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description: "Deep audit of the ESM/ESP plugin parser — GRUP walk, sub-record byte accounting, per-record schemas, FormID remap, CELL/WRLD walkers, ESM→ECS handoff" argument-hint: "--focus <dimensions> --game <name> --depth shallow|deep"

ESM / Plugin Parser Audit

Audit crates/plugin/ (~73k LOC in src/) as a parser: GRUP walker, sub-record byte accounting, per-record schema dispatch, FormID load-order remap, CELL/WRLD walkers, and the EsmIndex → ECS handoff. Per-game audits (/audit-fnv, /audit-skyrim, …) each sample one game's slice; this skill owns the parser itself.

Architecture: Orchestrator. Each dimension runs as a Task agent (max 3 concurrent).

Read .claude/commands/_audit-common.md and .claude/commands/_audit-severity.md for shared protocol (dedup, methodology, finding format). Do not duplicate them here.

Scope

Crate: crates/plugin/src/ — esm/reader.rs (EsmReader, EsmVariant, GameKind, FormIdRemap, GlobalSlot, zlib decompression), esm/sub_reader.rs (SubReader), esm/records/ (parse.rs = the top-level GRUP walker parse_esm[_with_load_order]; mod.rs is a re-export barrel; index.rs EsmIndex; eight dispatch_*.rs routers; grup_walker.rs; per-type decoders incl. actor/, items.rs, items/consumable.rs, container.rs, condition.rs, weather.rs, weather_settings.rs (Starfield WTHS), load_screen.rs, pkin.rs, misc/*.rs incl. story_manager.rs, location.rs (LCTN), relationship.rs (RELA)), esm/cell/ (walkers.rs, support.rs, wrld.rs, helpers.rs, mod.rs data types), esm/strings_table.rs, equip.rs, and the Redux-native tier (datastore/manifest/record/resolver).

Not in scope: cell-loader consumption of CellData (/audit-<game> Dim 1); VMAD translation (/audit-scripting); NIF (/audit-nif); BSA/BA2/CSG incl. the FO4 previs header → cell-grid recovery (/audit-parsers); src/extension.rs + crates/sdk extension manifests (/audit-tooling); WTHR/CLMT/WATR/LTEX/GRAS translation and HNAM sun consumption (/audit-exterior — byte-level decode of those records stays here); consumption semantics of src/consumables.rs / expand_leveled_loot (equip.rs) — timed restoratives, container loot, LSCR selection (/audit-gameplay; the decode contract stays here, Dim 4); CHARAL formulas (/audit-character).

Ground truth: docs/engine/plugin-loading.md, docs/engine/esm-records.md, docs/engine/pipeline-overview.md. Every non-obvious decode should cite a wbDefinitions{TES4,FNV,TES5,FO4,FO76,SF1}.pas:line range (crate docstring in crates/plugin/src/lib.rs); a decode with no citation and no test is a guess (feedback_no_guessing) — flag it.

Parameters (from $ARGUMENTS)

• --focus <dimensions>: comma-separated dimension numbers. Default: all 8.
• --game <name>: restrict Dim 8 real-data validation to one game. Default: every game with on-disk data (_audit-common.md § Game Data).
• --depth shallow|deep: shallow = schema/contract check; deep = byte-level trace against real masters. Default deep.

Extra Per-Finding Fields

• Dimension: Header & GRUP Walk | Sub-Record Byte Accounting | FormID & Load Order | Record Schema Dispatch | CELL / WRLD Walkers | Localized Strings | ESM→ECS Handoff | Real-Data Validation
• Record / Sub-record: 4-char code(s) (e.g. NPC_ / ACBS), or —.

Phase 1: Setup

1. Parse $ARGUMENTS. mkdir -p /tmp/audit/esm.
2. gh issue list --repo matiaszanolli/ByroRedux --limit 200 --json number,title,state,labels > /tmp/audit/esm/issues.json.
3. Read the latest docs/audits/AUDIT_ESM_*.md plus the ESM dimensions of the latest AUDIT_{FNV,SKYRIM,FO4,STARFIELD}_* reports — this crate's findings historically live there, so that is where your duplicates are.
4. cargo test -p byroredux-plugin; record the pass count (a pre-existing failure is context, not a finding). Never run --ignored / --include-ignored on this crate — the real-data tests parse whole masters (Starfield ≈ 4 GB parsed) and have OOM-killed sessions past 20 GB; use Dim 8's single-file probes instead.

Suggested emphasis: the 2026-08 → 09-11 reports yielded mostly Localized Strings, ESM→ECS Handoff, CELL/WRLD and FormID remap; the 2026-09-21 report's MEDIUMs were Byte Accounting (Oblivion LVLO/LVLD, FO4 TERM, LTEX.GNAM) and Header/GRUP (inflation ceiling, skip-arm clamp), all found by Dim 8's real-data census — run it, don't skip it. The 2026-09-29 report's MEDIUM/LOWs were again Byte Accounting + FormID: non-FormID u32s fed to the remap (FO4 TRDA FFFF sentinel, Oblivion EFID char4 codes), fixed in 9b099b31f (#5075/#5076) — see Dim 3 shape (4). The 2026-10-08/10-09 MEDIUMs were decodes that contradict their own wbDefinitions*.pas entry (SM SNAM/RNAM, REGN WNAM, PKIN VNAM, SCOL/PKIN FLTR, PKDD Dialogue Type offset — all since fixed, #5493 136048a95 / #5492 dae08000d) — open the xEdit definition for every decoder touched since the last report rather than trusting its doc comment.

Phase 2: Dimensions

Dimension 1: Header Detection & GRUP Walk (highest blast radius)

Paths: crates/plugin/src/esm/reader.rs, esm/records/{parse,grup_walker}.rs First step: grep -rn 'group_content_end(' crates/plugin/src | grep -v 'tests/\|///' Why first: a header-size or GRUP-bounds error desyncs the whole file; everything downstream decodes structurally valid garbage. Guards (run, confirm live — not #[ignore]d, not vacuous): reader::tests::game_kind_from_header_maps_real_master_hedr_values, grup_walker::tests::every_recursive_grup_walker_honours_the_shared_depth_cap (table of walkers nested past MAX_GRUP_NESTING_DEPTH; a walker missing from the table is invisible to it), reader::tests::bounded_group_content_end_clamps_to_parent_end, and the compressed_record_* / inflation_ceiling_clears_every_observed_vanilla_shape tests. Checklist (what the guards cannot see):

• EsmVariant::detect (data[20..24] == b"HEDR" ⇒ 20-byte Oblivion headers) has its length guard before the slice; no caller hardcodes a variant outside tests / with_variant.
• GameKind::from_header(variant, hedr_version, record_version) uses banded float compares plus the TES4 record version as a second key (Skyrim LE and FO3 GOTY both stamp HEDR 0.94 → record version 40 vs 2; FO4 DLC 0.95 → 131). Vanilla HEDR: FO3 0.94, FO4 1.0, Starfield 0.96, FNV 1.34, Skyrim SE 1.71, FO76 — a live-service value that drifts with patches (68.0 → 266.0 → 279.0 as of 2026-09-20; floor 60.0). A mis-band is not latent: FO4-only arms in items.rs (ARMO DATA swaps value/weight/health order at the same 12-byte length, WEAP DATA empty, BOOK 8-byte) would silently swap armor stats and zero every weapon. Any new per-game schema split widens this blast radius — check.
• Missing/short HEDR falls back to GameKind::Fallout3NV (Default): confirm each call site is deliberate and no branch treats "defaulted" as "detected FO3".
• Universal GRUP bound (#3503/#3721/#4076/#4644): every self-recursive walker takes bounded_group_content_end(header, depth, parent_end, name) and threads depth + 1 into its _inner; skip arms too seek to the parent-clamped end via seek_to (the depth-cap arm inside bounded_group_content_end included). The raw group_content_end may appear only in the non-recursive top-level loop (records/parse.rs, the only skip_group caller), cell/wrld.rs::parse_wrld_group and grup_walker.rs::walk_info_records' nested-group skip (both .min(end) themselves). Regression = a new recursive walker on the raw accessor, a dropped depth, or a recurse/skip site that loses the parent_end clamp (guards overrunning_child_grup_in_a_skip_arm_seeks_to_parent_end, bounded_group_content_end_depth_cap_skip_is_parent_clamped pin fixtures, not every site).
• FLAG_COMPRESSED: data_size >= 4 checked before the subtraction; declared size is bounded by record_inflation_ceiling (min(64 MiB, max(64 KiB, compressed×2048)), from a seven-master census — worst real ratio 785.9:1, a Starfield SFTR, #4640; 512:1 rejected 82 vanilla records and dropped the whole plugin) and the decoder is held to take(declared + 1); mirrors byroredux_bsa::safety::inflate_bounded (#3410). Regression = either bound removed or the two implementations diverging. Output: /tmp/audit/esm/dim_1.md

Dimension 2: Sub-Record Byte Accounting (densest bug class)

Paths: crates/plugin/src/esm/sub_reader.rs, esm/records/**/*.rs, esm/cell/support.rs First step: git log --since=<last report> --name-only --format= -- crates/plugin/src/esm/records | sort -u (decoders touched since the last report), then re-derive their widths from the cited xEdit range. ESM analogue of /audit-nif Dim 1: a wrong field width shifts every later field and the record still "parses" with wrong numbers. Guard: records::test_support::tests::no_module_redeclares_a_local_subrecord_builder (fixture hygiene only — nothing here guards decode widths; since #5454, 29f8fa2ef, it flags any fn returning SubRecord built from a parameter 4-CC, not only fixed names). Checklist:

• Decoders read through SubReader; flag direct raw-slice indexing.
• The *_or_default family swallows short reads: fine for optional tails, a finding mid-fixed-layout (silent zeros). Classify every call site.
• Fixed-size sub-records check the declared length against the schema; version-gated tails are gated on GameKind or remaining length with an xEdit citation.
• Repeating rows (CTDA, CNTO, NVTR/NVEX → decode_nvtr_row/decode_nvex_row, LVLO): len / stride with an explicit remainder check; a non-zero remainder is a decode bug.
• rgb_color (3 B) vs rgba_color (4 B): swapped pairs shift every later byte. Colours are raw monitor-space floats — never flag a missing sRGB conversion (feedback_color_space).
• Known offset maps — verify against the code, not older reports: parse_race TES5 DATA starting pools at 36/40/44 (new fields land at ≥48; TES4/FO3NV and FO4/FO76 arms differ); WATR decode_data_fo3nv shared 0..28 prefix (wind speed/direction/amplitude/ frequency at 0/4/8/12, direction degrees-on-the-wire converted once), pinned by parse_watr_186_byte_record_reads_colors_at_40_44_48 and wind_direction_converts_shipped_degrees_on_the_fo3nv_dnam_arm (this field moved twice).
• Strings: terminator consumed exactly once; a missing terminator cannot read past the sub-record.
• Leveled lists (parse_leveled_list_for_game): FO76 split LVLO (4 B ref) + float LVLV/LVIV/LVCV companions only under GameKind::Fallout76; the legacy row accepts ≥8 bytes (Oblivion omits Count → default 1) and LVLD bit 0x80 becomes LVLF 0x01, not chance-none 128 (#4638). A sub-8-byte legacy LVLO must never become a valid reference. Output: /tmp/audit/esm/dim_2.md

Dimension 3: FormID Remap, Load Order & ESL Space

Paths: crates/plugin/src/esm/reader.rs (FormIdRemap, GlobalSlot), esm/records/tests.rs, esm/records/common.rs, byroredux/src/cell_loader/load_order.rs First step: cargo test -p byroredux-plugin -- every_record_parser_takes_a_remap parsers_that_take_a_remap no_parser_with_a_remap remap_fid_has_exactly_one Guards: records::tests::all_record_parsers walks records/ at test time and requires every pub fn parse_* to take a remap parameter or sit in EXEMPT_NO_U32_READS (mechanically re-verified) / EXEMPT_JUSTIFIED (written non-FormID reason); parsers_that_take_a_remap_actually_use_it; remap_fid_has_exactly_one_definition; no_parser_with_a_remap_in_scope_passes_an_identity_remap. The cell/ tier is guarded structurally (remap is a required parameter of read_form_id). Review new exemption entries in the diff — each is a human decision, not a proof. What the guards cannot see — the class keeps recurring in three shapes: (1) an unremapped field inside a shared decoder several parsers call (CommonNamedFields::from_subs_with_remap, #4067); (2) a GRUP label that encodes a FormID (DIAL topic-children label vs remapped DIAL id, #4079 — check every label-dispatch site like a sub-record field); (3) a HashMap<u32, _> in EsmIndex keyed by, or compared against, a raw plugin-local id. Inverse shape (4) — a non-FormID u32 routed into remap_fid (only 0 short-circuits, so every row warns through the out-of-range arm on a plugin with masters): xEdit wbFormIDCk([…, FFFF]) fields go through remap_fid_or_sentinel, and Oblivion EFID (a wbChar4 effect code resolved via magic_effects_by_code) through the game-gated remap_efid (records/common.rs; 9b099b31f, #5075/#5076); PKIN VNAM is xEdit's integer Version, stored raw as PkinRecord.version (0d436e642, #5422, pinned by pkin_vnam_version_stays_raw_under_remap). A new sentinel-bearing field, char4 code or plain integer calling remap_fid inline is the regression. SCOL/PKIN FLTR is a wbString filter path: both parsers store filter: String via read_zstring with no remap_fid (fixed in 136048a95, #5493; pinned by pkin_fltr_filter_path_stays_raw_under_remap + parse_scol_fltr_decodes_the_filter_path). CTDA param_1 is remapped only for functions whose first parameter is a FormID: condition.rs::param1_is_form_id mirrors the scripting catalog by raw function index (rows for fn 56/71/74 were missing until 722c06a76, #5637; M47.2 added the location/keyword/ relationship/quest-variable rows); param2_is_form_id is the second-parameter twin (fn 605/181/ 576/606/608 — everywhere else param_2 is a literal); the drift guard lives in the scripting crate (param1_form_id_table_matches_the_condition_catalog) — a new catalogued FormID-param function needs its row. Checklist:

• GlobalSlot::Regular keeps 24 bits; GlobalSlot::Light (0xFE space) packs a 12-bit sub-index and keeps only the low 12 object-id bits (0x0FFF masks on both sides); GlobalSlot::Medium (0xFD, Starfield) packs an 8-bit sub-index + 16-bit object id. The TES4 master bits are per game (#4639, read_file_header): Starfield small 0x100 / medium 0x400, Skyrim SE + FO4 light 0x200, every other game none — a 0x200 test on Starfield (Update) or a pre-ESL game is the regression. allocate_global_slot (load_order.rs) must keep the three spaces disjoint.
• FormIdRemap::remap arms: raw 0 → 0 (null sentinel, must not become a live ESL id); self-reference (mod_index == master_slots.len()); in-range master; standalone with no masters (pass through, debug — the vanilla Oblivion 0x01 artifact, #1308; must NOT be "fixed" into a clamp — two forms would collide in EsmIndex); out-of-range with masters (pass through, warn).
• Master list read in file order; a missing master fails diagnosably, not as a silently shifted slot table.
• Multi-plugin is live (--master repeatable → parse_esm_with_load_order); parse_esm passes None. Verify every embedded FormID in a newly-touched parser goes through remap_fid. The guard walk sees only pub/pub(crate)/pub(super) fn parse_* in records/ (files named tests.rs and #[cfg(test)] modules excised) — decode_* / from_subs* helpers and cell/ are outside it.
• Parallel walk (#3813, parse_record_indexes_in_load_order_with_archive): walks run on the rayon pool, but slot allocation, remap construction, .STRINGS loads and the merge_from fold stay on the calling thread in load order — fold order, never completion order. Guard: load_order_parallel_tests::parallel_walk_matches_the_inline_walk_on_a_localized_master_chain. Output: /tmp/audit/esm/dim_3.md

Dimension 4: Record Schema Dispatch & Coverage

Paths: crates/plugin/src/esm/records/{parse,index,items,container,actor_value_derive,load_screen}.rs, records/dispatch_*.rs, records/misc/*.rs, crates/plugin/src/equip.rs First step: cargo test -p byroredux-plugin -- dispatch_handled_fourccs every_index_map_is_a_category Guards: records::tests::dispatch_handled_fourccs_matches_the_live_dispatch_arms (DISPATCH_HANDLED_FOURCCS ↔ the live match in parse.rs; era-gated arms count as handled, PDCL is deliberately absent; LCTN/LCRT/RELA are routed through dispatch_misc_stub into typed maps since M47.2 — parse.rs's DISPATCH_HANDLED_FOURCCS doc still says LCTN has no arm, that prose is stale); index::tests::every_index_map_is_a_category_or_a_recorded_exclusion (every EsmIndex map is a categories() row — map_category! or a hand-written row recognized by its count closure, like dialogues — or a reasoned exclusion: record_types, the derived generic_greeting_form cache); cell::plugin_loading_doc_pin_tests::the_documented_esm_cell_index_lists_every_field and …::the_audio_record_split_matches_the_dispatcher (docs ↔ code). Checklist:

• Build the live matrix per record type: typed decode / minimal stub (parse_minimal_esm_record, EDID+FULL — dispatch_misc_stub.rs also hosts typed decoders: LSCR, CLOT/CCRD/CMNY → items) / skipped. Report the delta against record_type_catalog as coverage, not bugs. A stub must advance the reader correctly; the unknown-record path skips by declared size and never warns per record on a vanilla master.
• Per-game schema splits within one record (ARMO/WEAP/AMMO DATA, BOD2 vs BMDT vs Skyrim's pre-BOD2 BODT — 8 or 12 B, same leading biped mask, read in both ARMO and ARMA since 479414ffe (#5358; every Skyrim.esm ARMA authors it, so BOD2-only decoding zeroed all 766 masks), SCOL/PKIN/TXST, FO76 LVLO) switch on GameKind. Oblivion's 4-byte ARMO BMDT is a u16 Biped Flags + General Flags byte — the mask is the u16 only (a8e37e5fd, #5696; a u32 read put General Flags in bits 16-23 on 661 of 996 armors); FO3/FNV keep the u32. ACRE is not Oblivion-only (FO3 ships 3,349 ACRE vs 2,154 ACHR) — flag any new per-game gate on it.
• Consumables / items decode contract (decode only; consumption is /audit-gameplay): ALCH effect chains via parse_alch_for_game; MgefRecord.instant_restoration_av via parse_mgef_for_game; Oblivion parse_clot → ItemRecord; IMOD/CCRD/CMNY carried as items; LVLI multi-pick (flag 0x04) vs single-pick highest-eligible, pinned on the shipped FNV master. expand_leveled_loot retains unknown terminal ids and saturates counts — check it agrees with the decoder's LeveledEntry semantics.
• LSCR (parse_lscr, header flags via extract_records_with_flags): LNAM stores grid Y before X; malformed known fields land in malformed_fields rather than producing an unrestricted screen; truncated fixed fields are safe and visible.
• TPLT "Use Stats" resolves each absent stat down the chain to the deepest record that authors it (resolve_inherited_field, #4086; TPLT_MAX_DEPTH 6) — the terminal outranks a shallower record and a one-hop chain is unchanged. Check new stat fields join the per-field walk instead of comparing only the chain ends.
• EsmIndex::merge_from: last-write-wins matches Bethesda override semantics; game is only adopted when other.total() > 0 (a failed-parse EsmIndex::default() must not relabel the load order as FO3/FNV, #3403); character_rules is first-non-NONE wins. Exception — dialogues (168b81322, #5375): an override DIAL replaces only the header fields and folds its INFOs into the master's list by FormID (same id in place, new id after its PNAM predecessor), and the prune arm drops Deleted-INFO tombstones from every topic; whole-record extend erased 8.5–9.9k FNV INFOs per DLC. An override's PNAM == 0 run keeps authored file order through one per-override contribution cursor (fold_infos_into_topic, 5356c8780, #5494 — the first contribution goes to the front, later ones follow the previous; the run's position relative to the master's heads is an unsourced engine choice). Since 0c2bd4d6d (#5644) the fold is one pass over a FormID → node map; fold_info_into_topic_reference is the test-only one-at-a-time twin and batched_info_fold_matches_the_one_at_a_time_fold pins that the two agree. Top-level maps merge through categories(); EsmCellIndex::merge_from destructures exhaustively (#4904 — a .. there is the regression that dropped landscape_grasses).
• M47.2 added typed maps: locations (LCTN, misc/location.rs), location_ref_types (LCRT), relationships (RELA, misc/relationship.rs), condition_forms (Starfield CNDF), keywords (KYWD EDID only), SNDR into the sounds map via parse_sndr (soun.rs), RACE FO4 SRAC/SADD/SAKD/SGNM/SAPT/STKD/SRAF subgraph data, KWDA on CommonNamedFields, PERK entry bodies (PerkEntry/PerkEntryBody, EPFT/EPFD per the xEdit layout), and a "Use Base Data" template chain terminal (ResolvedNpc::base_data). The EsmIndex::categories() count is pinned in records::tests (109 at HEAD) — read the live number there; each new map must be a category row or a recorded exclusion.
• actor_value_derive.rs is the CHARAL feed — formulas belong to /audit-character.
• Settled decodes — verify they hold, do not re-derive: INAM is one FormID array (#3356); CREA CNAM is not a class (#3383); FACT rank ladder (#3338); ARMO contributes every race-matching ARMA (#3357), MOD3 is the female mesh (#3414); a REFR tombstone removes the placement wherever it lives (#3362); FO76 HEDR is patch-dependent — 279.0 on the 2026-09-20 patch, never pin it (#3405, #4643); DIAL quest ownership reads QSTI or QNAM (Skyrim authors QNAM; parse_dial); FO3/FNV/Oblivion INFOs also carry their own owning quest in InfoRecord.quest (QSTI, remapped, 23,247/23,247 FNV INFOs; dbc07e8f0, #5271 — Skyrim+/FO4 author none, 0 = use the topic's ownership); INFO DATA is typed InfoDataHeader (info_type / next_speaker / flags1 / flags2; Goodbye = Flags 1 bit 0) and Skyrim's 8-byte DATA lands raw in skyrim_data (25b678106, #5295); SMBN/SMEN/SMQN decode into story_manager_nodes (misc/story_manager.rs, #5366 closed — the SM dispatches live): SNAM is the previous sibling (xEdit Previous Node; 846e4a6dd, #5385 — the same-parent census holds in both directions and cannot settle it), SMQN RNAM is stored hours × 24 and decoded ÷ 24 (xEdit scale 1/24; a621d5352, #5386 — node HNAM stays raw), and XNAM/MNAM/HNAM/QNAM/FNAM/UNAM + DNAM 0x2/0x40000 are named from xEdit (5489cbe65, #5420; per-quest FNAM/UNAM live on SmQuestLink beside the NNAM/RNAM they follow — a node-level field let each later quest overwrite the last, 0edd1dede, #5515); INFO Flags 1 bit 5 = Random End (random_end, 0436bea5c, #5397); REGN WNAM is the owning worldspace (worldspace_form, remapped), never a weather, and REGN CNAM is xEdit-undefined with zero vanilla occurrences (bd052048a, #5421); NPC_.WNAM is the per-NPC skin ARMO (worn_skin, remapped, no game gate — pre-Skyrim ships none; edb5fbdfe, #5359); Oblivion RACE's body-section ICON run (INDX restarts at 0 past NAM1) lands in body_part_textures (1b45763fa, #5487); Starfield WTHS decodes the REFL/RDIF reflection schema only, not instance values (weather_settings.rs, #5364; the instance-value reader is open tracker #5627; the DIFF value walk is depth-capped at MAX_NESTING_DEPTH 64, 02187c7f9, #5687, pinned by hostile_self_referential_diffs_decline_at_the_depth_cap): DIFF is (u16 field index, inline value) pairs to the 0xFFFF terminator and USRD/MAPC join the instance census (f0f8dceef, #5514; real-data pins 163 in-range indices / 47 USRD); the CDB builtin ids live in one table (1f56d5742, #5615); FO76 LSCR decodes on the modern (FO4-shape) arm incl. BNAM → icon (47f927cbf, #5345); FO3/FNV PKDD Dialogue Type is the u32 at offset 16, and Oblivion PKDT (4 B) / PTDT (12 B) legacy shapes are accepted (dae08000d, #5492/#5504); FO3/FNV non-auto-calc NPCs keep their authored DATA SPECIAL in NpcRecord::data_attributes (4957536ba, #5338); FO4 NPC_ template flags resolve per flag through template_actors (TPTA, 13 entries in xEdit wbTemplateFlags order, 0 = use TPLT; 99c22a8db, #5498); MSWP CNAM is the Color Remapping Index palette row (color_remap_index, 0b2ffed89, #5497); MGEF DATA offsets/flags are named constants in misc/magic.rs's mgef_data (abe8d7e96, #5614).
• equip.rs::main_body_bit FO76/Starfield arms are a provisional inference (PROVISIONAL (#4074), pinned by fo76_and_starfield_arms_are_marked_provisional) — known and marked; report only if the marker is removed without an xEdit citation. Output: /tmp/audit/esm/dim_4.md

Dimension 5: CELL / WRLD Walkers & Placement Data

Paths: crates/plugin/src/esm/cell/**/*.rs, esm/records/misc/world.rs, esm/records/spatial_units.rs First step: git log --since=<last report> --format='%h %cs %s' -- crates/plugin/src/esm/cell crates/plugin/src/esm/records/misc/world.rs Checklist:

• Cell child groups: type 6 is the Cell Children container; 8 = Persistent, 9 = Temporary, 10 = Visible Distant nest inside it (#4169 — earlier legends said 6/8/9). PlacedRef.group_type is re-derived at each nested GRUP in parse_refr_group_inner (only the nested position accepts 10; at CELL/WRLD level 10 is Quest Children). No consumer reads it yet — verify it stays populated per-scope, not that a consumer exists.
• Interior and exterior CELL sub-record walkers share one decode, CellSubrecordFields::absorb (cell/helpers.rs, #5309) — a field added to only one walker's arm is the regression. All three walkers depth-bounded (see Dim 1): parse_cell_group, parse_wrld_children, parse_refr_group.
• Placement header flags (f87490826, #4813/#4814): PlacedRef.initially_disabled = 0x800 on every placement type; PlacedRef.starts_dead = 0x200 on ACHR gated on EsmVariant::Tes5Plus; starts_unconscious = 0x2000 on ACHR, FO4/FO76/Starfield only (#5017). The placement bit is not the corpse marker on every game, and each other game is settled at its own layer: Oblivion = base NPC_/CREA header 0x80000 (base_actor_starts_dead, dispatch_actor.rs, Oblivion-gated, #5013); FO3/FNV = base DATA health ≤ 0 (NpcRecord::starts_dead, #5005 — 0x80000 is not a marker there, and XRGD is a ragdoll pose, not a death signal) plus the script-killed idiom (717f39a82, #5223 — a dismember-family trigger's XLKR target; FO3/FNV XLKR is 4 B, the target FormID alone, vs TES5's 8 B keyword+target — a len >= 8 gate silently dropped every FO3/FNV link). A zero placement starts_dead means "no placement-level marker", not "alive"; the cell loader ORs both (byroredux/src/cell_loader/references/mod.rs → apply_starts_dead). Flag any per-game gate that reads one of these bits on a game whose xEdit list does not define it.
• Starfield metric → 70/m lift (records/spatial_units.rs::normalize, called once at the end of each plugin's walk in parse.rs): positions, light radii, XCLL/LGTM fog/fade + SF height-fog (#5002; the 20-field lighting tail decodes once in cell::decode_starfield_lighting_tail and the height-fog lift is the shared starfield_heights, 9dbd59b8b, #5346), WTHR fog distances (only when fog_distances_authored — an FNAM-less weather keeps the unlifted 10 000 default, ec75b1439, #5301, pinned by starfield_wthr_without_fnam_keeps_the_unlifted_fog_defaults) + height-fog tail (#5001/#5134), water heights, WATR DNAM lengths ×70 and per-metre absorption ÷70 — only for offsets the record authored (#5151, 24cb577d2), LAND heights, NAVM vertices, XRGD ragdoll-pose offsets (5f1a862be, #5299; Euler stays wire-valued). FO76 is BU-native except the shared-decoder WATR absorption lane, its only lift (#5169). Three Starfield WATR DNAM lane families (noise-UV tiles, displacement simulator, normal falloff) are deliberately not lifted — unit unsettled, pinned by starfield_watr_defers_the_unclassified_dnam_lanes; the LGTM + cell-XCLL lift is pinned through parse_esm by starfield_index_lifts_lgtm_and_xcll_lighting_distances (2dab4ff48, #5170/#5171, records/spatial_units_tests.rs). Check new Starfield distance fields join it, dimensionless fields (XSCL, Euler) stay out, decoder defaults for an unauthored field are never lifted, and no path normalizes an index twice.
• M47.2 placement/base fields, all remapped: REFR XAPR (activate parent + delay, XAPD Parent Activate Only), XMRK→FNAM map-marker flags, per-reference XEZN (PlacedRef.encounter_zone_form); base-object DEST/DSTD → DestructionData. ECZN DATA is per game (parse_eczn(.., game, ..): FO3/FNV 8 B, Skyrim/FO4/Starfield add the LCTN and max level; xEdit wbECZN). EsmCellIndex::cell_by_form_id is a lazily-built O(1) lookup (cell_form_id_lookup, #5489) that merge_from resets — a CELL-map edit after the first call leaves it stale.
• Lighting-template inheritance is per-field; "absent" and "authored zero" stay distinct.
• CELL XCCM is per-game (3b28dca71, #5463): TES4/FO3/FNV = Climate (CLMT) → CellData.climate_override; TES5/FO4 = "Sky/Weather from Region" (REGN) → sky_region (xccm_targets_region, cell/helpers.rs; decoded, no consumer yet; FO76/Starfield keep the CLMT reading, no verified xEdit definition). Guards parse_cell_fo3nv_xccm_populates_climate_override, parse_cell_tes5_fo4_xccm_is_a_region_not_a_climate. Regression = a REGN id reaching climate_override.
• XCLL is size- and game-validated: xcll_canonical_sizes(game); the ≥92-byte ambient-cube arm fires only for Skyrim/FO4/FO76 (Starfield has its own ≥108 arm) — a non-canonical 92+ XCLL on Oblivion/FO3NV keeps base + per-field reads and warns (guard: the cell test parse_cell_non_canonical_92plus_xcll_on_pre_skyrim_games_stays_out_of_the_ambient_cube). Parsed-but-unconsumed tail fields are parked in docs/engine/lighting-from-cells.md.
• LIGH LightData: falloff_exponent 0.0 is a sentinel resolved per layout generation at the translation boundary (canonical_light_falloff_exponent, byroredux/src/systems/light_anim.rs) — the parser must store authored values verbatim. Starfield light shape is the DAT2+56 Light Type enum (starfield_light_type: 0 omni, 1 shadow spot, 2 non-shadow spot); 0x200 is Focus Spotlight Beam, not a shape bit. DAT2 is gated on LIGH (an AMMO DAT2 must not synthesize light data).
• XCLW water height is tri-state: absent → inherit WRLD default; finite → override; INT_MIN / FLT_MAX sentinel → suppress (gated_water_height in esm/cell/helpers.rs + water_height_is_explicit; docs/engine/watal.md).
• Exterior grid XCLC, worldspace parenting and selective-inheritance flags (wrld.rs): a child inherits only the flagged categories. Oblivion authors no PNAM, so parse_wrld_group stamps land/LOD/water/climate inherit bits on every Oblivion child (67afa4b95, #5374 — pre-FO3 "child ⟹ inherit all"; the flag-less duplicate fallback was deleted in 65cadde2f, #5516, so the stamp is the only copy — pinned by oblivion_child_gets_the_inherit_all_stamp_and_eras_stay_real); an authored zero PNAM on FO3+ must stay zero.
• parse_land_record: quadrant/layer counts and splat rows are fixed-stride. An ATXT with no following VTXT must flush with alpha: None (pending_atxt, #4078; measured 14× on Oblivion.esm). LTEX.GNAM is an array of grasses, kept in authored order into landscape_grasses by parse_ltex_group (#4642; last-wins was the bug).
• FO4 precombine CELL sub-records (CellSubrecordFields::absorb): the XCRI tail is ref_count / 2 × (ref FormID, bake hash) pairs → CellData.absorbed_ref_bakes (the skip set); XPRI is the disjoint previs list, validated and not stored (777351ec1, #5484 — the two were inverted, double-drawing every baked STAT/SCOL). Guards parse_cell_xcri_pairs_remap_and_keep_their_bake_hash, parse_wrld_exterior_cell_captures_precombined_xcri_xpri.
• Starfield TXST: an unmodelled slot warns once (#4438), not per record.
• Navmesh: classic NVTR/NVEX and packed NVNM (decode_nvnm, NVNM_MAX_DIVISOR) yield the same NavmRecord through shared row decoders; the cursor refuses to pass the blob end; retained-raw-on-failure is diagnosable, not a silent success. Output: /tmp/audit/esm/dim_5.md

Dimension 6: Localized Strings (Skyrim+ .STRINGS family)

Paths: crates/plugin/src/esm/strings_table.rs, esm/records/common.rs (StringsTableGuard, lstring readers), byroredux/src/cell_loader/load_order.rs (table loading) First step: cargo test -p byroredux-plugin strings_table Checklist:

• The TES4 localized flag (0x80) — not "looks like a small integer" — decides literal vs u32 string id. lstring id 0 means "no string" (empty, never the <lstring 0x…> placeholder, #4072); only a genuinely unresolved id yields the placeholder.
• .STRINGS has no length prefix; .DLSTRINGS/.ILSTRINGS do (has_length_prefix). A flag/data disagreement warns loudly (declared length vs NUL offset, ±1 band, #4178) instead of yielding shifted strings.
• Missing string files degrade to "no string" without panic or per-form warn spam; a localized plugin that resolves zero tables logs a diagnostic (#4073, load_order.rs).
• Tables and the localized flag are thread-locals: since the parallel walk (#3813) the caller only loads tables (load_string_tables) and each walk installs its own StringsTableGuard on the walking thread. A guard installed on the caller yields <lstring 0x…> placeholders under the pool.
• The language token is not the file-name segment: Skyrim spells it out (dawnguard_english.strings), FO4/FO76/Starfield use a short tag (Fallout4_en.STRINGS). language_candidates expands both; check it exists before reporting the defect (two audits re-derived it before it was filed, #4168).
• Decode is UTF-8-first with a cp1252 fallback and that order is load-bearing (#4170: English tables carry real cp1252 bytes, localized tables are real UTF-8). A flat cp1252 decode is the regression; the fallback is not a bug.
• Loose files are found case-insensitively before the archive fallback (load_with_archive, #4176) — a case-mismatched mod override must beat the archive. Output: /tmp/audit/esm/dim_6.md

Dimension 7: EsmIndex → ECS Handoff & the Redux-Native Tier

Paths: crates/plugin/src/{record,datastore,resolver,manifest,equip}.rs, esm/records/index.rs; consumers byroredux/src/cell_loader/references/, byroredux/src/npc_spawn.rs First step: grep -rn 'resolve_entity_by_global_form_id\|find_by_form_id' byroredux/src | head -20 Checklist:

• EsmIndex is a session-long bag of HashMap<u32, _>; nothing evicts it. Check growth on a large load order against docs/engine/memory-budget.md (RAM, not VRAM).
• Sample high-traffic Option<u32> FormID fields (SCRI, RNAM, CNAM, PKID, XEZN, teleport XTEL): the consumer must resolve via resolve_entity_by_global_form_id, not a raw World::find_by_form_id.
• equip.rs biped-slot constants: BMDT vs BOD2 vs FO4 bit meanings differ; each block cites its xEdit definition; slot → addon_index (AddonData::addon_index) matches equipment_system. equip_template_tests.rs covers template equip resolution.
• Redux-native tier: audit for rot (compiles against the current Record shape; docs consistent with docs/engine/plugin-loading.md) and dead-but-documented API. "Unused" is not a bug on its own — but #5609 (open) records that DataStore + DependencyResolver + PluginManifest have no production consumer while four docs present them as the live load path; cite it rather than re-filing. Output: /tmp/audit/esm/dim_7.md

Dimension 8: Real-Data Validation

Paths: crates/plugin/examples/, crates/plugin/tests/parse_real_esm.rs, byroredux/src/{list_cells,sf_smoke}.rs First step: cargo run --release -p byroredux-plugin --example esm_dim8_coverage -- <master.esm> (one master at a time) Checklist:

• Per --game: records seen / decoded / stubbed / skipped and unknown sub-record codes per record type (esm_dim8_coverage emits the TSV; esm_dim8_bench gives parse time
  • EsmIndex totals; other probes: sf_smoke, probe_form, dump_record_subs, weather_coverage_census — ls crates/plugin/examples). Unknown-subrecord share is the coverage signal per-game audits never compute across the whole file.
• A decode rate that drops between games is a schema-split suspect — correlate with Dim 4 GameKind arms. Compare Starfield against the --sf-smoke resolve-rate baseline; a drop is a regression, not a new finding.
• Report parse time and peak RSS per master (ESM parse cost is on every cell load's critical path; NIF parse cost is /audit-performance).
• No windowed engine launch (feedback_no_parallel_engine_launch); example binaries and default cargo test only (see Phase 1 step 4 on --ignored). Output: /tmp/audit/esm/dim_8.md

Phase 3: Merge

1. Read all /tmp/audit/esm/dim_*.md; combine into docs/audits/AUDIT_ESM_<TODAY>.md:
   • Executive Summary — findings by severity; coverage posture; which games' real data was actually parsed.
   • Record Coverage Matrix — record type × game × {decoded, stubbed, skipped, unknown-subrecords}. The durable artifact; keep it even with no findings.
   • Findings — grouped by severity, deduplicated.
   • Cross-Audit Pointers — /audit-<game> Dim 1, /audit-scripting (VMAD), /audit-character (AVIF/class), /audit-physics (collision-relevant placement), /audit-exterior, /audit-gameplay, /audit-parsers.
2. Deduplicate against the per-game reports read in Phase 1 — a finding already filed under an /audit-<game> ESM dimension is Existing: #NNN, not new.

Phase 4: Cleanup

rm -rf /tmp/audit/esm; tell the user the report is ready; suggest /audit-publish docs/audits/AUDIT_ESM_<TODAY>.md (domain label esm-plugin; plus the matching game:* when specific to one title's records).