Dependency Upgrade Validation

The upgrade is the easy part; proving the project still coheres is the work. This skill takes over after versions are chosen -- typically bun update -i -r or an equivalent interactive pick -- and validates what landed: the real delta from git, peer and engine integrity, breaking changes and migrations across every version crossed, features worth adopting, and verification gates that run the project rather than reading about it. It also answers the inverse question: can a held-back package move, and why is it in package.json at all.

When to Use

• Validating a batch upgrade -- "I upgraded a lot of packages, validate everything"
• Assessing a held-back package -- "can we upgrade X?", "what blocks it?"
• Questioning a dependency -- "why do we even have X, we don't use it"
• Reading release notes -- breaking changes, migration steps, new features across the versions crossed
• Post-upgrade triage -- type, build or test failures that appeared after an update
• Pre-upgrade recon -- what a bump would cost before anyone runs it

Critical Rules