Model
claude-sonnet-4.5
Claude Sonnet 4.5, released in September 2025 at unchanged Sonnet pricing, was described by Anthropic as its strongest coding model at the time and the one best suited to long-running agents — the company said it could stay focused on a multi-step task for more than 30 hours and reported 77.2% on SWE-bench Verified. It shipped under Anthropic's ASL-3 safeguards, with the company calling it its "most aligned frontier model yet" on the basis of its own evaluations.
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- Safety & alignment 3
- Models & capabilities 3
- Money & business 2
- Compute & infrastructure 1
Anthropic researchers find a verbalizable 'global workspace' in language models
A new probing method found a small, layer-localised set of representations that models draw on when reporting their own reasoning, resembling neuroscience's global workspace theory of consciousness.
Safety & alignment
Anthropic releases Claude Sonnet 4.6
Early testers preferred it to Sonnet 4.5 on coding tasks about 70% of the time, and to the larger Opus 4.5 about 59% of the time, at unchanged Sonnet pricing.
Models & capabilities
Anthropic releases Claude Opus 4.5
Priced at $5/$25 per million input/output tokens, roughly a third of Opus 4.1's rate, and Anthropic said it beat Sonnet 4.5's best score using 76% fewer output tokens.
Models & capabilities · Money & business
Microsoft and Nvidia to invest up to $15bn combined in Anthropic; Anthropic commits $30bn to Azure
The deal added Azure as a third cloud for Claude alongside AWS and Google Cloud, with Anthropic committing to buy up to a gigawatt of Nvidia Grace Blackwell and Vera Rubin compute.
Compute & infrastructure · Money & business
Anthropic open-sources its political even-handedness evaluation
Anthropic's own grading method scored Claude Sonnet 4.5 at 94% even-handedness, behind Gemini 2.5 Pro and Grok 4 but ahead of GPT-5 and Llama 4.
Safety & alignment
Anthropic open-sources Petri, an automated model auditing tool
Testing 14 frontier models on 111 scenarios for deception and power-seeking, Anthropic's tool rated Claude Sonnet 4.5 the lowest-risk model, narrowly ahead of GPT-5.
Safety & alignment
Anthropic ships Claude Sonnet 4.5
Anthropic reported 77.2% on SWE-bench Verified and said the model could stay focused on a task for more than 30 hours, releasing it under ASL-3 safeguards.
Models & capabilities