Anthropic releases Claude Sonnet 5.5 and GitHub starts Copilot rollout
The model keeps Sonnet's published $2/$10 token rates, adds a 1M context window and changes thinking, tool and computer-use behaviour that can affect existing agents.
By Aaron Felix · Updated 7 October 2026
What this changes for UK buyers
Teams gain a lower-rate alternative to Opus 5.5 across major cloud and coding routes, but a silent model swap can break orchestration or hide expected tool-call text.
What buyers should do
Pin the model in a test environment and compare accepted work, tool failures, logs, cache use, latency, safeguards, review and complete cost before migration.
Primary announcement
Anthropic Claude Sonnet 5.5 launch ↗This is a dated source-linked buyer briefing. A vendor announcement does not prove UK account eligibility, an independent performance result or regulatory compliance. Open the primary source and confirm the exact plan before changing a production workflow.
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