Record the migration layer in AGENTS.md

The 2.0 modules section gains the facade layer: the re-export swap of
nameparser.parser/config, the _facade/_config_shim mechanisms
(dirty-tracking, v1-shaped pickle, #280 hook warning), the layering
rule, and the differential-harness pointer. The v1 #256
extension-pattern paragraph is marked historical.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: derek73

AGENTS.md

@@ -111,8 +111,9 @@ Each named attribute (`title`, `first`, etc.) is a `@property` that joins its co
 
 The 2.0 rewrite lands as underscore-private modules alongside the v1 code. These conventions apply to all new-API code and are stricter than the v1 sections above. The full design record (rationale, settled-decision logs, dated amendments) lives in untracked `docs/superpowers/specs/`; this section is the enforceable subset. **A commit that establishes or amends one of these conventions must update this section in the same commit** — grep-driven staleness sweeps miss paraphrased prose (see Workflow above), so write-time maintenance is the mechanism, audits are the backstop.
 
-- **Module layout**: every new module is underscore-private (`_types.py`, `_lexicon.py`, `_policy.py`, `_locale.py`, `_render.py`, `_pipeline/`, `_parser.py`). The public import surface is exactly `nameparser` (and later `nameparser.locales`); `nameparser/__init__.py` holds re-exports and `__all__` only — no logic. Old paths (`nameparser.parser`, `nameparser.config`) stay v1-shaped.
-- **Layering is enforced by `tests/v2/test_layering.py`** (exact-module matching; `if TYPE_CHECKING:` imports don't count): `_types` imports nothing internal at module level — its rendering delegates import `_render` at call time; `_lexicon` and `_policy` sit above `_types` independently (`_lexicon` may import `nameparser.config.*` DATA modules only — vocabulary is single-sourced from the v1 data modules through 2.x, e.g. `config/maiden_markers.py`); `_locale` sits on `_lexicon`+`_policy` (plus `_types` for the shared pickle mixin); `_render` imports `_types` and `_lexicon` (for `Lexicon.default()` and `_normalize`); `_pipeline/*` imports `_types`+`_lexicon`+`_policy` plus in-package `_pipeline` helpers; `_parser` sits on everything except `_render`. Extend the test's `ALLOWED` table when adding a module.
+- **Module layout**: every new module is underscore-private (`_types.py`, `_lexicon.py`, `_policy.py`, `_locale.py`, `_render.py`, `_pipeline/`, `_parser.py`, plus the facade layer: `_facade.py`, `_config_shim.py`). The public import surface is exactly `nameparser` (and later `nameparser.locales`); `nameparser/__init__.py` holds re-exports and `__all__` only — no logic. Since the M11 swap, the old paths are import-path-preserving re-exports: `nameparser.parser` re-exports the `_facade` `HumanName`, `nameparser.config` re-exports the `_config_shim` names (`Constants`, `CONSTANTS`, `SetManager`, `TupleManager`, `RegexTupleManager`); the `config/` DATA modules stay the vocabulary source through 2.x. The whole facade layer is deleted in 3.0.
+- **Facade layer** (`_facade.py`, `_config_shim.py`): the v1-compat `HumanName`/`Constants` over the core. Key mechanisms: `Constants._generation` dirty-tracking (every mutation bumps; facades resolve their `Parser` lazily via `_cached_parser(lexicon, policy)`); `Constants._snapshot()` mirrors `_lexicon._default_lexicon()` (equality-pinned); the facade pickles v1-SHAPED state (component lists, one `__setstate__` path for 1.4 and 2.x blobs; components rebuild via `replace()`, never a re-parse); `_V1_HOOKS` overrides warn once per subclass (#280). The compat contract is the migration spec's promise: warning-free 1.4 code behaves identically except release-log-classified fixes — `tools/differential/` (dev-only, not shipped) verifies this against 1.4-on-PyPI over a 486-name corpus.
+- **Layering is enforced by `tests/v2/test_layering.py`** (exact-module matching; `if TYPE_CHECKING:` imports don't count): `_types` imports nothing internal at module level — its rendering delegates import `_render` at call time; `_lexicon` and `_policy` sit above `_types` independently (`_lexicon` may import `nameparser.config.*` DATA modules only — vocabulary is single-sourced from the v1 data modules through 2.x, e.g. `config/maiden_markers.py`); `_locale` sits on `_lexicon`+`_policy` (plus `_types` for the shared pickle mixin); `_render` imports `_types` and `_lexicon` (for `Lexicon.default()` and `_normalize`); `_pipeline/*` imports `_types`+`_lexicon`+`_policy` plus in-package `_pipeline` helpers; `_parser` sits on everything except `_render`; the facade layer (`_facade`, `_config_shim`, `parser`, `config/__init__`, `__main__`) may import anything public plus `_render`. Extend the test's `ALLOWED` table when adding a module.
 - **Canonical field order** — the seven roles in `Role` enum declaration order, defined once and derived everywhere (properties, `as_dict`, reprs, `comparison_key`). Never restate the order literally.
 - **Method organization**, fixed section order in every class: fields + `__post_init__` validation → alternative constructors → dunders (construction/equality → protocol → operators) → properties → public methods by concern (access → editing → comparison → rendering delegates) → private helpers last, except a helper serving exactly one section may sit at that section's head.
 - **Validation is eager and fail-loud**: every `raise` states the offending value, the expected form, and the fix. Exception taxonomy: wrong type — including wrong element type inside a collection, bare `str` where an iterable of strings is expected, or a `Mapping` where a plain iterable is expected — raises `TypeError`; well-typed but unacceptable values raise `ValueError`; failed enum lookups stay `ValueError` for any input (stdlib `EnumType` precedent).
@@ -135,7 +136,7 @@ The 2.0 rewrite lands as underscore-private modules alongside the v1 code. These
 
 Add a dedicated `copy.deepcopy()` round-trip test for it too (see `test_regexes_deepcopy_roundtrip`/`test_nickname_delimiters_deepcopy_roundtrip` in `tests/test_constants.py`), not just reliance on conftest's autouse snapshot/restore exercising it incidentally. `TupleManager`/`RegexTupleManager.__getattr__` answer *any* unknown attribute lookup — dunder probes like `__deepcopy__` raise `AttributeError` (never answered as config keys), everything else still returns `self.get(attr)`/`EMPTY_REGEX` — so a new manager subtype or a `__getattr__` tweak can silently break `copy.deepcopy` (this bit `RegexTupleManager` before the dunder-lookup guard was added). A direct test on the new attribute's own manager instance catches that where the conftest fixture, which never asserts on the copy, would not. As with the scalar-attribute pattern above, also check `AGENTS.md` itself for now-stale references when you touch this.
 
-**Unknown-key attribute access on `TupleManager`/`RegexTupleManager` warns (1.4, #256)** — a key not currently in the dict emits `DeprecationWarning` naming the miss and the known keys (`_warn_unknown_key`), before falling back to the same `None`/`EMPTY_REGEX` default as before; `.get()` stays silent. Dunder probes (`__deepcopy__`) still raise `AttributeError` outright, and single-underscore probes (`_repr_html_`, IPython's `_ipython_canary_method_should_not_exist_`, etc.) are excluded from the warning too — no real config key starts with `_`, so both guards just keep protocol/introspection probes from misfiring as "typo" warnings. This means internal parser code that reads `self.C.regexes.<key>` unconditionally (e.g. `squash_bidi`'s `bidi`) now warns if a caller's custom `regexes` dict omits that key — a previously-silent partial-override pattern is on the same deprecation path as an actual typo.
+**Unknown-key attribute access on `TupleManager`/`RegexTupleManager` warns (1.4, #256) — 2.0 note: the warning became a hard `AttributeError` naming the known keys (shim `TupleManager`); the paragraph below describes the deleted v1 machinery and applies only when reading v1 history.** — a key not currently in the dict emits `DeprecationWarning` naming the miss and the known keys (`_warn_unknown_key`), before falling back to the same `None`/`EMPTY_REGEX` default as before; `.get()` stays silent. Dunder probes (`__deepcopy__`) still raise `AttributeError` outright, and single-underscore probes (`_repr_html_`, IPython's `_ipython_canary_method_should_not_exist_`, etc.) are excluded from the warning too — no real config key starts with `_`, so both guards just keep protocol/introspection probes from misfiring as "typo" warnings. This means internal parser code that reads `self.C.regexes.<key>` unconditionally (e.g. `squash_bidi`'s `bidi`) now warns if a caller's custom `regexes` dict omits that key — a previously-silent partial-override pattern is on the same deprecation path as an actual typo.
 
 **Adding a word to a config set** — first check the *other* sets for the same word (grep `nameparser/config/` or intersect the sets in a `python3 -c`). Real overlaps exist: `do`/`st`/`mc` ∈ `PREFIXES` ∩ `TITLES`/`SUFFIX_ACRONYMS`; `abd` = "ABD" ∈ `SUFFIX_ACRONYMS`; `abu` ∈ `PREFIXES` ∩ `bound_first_names` (position-dependent: leading token → first-name join, mid-name → last-name join). Usually position-dependent and harmless, but can force a guard or an exclusion (the `last_base` all-particles guard; dropping `abd` from `bound_first_names`).