flow.duplicate_step_label

What it checks

Crux emits this finding when one flow body contains the same literal flow.step("label", ...) more than once.

Why it matters

For the Flows beta, a step label is the durable replay identity. Completed step outputs are cached by label so resumed flows can skip work they already finished. Reusing a label makes that cache ambiguous and the runtime rejects the duplicate before it can use the wrong result.

How to fix

Give each durable step a distinct, stable label:

await flow.step("draft-plan", draftPlan);
await flow.step("publish-plan", publishPlan);

Dynamic labels are an advanced escape hatch. Use them only when the generated value is stable across retries and resumes, such as a deterministic branch or loop key from persisted input.

When to suppress

Suppress only when the repeated label is intentional and covered by runtime tests:

// crux-lint-disable-next-line flow.duplicate_step_label -- duplicate path is intentionally unreachable

Rule metadata

• Rule id: flow.duplicate_step_label
• Category: runtime
• Maturity: stable
• Default profiles: recommended, strict
• Default severity: error