write-brownfield-guardrail

name	write-brownfield-guardrail
description	Write a Brownfield Guardrail when current code and target direction differ in a way that could mislead the AI — capturing what to use, what not to copy, and when to ask. Use when creating, updating, or applying one (in bootstrap, guidance updates, or brownfield review). A Guardrail records a divergence; it never originates an architecture decision.

Create a Guardrail only when current code and target direction differ in a way that could mislead the AI. Don't create one for aligned situations.

Statuses: Use current (current is approved) · Use target (new work follows target even if code differs) · Target not ready (target exists; don't move there unless scoped) · Ask first (don't decide alone — needs human clarification).

Template:

## Brownfield Guardrail: <Topic>
Status: <Use current | Use target | Target not ready | Ask first>
Source:            <SAD / ADR / spec / decision>
Current state:     <what exists today>
Target direction:  <what new work should use, if known>
Rule for new work:     <what to do for new work>
Rule for existing code:<what to keep or must not change>
Do not copy:       <misleading legacy pattern>
Ask when:          <conditions needing clarification>

A Guardrail is operational guidance, not an architecture decision: if it needs a decision that doesn't exist yet, mark Ask first (with an owner) and recommend formalizing it — never decide it silently.