Claude Sonnet 5.5
Anthropic's production workhorse — speed and capability for everyday coding and agents
Verdict
The one most teams should actually be running in production. Released September 28, 2026, replacing Sonnet 5 at the same $2/$10 per million tokens with a 1M context and 128K output. MCP tool ecosystem is mature. First pick for agentic workflows, code generation, RAG, and day-to-day engineering assistance. Coming from Sonnet 5: disabling thinking and forcing a tool choice both return errors now, and effort levels were recalibrated, so re-run your effort sweep.
Other Text Generation & Reasoning
- GPT-6 AstraProduction
OpenAI's most capable model — 1.05M context, 128K output
- GPT-6.1 SolProduction
The OpenAI default — near-Astra quality at a fifth of the price
- GPT-6 LunaProduction
OpenAI's efficient tier — $0.10/$0.50 with the full 1.05M context
- GPT-5.6Superseded
Previous OpenAI family — Sol/Terra/Luna tiers, superseded by GPT-6
- GPT-5Superseded
OpenAI's 2025 flagship — two families back now
- GPT-5 miniSuperseded
OpenAI's 2025 cost-efficient model — superseded by GPT-6 Luna