Claude Code

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Quick start

Install and sign in

curl -fsSL https://nexus.fireworks.ai/install.sh | bash

Requires Node.js 18 or later, git, and bash. On Windows, run it from Git Bash; PowerShell breaks the script’s line endings.

nexus login

Sign in with your browser, or paste a Fireworks key.Already set up? Skip to step 2.

Connect Claude Code

nexus claude
nexus claude status

Nexus CLI selects Nexus Auto by default. To choose another model, pass --model:

nexus claude --model glm-5p3-flash

--model sets the default model for new sessions and adds it to /model. /model also lists the Fireworks catalog and an Auto row for Nexus Auto (auto). Your own picker rows are not changed. Set effort in that same picker.To send one Anthropic model tier or your subagents to a specific model, pin that slot:

nexus claude --sonnet deepseek-flash-latest --subagent deepseek-flash-latest

Tier flags are --opus, --sonnet, --haiku, --fable, and --subagent. Unpinned slots stay on Claude Code’s defaults. Running nexus claude again keeps your pins. Pass native, such as --sonnet native, to release a slot.

Restart and pick a model

Start a new session, or exit and run claude --resume <id>. Open /model:

nexus claude status shows the provider, where the key comes from, and the configured model.

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Use Nexus Auto

• Anthropic model turns: your Claude login (OAuth), or an exported ANTHROPIC_API_KEY.
• OpenAI model turns: connect an OpenAI Provider Key. Nexus CLI doesn’t send a key from --openai-api-key or nexus configure on auto. See how auto picks its closed model.
• Manual setup: send x-anthropic-api-key and x-openai-api-key headers yourself. See Manual setup (advanced).

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MCP and tools

claude mcp list
# docs: npx -y your-mcp-server - ✔ Connected

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Usage and cost

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Troubleshooting

• Upgrading from an earlier version? See Upgrading from earlier versions.
• Text-only models fail on pasted images. Use /rewind, or switch to a vision model such as glm-5p3-flash.
• Resume or restart the session after changing models.
• Auto mode says classifier requests are billed: this is expected, once per session, and auto mode keeps working. Its safety checks run on your Sonnet slot and bill to Anthropic. To bill them at Fireworks rates, pin Sonnet with nexus claude --sonnet <id>.

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Manual setup (advanced)

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.fireworks.ai/inference",
    "ANTHROPIC_AUTH_TOKEN": "fw_YOUR_FIREWORKS_API_KEY",
    "ENABLE_TOOL_SEARCH": "true"
  },
  "model": "glm-latest"
}

export ANTHROPIC_BASE_URL="https://api.fireworks.ai/inference"
export ANTHROPIC_API_KEY="$FIREWORKS_API_KEY"
claude --model glm-latest

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What the Nexus CLI writes

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.fireworks.ai/inference",
    "ANTHROPIC_CUSTOM_HEADERS": "X-Fireworks-Api-Key: fw_...",
    "DISABLE_TELEMETRY": "1",
    "DO_NOT_TRACK": "1",
    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1",
    "CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING": "1",
    "CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE": "0",
    "ENABLE_TOOL_SEARCH": "true"
  },
  "modelPicker": {
    "options": [
      { "model": "auto[1m]", "label": "Auto" }
    ]
  },
  "model": "auto[1m]",
  "statusLine": { "type": "command", "command": "... claude-statusline.mjs" }
}

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Claude Agent SDK

nexus claude --model auto