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Claude Code is Anthropic’s agentic coding tool. It reads your whole repository, plans and applies changes across files, runs commands and tests, and iterates on failures. It runs in the terminal, as a VS Code extension, and as a plugin for PyCharm, IntelliJ and the other JetBrains IDEs. It ships with built-in gateway support, so pointing ANTHROPIC_BASE_URL at Opper runs the same harness on any model in the catalog, not just Claude.

Setup

Install Claude Code first if you don’t have it: follow Anthropic’s setup guide for macOS, Linux or Windows.
One command, no config files:
The first run opens the browser to sign in with Opper. It sets ANTHROPIC_BASE_URL and ANTHROPIC_AUTH_TOKEN for the session and starts Claude Code. Pin a model with --model <id>.
To connect it permanently instead, put your Opper key in Claude Code’s settings file: ~/.claude/settings.json for all projects, or .claude/settings.local.json inside one project.
Create a key under API keys. The last line fills the /model picker with Opper models. The terminal, VS Code and JetBrains IDEs all read this file. Use the project file if other projects should keep using your own Anthropic account; it is ignored by git. Run /status inside Claude Code to check: the base URL should point at api.opper.ai.

VS Code

Install Claude Code for VS Code (by Anthropic) from the Extensions view, add the settings file above, and reload the window.

PyCharm, IntelliJ and other JetBrains IDEs

Install Claude Code [Beta] (by Anthropic) from the plugin Marketplace. Then either add the settings file above, or set Settings → Tools → Claude Code [Beta] → Claude command to opper launch claude (after npm i -g @opperai/cli). If the IDE says the command is not found, use the full path that which opper prints.

Choose a model

Type /model to pick from the Opper models (listed as “From gateway”), or pass a full ID from the catalog, such as /model anthropic/claude-sonnet-5-5. A dynamic route works the same way, dynamic/<route-name>, with a key from the organization that owns the route.
/model saves the choice in ~/.claude/settings.json, so later sessions that do not go through Opper try to use it too and fail with “There’s an issue with the selected model”. If you use Opper only in some projects or through opper launch, set "ANTHROPIC_MODEL" in the env block or pass --model instead.

Windows

The same setup works on Windows. The user settings file is %USERPROFILE%\.claude\settings.json, and where opper gives the full path for the JetBrains Claude command.

Troubleshooting

  • /status does not show Opper. The settings file was not read: check the JSON, then restart the session or reload the window. A project’s .claude/settings.local.json wins over ~/.claude/settings.json.
  • Old model names in the picker, or no Opper models. The IDE is running an old Claude Code. An IDE started from the Dock or Start menu can find a different claude than your terminal; compare claude --version with /status.
  • opper launch claude does not open the browser. It skips sign-in when you are already signed in or OPPER_API_KEY is set, and uses that key. opper whoami shows which.

Full guide

Model alias mapping, CI usage, EU-only routing and migrating from OpenRouter are in the dedicated guide:

Run Claude Code on any model

Manual setup, alias mapping, per-project config, CI, and troubleshooting.

Claude Desktop

The same agent inside Anthropic’s desktop app.

All apps

Every app that runs on Opper.
Last modified on November 5, 2026