[jonathanprozzi]

Important

@kamescg — review ready. Stacked on #35 (codex/p16g-weak-account-floor); review after #35 and retarget as #35 and #36 land.

To ratify here: the new identity class, class D (provider-local identifiers), for podcast-index, letterboxd and apple-podcasts: byte-exact grammar (no repair), unambiguous typing, valid but never anchor-eligible (P1 floor), category positions as the reference. The reference's ladder already mints these; this makes the spec and registry agree with it.

Coordination: the provider-only apple-podcasts input follows #37's alias-only filter once this branch rebases after #37; this PR and #41 both touch packages/primitives/src/types.ts (whichever lands second takes IdentityClass | null).

Receipt: corpus 209 vectors across 29 schemes; harness 1068 pass / 0 fail; no ledger entry touched.

Child PR of the v1.1.0-alpha umbrella (#15). Part of the parity series: each PR in the series makes a train package behave exactly as the reference implementation's in-tree copy does today, so the published packages can replace those copies without a behaviour change.

Current (train)

The reference implementation's ladder mints three provider-local namespaces, int:podcast-index:<id>, int:letterboxd:film:<slug> and int:apple-podcasts:<id>, through its provider path (byte-exact row grammars, the handle rung), while its own iid package still rejects them as unknown schemes and its spec never defines them. The train refused them outright: the ladder returned unregistered-provider and the registry had no rows, so the published packages could not reproduce identifiers the reference already stores.

Need

The three namespaces legal in the spec and the registry, with the grammar, typing, rung position and eligibility the reference's ladder gives them, and every pre-existing scheme unchanged.

Reconciliation

• @0xintuition/iid-spec: a new identity class, class D, provider-local identifiers (an identifier assigned by one provider, stable within that provider, not governed by any registry outside it); one scheme page per namespace; a dated record under §9.7 (pre-publication amendments); the closed-registry rule is unchanged. Corpus: schemes.json rows and 39 vectors (valid, invalid, canonicalization, eligibility); the fixture validator now pins 29 schemes and gains a regression proving the pin still bites.
• Grammar is byte-exact and canonicalization is the identity function: ^[1-9]\d*$ for podcast-index and apple-podcasts, ^film:[a-z0-9]+(?:-[a-z0-9]+)*$ for letterboxd; zero, leading zeros, uppercase, padding and malformed hyphen runs are invalid and never repaired.
• @0xintuition/iid: registry rows, typing (podcast feed, podcast feed, film) and eligibility: valid and typed but never anchor-eligible, with the new reason provider-local (a P1 floor, the same mechanism as the weak account form in feat(iid, iid-spec): floor weak account handles below anchor eligibility, with the spec amendment and conformance rule (P16g) #35).
• @0xintuition/iid-ladder: the three namespaces resolve instead of returning unregistered-provider; the reference fixtures come out byte for byte on rung handle; category positions follow the reference (podcast-index second after podcastguid for podcast-series and after rssitem for podcast-episode; apple-podcasts matching-only for podcast-series; letterboxd has no movie rung).
• @0xintuition/iid-registry: the typed namespaces classify to podcast-series and movie.
• @0xintuition/primitives: the anchor's class field is typed from the iid union so class D flows through the builder (one type, no behaviour change).

Parity

Matches the reference implementation's ladder for these namespaces (provider-prefixes.ts rows, category rungs, fixtures) and makes the spec and registry agree with what that ladder ships. One path is deliberately left to #37: a provider-only apple-podcasts input for podcast-series still projects to handle through the generic provider fallback, exactly as the reference does on that path; the alias-only filter that keeps it from ever being primary is the ladder-selection PR's, and this branch picks it up when it rebases after #37 lands.

Held out

• No version bump; the release PR freezes versions for the whole family at once.
• The spec could carry a section on reproducible canonicalization and hashing for provider-local values; noted, not written here.

Evidence

• packages/iid-spec: corpus OK, 209 vectors across 29 schemes; 8 validator tests (the 28/30 count regression included).
• packages/iid 345 tests, packages/iid-ladder 168, packages/iid-registry 52, packages/primitives 140, packages/classifications 38; typecheck and lint green in each; root registry:check (14 packages), guard:supply-chain, pack:dry-run pass.
• Conformance harness on top of test(integration): reconcile merged conformance gates and enforce them in CI #36: 1068 pass, 23 todo, 0 fail; no divergence entry touched (the root inventories did not move; the new vectors are consumed by iid's own conformance test).
• Independent review: the conformance pass found every item conforming (reference runtime parity confirmed by source inspection; the sandbox could not execute the reference ladder). The adversarial pass probed the grammar edges per namespace, eligibility through the anchor builder (P1, class D), collateral on the 26 pre-existing schemes, the ladder positions and the vacuity mutations. No findings; the provider-only apple-podcasts path is recorded as the fix(iid-ladder): select identifiers like the reference on normalized evidence, with the alias-only and typed-wd filters pinned by a differential grid (P16h) #37 dependency above.

Review notes

Base codex/p16g-weak-account-floor (#35), which sits on fix/pr15-integration-gates (#36); retarget as those land. Read the class definition and the three scheme pages first, then packages/iid/src/schemes.ts, then packages/iid-ladder/src/provider-prefixes.ts and ladder.ts. The class definition is the newest ruling to ratify.