GPT-6 Astra in Foundry: the price, the gate and the EU gap
GPT-6 Astra arrived in Microsoft Foundry on 3 September 2026 at $10/$50 per million tokens, the same list price as Claude Fable 5.1 and 2.5x GPT-5.6 Sol on promo, behind a Limited Access gate and with no EU Data Zone. The cost math on document jobs and 60-turn agent loops, the 272K long-context cliff, what the Critical cyber rating means for refusals, and how a Swedish team should handle residency until the EU zone lands at its new 20% premium.
Claude Fable 5.1 in Foundry: cache math and the EU caveats
Claude Fable 5.1 keeps Fable 5's $10/$50 pricing but cuts cache reads to $0.25 per million tokens, which turns a 60-turn agent session from $17.25 into $10.50 and shrinks the premium over Opus 5 from 2x to about 22%. On Microsoft Foundry it ships Anthropic-hosted only, with no EU data zone, no Batches API, a zero default quota on pay-as-you-go, mandatory 30-day retention until Enterprise Frontier Safeguards arrive, and three breaking changes for teams migrating from Fable 5.
AI Agent Cost Economics: Why 100x and How to Cut It
Agent loops cost 10x to 50x what a chatbot interaction costs; multi-agent systems add another order of magnitude. The cost compounding is structural, not a bug. The cost reduction is structural too. Decomposing where the tokens go and how to bring agent economics back from runaway to acceptable.
Prompt Caching: Cutting LLM Costs Without Quality Loss
A technical guide to prompt caching across Claude, Azure OpenAI, and GPT — what belongs in the cache, how to structure cache breakpoints, TTL realities, hit-rate optimization, and the anti-patterns that erase the savings.