Structured-Output-Picker — 在解码处约束，还是在校验处约束？

One-liner: Three local libraries (Outlines, Instructor, Guidance) plus provider-native structured outputs all "make the model emit valid structure", but they enforce at different points and fail differently. Pick by how costly a malformed output is and whether you control the decoder. Then pick the failure stance — Assert (hard-fail + retry) vs Suggest (soft nudge, degrade gracefully) — borrowed from DSPy's constraint primitives.

This is an ENHANCE overlay. The four enforcement mechanisms each have a working local skill; what no single one provides is the cross-library *which-one

• how-to-handle-failure* decision. That gap is hit every time an LM output is consumed by code. For what shape the content should take (code vs JSON vs prose), descend first to [[agentsop-output-format-by-model]] — this skill assumes the shape is already chosen and asks only how to enforce it.

1. 何时激活 (When to activate)