Reliability TypeScript active any

Async boundary validation rejects invalid input before side effects

rel-typescript-001

Intent

Prevent malformed external data from causing writes or side effects before validation completes.

Applicability

Applies to TypeScript boundary handlers that parse external input and may run async schema logic.

What to inspect

Schema parsing APIs, async refinements, and whether side effects begin before parsing completes.

Pass criteria

Boundary input is fully parsed, using async parse APIs when needed, before side effects begin.

Fail criteria

The diff starts side effects before finishing validation or uses synchronous parse APIs on async schema logic.

Do not flag

Fully synchronous schemas with no side effects before parse completion.

Confidence guidance

HIGH when the wrong parse API or ordering is directly visible. MEDIUM when async schema behavior is partly hidden. LOW when boundary ownership is unclear.

Remediation

Complete runtime parsing first and use async parse APIs for schemas with async logic.

Pass example

const input = await Schema.parseAsync(req.body)

Fail example

const input = Schema.parse(req.body)
await save(input)