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Nexus CLI runs Claude Desktop’s Chat, Cowork, and Code on Fireworks models. It runs on macOS and Linux and needs a stored credential from nexus login. Linux support is unofficial: Anthropic documents third-party mode for macOS and Windows, but the Linux build uses the same mechanism. On Linux, on needs a systemd user session. Quit and reopen Claude Desktop after on or off. Preview Anthropic Messages Native web search macOS and Linux Claude Desktop has no manual setup. Use the Nexus CLI.

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Quick start

Install and sign in

Requires Node.js 18 or later, git, and bash. On Windows, run it from Git Bash; PowerShell breaks the script’s line endings.
Sign in with your browser, or paste a Fireworks key.Already set up? Skip to step 2.

Connect Claude Desktop

Reopen and pick a model

Reopen Claude Desktop. The picker starts on auto, followed by the Fireworks models, in place of your claude.ai subscription models.
Claude Desktop model picker in Cowork showing Auto selected, then Kimi K3 Fast, Kimi K3, MiniMax M3, GLM 5.3 Fast, GLM 5.3, and DeepSeek V4.1 Flash

Claude Desktop after Nexus CLI, with Auto selected

The picker starts on auto, followed by the Fireworks models.
off puts your previous setup back, including your claude.ai models.

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Use Nexus Auto

The picker lists auto and the Fireworks models. In Claude Desktop, auto uses Fireworks open models only, and there’s no local provider key to set. To pick between Anthropic models and open models for each turn, use Nexus Auto in Claude Code.

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MCP and tools

Third-party mode hides the in-app connector browser, so you manage connectors with Nexus CLI. See Connectors. Native web search is supported while connected through Nexus CLI. Fireworks runs the search server-side and returns the results, with no MCP server or search service to set up.

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Connectors

Claude Desktop’s third-party mode hides the in-app connector browser. Manage connectors with Nexus CLI instead:
  • on imports the connectors you already use, from Desktop session history, your previous Desktop config, and your claude.ai organization’s connector registry.
  • mcp sync also adds connectors from your claude.ai organization when the Claude Code CLI is installed and signed in, plus any you added later. Run nexus claude-desktop mcp sync when you add a connector later and want it in third-party mode too.
  • nexus claude-desktop mcp add <name> <url> and mcp remove <name> manage entries by hand. Removals stick across syncs.
  • Each connector asks you to sign in once the first time you use it after on.
  • Connector OAuth clients you register are saved in ~/.nexus/claude-desktop/oauth-clients.json, readable only by you. They survive off and on.
MCPs that need an OAuth client ID and secret do not move. If you need one of these connectors, reach out to the team. Google-hosted connectors (Gmail, Google Drive, Google Calendar, BigQuery) need a Google OAuth client you own, created as a Desktop app client in Google Cloud. One client covers all four:
The hosted Figma connector does not work in third-party mode. Turn on the Figma desktop app’s local server in Dev Mode, then run nexus claude-desktop mcp add figma-desktop http://127.0.0.1:3845/mcp.

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Skills and plugins

on copies your custom skills and plugins once. Run nexus claude-desktop on again to copy ones you add later. Changes you make while connected do not copy back.

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What stays with your claude.ai subscription

Third-party mode does not show your claude.ai chats, projects, artifacts, memory, or scheduled tasks. Nothing is deleted. Run nexus claude-desktop off and reopen Claude Desktop to get them back. New work while connected:
  • Chats, projects, artifacts, and memory save only on this computer. They do not appear on claude.ai web or mobile, and you cannot share them.
  • Scheduled tasks run only while the computer is awake. A missed run starts when it wakes.
  • Chat cannot search past chats and does not get nightly memory summaries. Chat uses memory only inside a project.
  • Voice mode is not available.
Anthropic lists these limits in its third-party feature matrix and local data guide.

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Troubleshooting

  • status shows the local gateway is not responding: run nexus claude-desktop on to restart it.
  • Models are missing from the picker: run on once while online, then restart Claude Desktop.
  • The Code tab says the API key was rejected: run on again to refresh the key from your stored credential.
  • A connector sign-in error won’t clear: mcp remove it, then mcp add it again with your own OAuth client (Google) or the local server (Figma).

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What the Nexus CLI writes

  • on writes a third-party inference provider profile, Claude Desktop’s own supported mechanism. The profile points at a small local gateway that Nexus CLI runs as a background service: a launchd agent on macOS, or a systemd user unit on Linux. It starts at login and restarts after a crash.
  • on copies your custom skills and plugins into third-party mode. It never overwrites a file that is already there. Conversations stay in the mode they were made in.
  • off restores your previous provider profile and the device settings Nexus CLI changed, then removes the local gateway service. Nothing of yours is deleted.