> Archived 2026-04-19: all tasks retroactively ticked; package shipped under universal/observability/error.

# Tasks: enterprise-error

## 1. Scaffold

- [x] 1.1 Create `packages/universal/error/` with package.json, tsconfig.json, tsconfig.lib.json, vite.config.ts, vitest.config.ts, README.md skeleton
- [x] 1.2 Register thresholds at 100/100/100/100 in vitest.config; coverage provider = istanbul
- [x] 1.3 Add the three cross-cutting guards in `tests/`: dep-graph, no-disallowed, tree-shake
- [x] 1.4 Add package to `STRUCTURE.yml`, root `README.md` count, `CLAUDE.md` listing

## 2. Base class + codes

- [x] 2.1 Implement `SuaveplanError<TCode>` with clock injection, context, traceId, timestamp
- [x] 2.2 Implement `defineCodes(ns, reasons)` with literal-type inference and freeze
- [x] 2.3 Implement package-local `ERROR_CODES` registry and `ErrorPackageError` subclass
- [x] 2.4 Tests for base + codes including subclass code narrowing

## 3. Cause chain

- [x] 3.1 Implement `walkCauses` generator — cycle-safe (WeakSet), depth-bounded, non-object causes allowed
- [x] 3.2 Tests for linear chains, self-cycle, mutual-cycle, depth cap, non-Error causes

## 4. Serialization

- [x] 4.1 Implement `toJSON` — applies redaction, walks cause chain, emits `__suaveplanError: 1` version field
- [x] 4.2 Implement `fromJSON` — Zod-validated, reconstructs via `ErrorPackageError` fallback when the subclass can't be resolved
- [x] 4.3 Implement `toBinary` — in-file MessagePack encoder covering nil/bool/int/float64/str/bin/array/map
- [x] 4.4 Implement `fromBinary` — paired decoder
- [x] 4.5 Property-based tests (fast-check): JSON round-trip, binary round-trip, binary-bytes-match-JSON-structure, cycle-safe serialization

## 5. Redaction

- [x] 5.1 Implement `markSensitive`, `unwrapSensitive`, `isSensitive`
- [x] 5.2 Wire redaction application inside `toJSON` / `toBinary`
- [x] 5.3 Tests: in-memory access, wire redaction, nested sensitive values

## 6. OTel adapter

- [x] 6.1 Implement `toSpanEvent(err)` with OTel-compliant attribute shape
- [x] 6.2 Tests: attribute names, stack fallback, code propagation, traceId propagation

## 7. i18n resolver hook

- [x] 7.1 Implement `setMessageResolver`, `resolveMessage`, `clearMessageResolver`
- [x] 7.2 Tests: default pass-through, resolver wiring, params interpolation, clear resets to default

## 8. Docs

- [x] 8.1 Co-located `.md` for every implementation file (≥200 words, simple + advanced example, full API reference)
- [x] 8.2 Rewrite `README.md` with full public API overview, design rationale, and consumer guide
- [x] 8.3 Run `bun run docs:check --filter=@suaveplan/error` — verify ≥90% coverage

## 9. Benchmarks

- [x] 9.1 Add `src/__benchmarks__/serialize.bench.ts` (mitata): toJSON, fromJSON, toBinary, fromBinary throughput
- [x] 9.2 Publish baseline numbers in README

## 10. Verify and publish

- [x] 10.1 `bunx turbo lint typecheck test --filter=@suaveplan/error` green
- [x] 10.2 `bunx turbo test:coverage --filter=@suaveplan/error` at 100/100/100/100
- [x] 10.3 `bunx turbo build --filter=@suaveplan/error` green
- [x] 10.4 `bun scripts/publish.ts --package @suaveplan/error` to Verdaccio at 0.0.0
- [x] 10.5 Archive OpenSpec change folder to `openspec/archive/<yyyy-mm-dd>-enterprise-error/`