wit-breaking-change-check

name	wit-breaking-change-check
description	Classify WIT interface changes as breaking or non-breaking against frozen version markers. Use this skill when the user wants to check WIT breaking changes, review a WIT diff, verify whether a WIT change is breaking, or run a WIT compat check. Trigger on: 'check WIT breaking changes', 'review WIT diff', 'is this WIT change breaking', 'WIT compat check'.

WIT Breaking Change Check

Classifies every modification in the current WIT diff against the breaking-change taxonomy and reports a verdict for each finding.

When to Use

• Before merging any branch that touches wit/
• When reviewing a PR that modifies WIT interface definitions
• To verify a WIT change is safe before publishing a plugin-compatible release

Procedure

1. Run git diff origin/master -- wit/ to obtain the current diff.
2. For each wit/vN/ directory in the diff, check whether wit/vN/.frozen exists. If absent, report the version as experimental and state that components must be rebuilt against the WIT shipped by the target host; do not claim the frozen-version compatibility window applies.
3. For each frozen version with changes, classify every modification against the breaking-change taxonomy in wit/VERSIONING.md:
   • Breaking: removing/renaming any type, function, record field, enum case, or variant case; adding a case to an existing enum or variant; changing a function signature; changing a field type; reordering record fields; adding a required (non-optional) field to an existing record; adding a non-capability-gated required function to an existing interface.
   • Non-breaking: new flags bits, new capability-gated functions, new record/variant/enum types (but not cases added to an existing enum or variant), new interfaces, new worlds, @since/ annotation additions.