model-adaptation

model-adaptation

The toolkit's home for what changes about your prompts, skills, and scaffolding when the underlying model changes — currently the Claude 5 family (Fable 5 + Mythos 5) succeeding Opus 4.x, plus the cross-vendor DeepSeek landscape (V4 flash/pro). It advises and audits; it does not build. skill-writer/skill-review enforce the authoring half, loop-controller the long-run half, and orchestrator the multi-agent half — this skill is where the why and the migration checklist live so those enforcement points stay in sync.

Why this skill exists

Model-adaptation guidance is the kind that rots. It's true only relative to a model generation, it cuts across every skill, and it has no natural owner — so it survives as scattered asides ("Fable 5 reroutes flagged agents", a stray /effort note) that drift out of date the moment a new model ships and nobody remembers to reconcile them. This skill is the single owner. When a new model lands, you update one landscape table here and re-run the migration audit, instead of hunting the toolkit for stale assumptions. Everything model-specific is quarantined in the Current landscape section below; the patterns are written to outlive it.

Source of record: Anthropic's Prompting Claude Fable 5 and Prompting best practices; for DeepSeek runs, the DeepSeek API docs and Thinking Mode. Re-fetch these when a new model generation ships — that's the trigger to update this skill.

The core move: a capability jump means PRUNE, not ADD

The reflex when a stronger model arrives is to write more guidance to exploit it. That reflex is usually wrong. A skill written for a weaker model is a cast made around that model's failure modes — enumerated do's and don'ts, rigid templates, anti-laziness nagging, "show your work" instructions. A stronger model has fewer of those failure modes, so the cast now constrains rather than supports it, and Anthropic measures this as a real degradation in output quality, not a wash.