Anthropic has introduced a new fast mode feature for its Claude Code platform, designed to accelerate response times. This new mode prioritizes speed over cost efficiency, offering quicker results for interactive tasks like debugging and code iteration. Users can enable it via the `/fast` command within the Claude Code CLI and VS Code extension.

Fast mode leverages the existing Opus 4.6 model but utilizes a different API configuration to achieve faster outputs. It's particularly useful for time-sensitive projects. While offering quicker responses, users should be aware of the increased per-token costs. The feature is currently in research preview, and its availability and pricing may change based on user feedback.

Fast mode has separate rate limits from the standard Opus 4.6. If the fast mode rate limit is reached, the system automatically falls back to standard speed. Fast mode is not available on third-party cloud providers but is accessible through the Anthropic Console API and Claude subscription plans.

Fact: Anthropic's Claude 2.1 model, released in late 2023, offered a 200,000 token context window, a significant improvement over previous versions. This expansion allows for processing more complex, lengthy codebases within a single prompt.