tempus-mutatur

🔮 Tempus Mutatur

"You wrote this for a model that no longer exists."

Instruction layers are written against a model and then outlive it. The advice that was correct for the family you started on becomes, at best, dead weight — and at worst an active instruction to compensate for a weakness that is gone, which the current family will obey.

legilimens-anthropica answers what does current guidance say. This pass answers the different and more useful question: given what it says, what in these specific files is now wrong? One gathers inputs; this one produces a change list.

What to scan

• The resolved memory files and rule files, plus their git history — when were they written, and against what
• Skill and agent frontmatter, for pinned model identifiers
• Scripts, CI config and settings files, for model IDs and API parameters
• Any dated decision records the repo keeps
• legilimens-anthropica's digest from this session, when it ran

Establish the era from evidence, not assumption. A file's first commit date, a model ID named in it, a decision record's date, or a piece of advice that was current in a known window. Say which evidence you used. If the era cannot be established, this pass is ? — could not verify — the delta between an unknown era and today is not a finding, it is a guess.

Anti-patterns to find

1. Compensation for a fixed weakness. Text instructing the model to do what the current family does unprompted — thoroughness demands, self-verification prose, step-by-step relics, elaborate role-play framing. It was load-bearing once, which is why it reads as harmless now.
2. A dated model identifier that has aged out. A specific model ID in agent frontmatter, a script, a settings file, or CI. IDs are retired on a schedule; an alias is not. Distinguish a pin that is deliberate (reproducibility, a known-good evaluation) from one that is merely old.
3. Advice current guidance reverses. Not "no longer needed" but "now counterproductive" — the most valuable class, and the one nobody finds by re-reading their own file, because it still reads exactly as sensible as the day it was written.
4. Capability the layer does not use because it did not exist. Path-scoped rules, newer hook events, frontmatter fields, plugin mechanisms. The absence is invisible: nothing errors, the layer just does by hand what the harness would now do for it.
5. Era mismatch between files. One file written for the current family, another two generations back, both live and both obeyed. The older one usually wins in novel situations, because it was written when instructions had to be broader.
6. A version fact stated as a constant. A hardcoded cliff, cap, limit or version number that was measured once and typed. It ages silently and is quoted forever — the same defect obliviate-fossilium calls a typed fact.