Version 2.1.36

High-speed output mode for Claude Opus 4.6 that provides faster token generation without switching to a different model. Currently available as a research preview.

# Toggle fast mode from the prompt
/fast

# Or configure in settings.json
{
  "fastMode": true
}

• Uses the same Opus 4.6 model with accelerated output generation
• Billed as extra usage at a premium rate with separate rate limits
• Interactive toggle shows current status: "Fast mode ON" or "Fast mode OFF"
• When enabled, displays with the penguin icon (↯) and orange color theming
• Has its own rate limits; when reached, enters a cooldown period and automatically re-enables when reset
• Model automatically switches to Opus 4.6 if not already selected

Availability:

• Requires a paid subscription
• Requires extra usage billing to be enabled (/extra-usage)
• Requires the native binary (not available via npm install)
• Not available on Bedrock, Vertex, Foundry, or in the Agent SDK
• Organizations can disable fast mode for their accounts

Rate Limiting:

• Displays "Fast limit reached and temporarily disabled · resets in X" when hitting limits
• Shows "Fast limit reset · now using fast mode" when cooldown expires
• Tracks remaining time to reset in the UI

Promotions:

• May show discount percentages for extra usage (e.g., "50% off through [date]")

Fast mode system (search for "Fast mode", "tengu_penguins_enabled", "/fast")

New boolean setting to persist fast mode state across sessions.

{
  "fastMode": true
}

• When true, fast mode is enabled
• When absent or false, fast mode is off
• Can be set via the /fast command or directly in settings.json

Setting schema (search for "When true, fast mode is enabled")

Promotional messages now include fast mode mentions for users who have extra usage enabled:

• "Opus 4.6 is here · $50 free extra usage · Try fast mode or use it when you hit a limit /extra-usage to enable"
• "Opus 4.6 is here · Try fast mode"

Promotional strings (search for "Try fast mode")

The system prompt now includes <fast_mode_info> context explaining fast mode to Claude: > "Fast mode for Claude Code uses the same Claude Opus 4.6 model with faster output. It does NOT switch to a different model. It can be toggled with /fast."

System prompt template (search for "<fast_mode_info>")

The /fast command provides an interactive toggle interface with:

• Current ON/OFF status with visual highlighting
• Tab to toggle, Enter to confirm, Esc to cancel
• Rate limit status and reset countdown when in cooldown
• Link to documentation: https://code.claude.com/docs/en/fast-mode
• Displays pricing information and any active discounts

Toggle UI component (search for "Tab to toggle · Enter to confirm")