Claude Haiku 5.5 in Foundry: $0.10 and the 100K cliff
Claude Haiku 5.5 is GA in Microsoft Foundry at $0.10/$0.50 per million tokens, the same Global Standard list price as GPT-6 Luna, and 90% below Haiku 4.5 on paper. The bills diverge on three lines: a tier that charges 5x on every token once a prompt passes 100K, a tokenizer that counts the same text as 30% more tokens, and an EU Data Zone that Luna offers at $0.12/$0.60 while Claude on Foundry has none.
Claude Opus 5.5 in Foundry: the Opus 5 migration cost math
Claude Opus 5.5 is GA in Microsoft Foundry at $4/$20 per million tokens with cache reads at $0.20, which cuts a cache-heavy 60-turn agent session from $8.63 on Opus 5 to $5.10 and brings it within 1.5x of Sonnet 5. The saving can reverse on uncached endpoints that ran Opus 5 with thinking disabled, because thinking is now always on, the default effort dropped to medium, and Foundry still offers no EU data zone, batch pricing or fast mode.
GPT-6 Astra migration on Azure: the GPT-5.6 Sol checklist
GPT-5.6 Sol retires on Foundry in January 2028, so moving to GPT-6 Astra is a choice rather than a deadline, and it touches more than a deployment name: tool calls must move to the Responses API, effort none and temperature disappear, and every line on the price sheet costs 2 to 2.5 times more. A phase-by-phase checklist built on Microsoft's migration process, OpenAI's model guidance and the Learn pages, with the Swedish residency caveat that keeps part of your traffic on Sol.