News
Claude Opus 5.5 Released: ~40% Cheaper, Faster Agentic Coding
Anthropic launched Opus 5.5 on September 22, the first model in the Claude 5.5 series: near-flagship performance on most tasks at ~40% lower running cost, aimed at agentic coding and knowledge work. Plugins and a Marketplace launched alongside.
On September 22, Anthropic officially launched Claude Opus 5.5, the first model in the Claude 5.5 series.
Upgrade Highlights
- Near-flagship performance: officially close to the previous flagship across most workloads.
- ~40% cost reduction: running costs about 40% lower than Opus 5 — the most tangible part of this upgrade.
- Agentic coding and knowledge work: strengthened agent-style coding and long-form knowledge work.
The Ecosystem Expands in Parallel
Alongside the new model, Anthropic shipped an ecosystem update:
- Build plugins for Claude: support for building plugins for Claude;
- Claude Marketplace: discover and get plugins, agents, and services;
- Personal connectors: easy ways to plug in your own tools.
Sonnet 5.5: The Mid-Tier Value Pick
On September 29, Anthropic also released Claude Sonnet 5.5, aimed at mid-tier speed and value. The two new models divide labor clearly.
Which to Pick
- Heavy coding / agent workflows: Opus 5.5 — strong capability, 40% cheaper than its predecessor.
- High-frequency daily use at volume: Sonnet 5.5 — friendlier speed and pricing.
- Already on Opus 5: worth evaluating a migration — a 40% cost cut matters a lot for teams running agents long-term.
Bottom line: Anthropic didn’t pile on parameters this time — it pushed “same capability, lower cost” to the extreme. For developers, that’s good news.