Claude Code

Use Claude Code with Lightweight to access every model through a single API key — no workaround flags needed.

Claude Code is Anthropic’s CLI coding agent. With Lightweight, you can run Claude Code against any model in the catalog — including OpenAI, Google, and xAI models — through the native Anthropic interface.

Lightweight’s Anthropic-compatible endpoint means Claude Code works natively — no workaround flags, no shims, no extra configuration needed.

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Setup

Set two environment variables to point Claude Code at Lightweight:

Bash / macOS / Linux

export ANTHROPIC_BASE_URL="https://api.lightweight.one/v1"
export ANTHROPIC_API_KEY="lw_sk_your-key-here"

Add these to your ~/.bashrc, ~/.zshrc, or ~/.profile to persist across sessions:

echo 'export ANTHROPIC_BASE_URL="https://api.lightweight.one/v1"' >> ~/.zshrc
echo 'export ANTHROPIC_API_KEY="lw_sk_your-key-here"' >> ~/.zshrc
source ~/.zshrc

PowerShell / Windows

$env:ANTHROPIC_BASE_URL = "https://api.lightweight.one/v1"
$env:ANTHROPIC_API_KEY = "lw_sk_your-key-here"

To persist across sessions, set them as system environment variables:

[System.Environment]::SetEnvironmentVariable("ANTHROPIC_BASE_URL", "https://api.lightweight.one/v1", "User")
[System.Environment]::SetEnvironmentVariable("ANTHROPIC_API_KEY", "lw_sk_your-key-here", "User")

Then launch Claude Code as usual:

claude

That’s it — Claude Code will now route all requests through Lightweight.

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Model Selection Overrides

By default, Claude Code uses its standard model selection. You can override which model is used for each role with environment variables:

Bash / macOS / Linux

# Use Opus 4.6 as the primary model
export CLAUDE_CODE_USE_BEDROCK=0
export CLAUDE_MODEL="claude-opus-4.6"

# Override the "big" model (Opus-class tasks)
export CLAUDE_OPUS_MODEL="claude-opus-4.6"

# Override the "mid" model (Sonnet-class tasks)
export CLAUDE_SONNET_MODEL="claude-sonnet-4.6"

# Override the "small" model (Haiku-class tasks)
export CLAUDE_HAIKU_MODEL="claude-haiku-4.5"

PowerShell / Windows

$env:CLAUDE_CODE_USE_BEDROCK = "0"
$env:CLAUDE_MODEL = "claude-opus-4.6"

# Override the "big" model (Opus-class tasks)
$env:CLAUDE_OPUS_MODEL = "claude-opus-4.6"

# Override the "mid" model (Sonnet-class tasks)
$env:CLAUDE_SONNET_MODEL = "claude-sonnet-4.6"

# Override the "small" model (Haiku-class tasks)
$env:CLAUDE_HAIKU_MODEL = "claude-haiku-4.5"

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Fast Mode with claude-opus-4.6-fast

Lightweight offers claude-opus-4.6-fast — an optimized routing configuration that delivers lower latency for Opus-class tasks. This is ideal for interactive Claude Code sessions where responsiveness matters.

Bash / macOS / Linux

export ANTHROPIC_BASE_URL="https://api.lightweight.one/v1"
export ANTHROPIC_API_KEY="lw_sk_your-key-here"
export CLAUDE_MODEL="claude-opus-4.6-fast"
export CLAUDE_OPUS_MODEL="claude-opus-4.6-fast"

PowerShell / Windows

$env:ANTHROPIC_BASE_URL = "https://api.lightweight.one/v1"
$env:ANTHROPIC_API_KEY = "lw_sk_your-key-here"
$env:CLAUDE_MODEL = "claude-opus-4.6-fast"
$env:CLAUDE_OPUS_MODEL = "claude-opus-4.6-fast"

claude-opus-4.6-fast uses the same model with optimized routing for faster first-token times. Same quality, lower latency.

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settings.json Alternative

If you prefer not to use environment variables, you can configure Claude Code via its settings.json file:

macOS / Linux

Edit ~/.claude/settings.json:

{
  "apiBaseUrl": "https://api.lightweight.one/v1",
  "apiKey": "lw_sk_your-key-here",
  "model": "claude-opus-4.6"
}

Windows

Edit %APPDATA%\claude\settings.json:

{
  "apiBaseUrl": "https://api.lightweight.one/v1",
  "apiKey": "lw_sk_your-key-here",
  "model": "claude-opus-4.6"
}

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Extended Thinking

Claude models accessed through Lightweight support extended thinking (chain-of-thought reasoning). When enabled, the model will reason through complex problems step by step before producing a response.

Extended thinking is automatically available when using Claude Code with Lightweight — no additional configuration is needed. Claude Code will use extended thinking when appropriate based on the complexity of your prompt.

Supported models:

• claude-opus-4.6
• claude-opus-4.6-fast
• claude-sonnet-4.6
• claude-sonnet-4.5

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Full Example

Here’s a complete setup for the best Claude Code experience with Lightweight:

Bash / macOS / Linux

# Core configuration
export ANTHROPIC_BASE_URL="https://api.lightweight.one/v1"
export ANTHROPIC_API_KEY="lw_sk_your-key-here"

# Use fast Opus for primary tasks, Sonnet for lighter tasks
export CLAUDE_MODEL="claude-opus-4.6-fast"
export CLAUDE_OPUS_MODEL="claude-opus-4.6-fast"
export CLAUDE_SONNET_MODEL="claude-sonnet-4.6"
export CLAUDE_HAIKU_MODEL="claude-haiku-4.5"

# Launch Claude Code
claude

PowerShell / Windows

# Core configuration
$env:ANTHROPIC_BASE_URL = "https://api.lightweight.one/v1"
$env:ANTHROPIC_API_KEY = "lw_sk_your-key-here"

# Use fast Opus for primary tasks, Sonnet for lighter tasks
$env:CLAUDE_MODEL = "claude-opus-4.6-fast"
$env:CLAUDE_OPUS_MODEL = "claude-opus-4.6-fast"
$env:CLAUDE_SONNET_MODEL = "claude-sonnet-4.6"
$env:CLAUDE_HAIKU_MODEL = "claude-haiku-4.5"

# Launch Claude Code
claude

No workaround flags needed. Unlike some third-party proxies, Lightweight’s Anthropic-compatible endpoint works natively with Claude Code. Do not pass --disable-prompt-caching or similar flags — they are unnecessary and may degrade performance.