. Cursor opens its own confirmation dialog with the entry prefilled; confirm once. If you prefer a file, the same action can write ~/.cursor/mcp.json after asking.
• •Claude Code: click Connect Claude Code or Codex. It offers to write the server entry into the project’s .mcp.json, which Claude Code reads on its next start. It also shows the equivalent claude mcp add one-liner.
• •Codex: the same command shows the exact entry for Codex’s configuration. Codex reads its own config, never the editor’s.

Every entry points at a small launcher command rather than a port, so the local server can restart or move ports without any agent losing the connection.

Where things go

• •Cosindra data folder: ~/Library/Application Support/Cosindra on macOS, %LOCALAPPDATA%\Cosindra on Windows. It holds the local server (bin/), its discovery files and the logs.
• •Your project: Plugins/CosindraMCP/ and an enabled plugin entry in the .uproject. Optionally .mcp.json beside it, only if you asked for Claude Code.
• •Your account: credentials live in the operating system keychain, never in a settings file.
• •Settings: cosindra.showStatusBar toggles the status bar item. cosindra.cloudApiUrl exists for development only and accepts nothing but cosindra.ai over https or a loopback address.

Desktop app and extension together

Both are clients of one per-user local server. Whichever starts first starts the server; the other finds it. Quitting the desktop app does not stop a session an agent in your editor is using, and the server retires on its own when nothing is connected.

Plans

The extension is free to install. Driving Unreal from an external AI agent needs a paid plan or the ten-day trial that every new account gets without a card. A tool call from an account without either answers with an upgrade message instead of running; see the pricing page.

If something does not connect

• •Run Cosindra: Show Connection Status from the command palette. It says what the extension currently sees: server, project, editor, sign-in.
• •Open View → Output → Cosindra. The same lines go to logs/extension.log in the Cosindra data folder, next to the local server’s own logs/debug_*.log.
• •An agent that “sees no tools” is almost always reading its own configuration: for Claude Code and Codex run Connect Claude Code or Codex again and restart the agent; for Cursor confirm the MCP entry is present in Cursor’s MCP settings.
• •If the MCP server itself fails to start, the editor’s own MCP output channel shows the launcher’s message.
• •Still stuck? In the panel open Details → Copy diagnostics: it puts versions, connection state and the last 200 log lines on your clipboard with tokens removed. Paste it into a message on the contact page.