routing.cascade_unreachable_tier

What it checks

Crux emits this finding when a non-terminal cascade() tier has no evaluator, making later tiers effectively unreachable.

Why it matters

Cascade tiers are meant to escalate quality, cost, or latency. If an early tier accepts by default, backup tiers may look configured but never run, which makes traces and cost expectations misleading.

How to fix

Add an evaluate callback to non-terminal tiers, or move unconditional tiers to the end.

export const modelCascade = cascade({
  id: 'model-cascade',
  tiers: [
    { model: cheap, evaluate: acceptsCheap },
    { model: strong },
  ],
})

When to suppress

Suppress only when the later tier is intentionally unreachable in the current configuration, for example while staging a rollout.

// crux-lint-disable-next-line routing.cascade_unreachable_tier -- backup tier is staged but not active yet
export const modelCascade = cascade({ id: 'model-cascade', tiers })

Rule metadata

• Rule id: routing.cascade_unreachable_tier
• Category: composition
• Maturity: preview
• Default profiles: recommended, strict
• Default severity: warning