Developer and publisher of Claude Sonnet 5.5; released it as the mid-tier workhorse companion to Claude Opus 5.5, positioning it around cost-per-task efficiency rather than headline capability.
Integrated Sonnet 5.5 into GitHub Copilot at general availability across IDEs and plans, extending Anthropic's reach into the developer-tools market.
Early enterprise tester; reported Sonnet 5.5 processed support tickets 20% faster with fewer wrong decisions than production Claude models, used as a customer proof point for the efficiency claim.
BO
Box, Slack, Lovable, Base44, Atlassian
Named enterprise customers cited with concrete efficiency gains - e.g. Box 2.4x faster with 12% fewer tokens, Slack 14% fewer output tokens, Lovable a third fewer tool calls, Atlassian 30% faster agent operations - substantiating Anthropic's cost/speed claims.
AW
AWS, Google Cloud, Microsoft Azure
Cloud hyperscaler distribution partners hosting Sonnet 5.5 at launch, extending Anthropic's enterprise procurement channels beyond its own API.
OP
OpenAI and Google (Gemini)
Rival frontier-model developers whose models are the direct competitive benchmark against which analysts are pricing and scoring Sonnet 5.5, including a published comparison against Gemini 3.1 Pro.