Changelog

We're excited to announce the release of Claude Haiku 4.5, Anthropic's latest lightweight coding model. Haiku 4.5 delivers near-frontier coding quality with low latency and consistent tool reliability. We're giving up to 20 free user messages over the next two weeks to everyone subscribed to a monthly paid plan once the pricing migration is complete — no action required.

We recently announced a new credit-based pricing model, replacing monthly user message limits with flexible credit pools across all Augment activities. That same change also lets us deliver new models faster, without waiting for backend migrations, starting with Haiku 4.5.

Performance that punches above its weight

Haiku 4.5 advances small-model performance significantly. In Augment’s evaluation of real-world coding tasks, Haiku 4.5 achieves approximately 90% of Sonnet 4.5’s performance, while running significantly faster. It handles simpler coding tasks with ease. For complex, multi-file work, we find that Sonnet & GPT-5 remain the stronger choice.

In our internal tests, Haiku 4.5 came close to Sonnet 4.5 in terms of quality, yet at a much higher speed:

• Head-to-head preference: In testing across identical prompts, internal testers preferred responses from Sonnet 4.5 (51.4%) over Haiku 4.5 (46.5%).
• Speed advantage: Haiku 4.5 achieved faster time-to-success in 85% of evaluations, completing tasks 34% faster on average.

Try Haiku 4.5 early — up to 20 User Messages on us

We’re excited to bring Haiku 4.5 to Augment users. All monthly paid users can now try it with up to 20 free User Messages for the next two weeks, based on your usage. Pricing migration is still underway, but you can start using Haiku now, and we think you’ll love it.

What you’ll receive:

• Up to 20 Haiku User Messages’ worth of credits (valued at 1,000 credits per User Message) for the next two weeks
• Automatic credit application once pricing migration completes. No action required
• This promotion is available to all users who are on a monthly paid plan as of October 15, 2025.

The fine print:

• Your credit will be applied to your balance after the pricing migration from October 20th to October 31st is complete.
• During this transition period, you won’t have visibility into your Haiku vs. Sonnet usage (this feature will become available after your account migration).
• You will receive an email in early November after the pricing migration is complete. This will include the number of Haiku 4.5 user messages you've used and the number of credits you’ve received from this promotion.

For example, if you send 48 Haiku User Messages over the next two weeks, you’ll receive the full 20 User Messages’ worth of credits after our pricing migration.