# OpenSpec Change: error-spec-conformance

- **Change ID**: error-spec-conformance
- **Package**: `@suaveplan/error`
- **Status**: PROPOSED
- **Date**: 2026-04-26

## Summary

Add `**Verified by:**` lines to every requirement in `openspec/specs/error/spec.md`, fill the three missing test scenarios (subclass narrows code union, stack trace contains subclass name, code values are literal-typed), and rectify the `retroactively ticked` historical hazard so `bun scripts/openspec-conformance.ts @suaveplan/error` exits 0. No public-API changes.

## Current state

`@suaveplan/error` is structurally solid: `SuaveplanError` base class, `defineCodes` registry helper, cycle-safe `walkCauses`, lossless JSON/binary serialization with `markSensitive` redaction, `toSpanEvent` adapter, `setMessageResolver` i18n hook, fast-check property-based round-trip, 100% coverage. The conformance gaps are documentary plus three unwritten test scenarios:

- 9/9 requirements lack `**Verified by:**` lines.
- "Subclass narrows code union" — the spec asserts type-level inference but no test pins it.
- "Stack trace preserved" — the existing `captureStackTrace fallback` test doesn't assert the subclass name appears in `err.stack`.
- "Code values are literal-typed" — type-level scenario with no test.
- `tasks.md` of `2026-04-19-enterprise-error/` carries `retroactively ticked`.

## What changes

1. Add `**Verified by:**` line under every `### Requirement:` block in `openspec/specs/error/spec.md`.
2. Add `src/base/suaveplan-error.spec-conformance.test.ts` covering:
   - "subclass narrows code union" — `expectTypeOf` assertion on `err.code` after `instanceof MySubclass` narrowing.
   - "stack trace contains subclass name" — `expect(err.stack).toContain("MySubclass")` AND `expect(err.stack).not.toMatch(/^\s*Error\b/)`.
3. Add `src/codes/define-codes.spec-conformance.test.ts` covering:
   - "code values are literal-typed" — `expectTypeOf<typeof codes.A>().toEqualTypeOf<"PKG.A">()`.
4. Re-run `bun scripts/openspec-conformance.ts @suaveplan/error` and confirm exit 0.

## Impact

- Public API unchanged.
- Two new test files (~60 lines combined).
- `openspec/specs/error/spec.md` gains 9 `**Verified by:**` lines.