# Capability Spec Delta: mime (spec-conformance)

**Package**: `@suaveplan/mime`
**Status**: PROPOSED

This delta annotates each existing requirement in `openspec/specs/mime/spec.md` with a `**Verified by:**` line and rectifies two pieces of implementation drift (MIME-07 and MIME-12 / MIME-16 schema invocation). No requirement semantics change.

## MODIFIED Requirements

(See `openspec/specs/mime/spec.md` for the full requirement bodies.)

| Requirement | Verified by |
|---|---|
| MIME-01 Magic-byte detection via compiled trie | `src/detection/detection.magic.test.ts` |
| MIME-02 All-matches magic-byte detection | `src/detection/detection.magic.test.ts` |
| MIME-03 RFC 7231 Content-Type parsing | `src/content-type/content-type.test.ts` |
| MIME-04 Content-Type round-trip serialisation | `src/content-type/content-type.test.ts` (incl. property-based) |
| MIME-05 Content-Type equality and matching | `src/content-type/content-type.test.ts` |
| MIME-06 Curated IANA-sourced registry | `src/db/db.test.ts` |
| MIME-07 Runtime registry extension | `src/db/db.test.ts` AND `src/db/db.spec-conformance.test.ts` |
| MIME-08 Reverse lookups | `src/reverse/reverse.test.ts` |
| MIME-09 BOM charset sniffing | `src/charset/charset.test.ts` |
| MIME-10 HTML meta charset sniffing | `src/charset/charset.test.ts` |
| MIME-11 XML declaration charset sniffing | `src/charset/charset.test.ts` |
| MIME-12 Unified detect() | `src/detection/detection.extension-contenttype.test.ts` AND `src/db/db.spec-conformance.test.ts` |
| MIME-13 detectFromStream() interim shim | `src/detection/stream.test.ts` |
| MIME-14 Signature registry extension | `src/detection/from-magic-bytes/registry.test.ts` AND signature-pack tests |
| MIME-15 Structured errors | `src/error-codes.test.ts` AND `src/errors/errors.test.ts` |
| MIME-16 Zod schemas | `src/schemas/mime.schemas.test.ts` AND `src/db/db.spec-conformance.test.ts` |
| MIME-17 OTel instrumentation | `src/telemetry/meters.test.ts` |
| MIME-18 Legacy shim | `src/legacy/legacy.test.ts` |
| MIME-19 Property-based tests | `src/content-type/content-type.test.ts` (round-trip property) AND `src/detection/detection.magic.test.ts::"always returns MagicBytesResult or undefined — never throws"` AND `src/db/db.test.ts::"every registered entry is retrievable by mime"` |
| MIME-20 Benchmarks | `src/db/db.spec-conformance.test.ts::"src/__benchmarks__/ exists with the documented bench suites"` |
| MIME-21 sideEffects: false + 100% coverage | `tests/tree-shake.test.ts` AND `tests/no-disallowed.test.ts` AND coverage gate |

## Newly added tests in this change

- `src/db/db.spec-conformance.test.ts` — pins `registerMimeEntry` ParseError on invalid shape (MIME-07), `detect` ParseError on invalid input field types (MIME-12 / MIME-16), and `__benchmarks__/mime.bench.ts` existence (MIME-20).

## Drift fixed inline

- `src/db/registry.ts::registerMimeEntry` now invokes `MimeEntrySchema.safeParse` and throws `ParseError` on failure.
- `src/detection/detect.ts::detect` now invokes `DetectInputSchema.safeParse` and throws `ParseError` on field-type mismatches; the at-least-one-source refinement is treated as non-fatal so the documented `detect({})` → `application/octet-stream` default is preserved.
- `SignatureSchema`, `MagicBytesResultSchema`, `ExtensionDetectionResultSchema`, `ContentTypeDetectionResultSchema`, `StreamDetectionResultSchema`, and `DetectResultSchema` carry `// schema: boundary-only` markers — they describe cross-process serialisation shapes, not runtime arguments.