diff --git a/.claude/review-manifests/review-2026-07-30-package-audit.md b/.claude/review-manifests/review-2026-07-30-package-audit.md
index 0d5e9f31..b8302ec4 100644
--- a/.claude/review-manifests/review-2026-07-30-package-audit.md
+++ b/.claude/review-manifests/review-2026-07-30-package-audit.md
@@ -536,10 +536,10 @@ All verified unreferenced in `src/`:
 | `cli/progress.py:25-39`, `70-92`, `142-163` | `create_progress`, `update`, `IsomerProgressCallback` | test-only; `best_energy` never assigned, so `make_panel:136-137` is unreachable |
 | `utils/file_ops.py:352-366` | `housekeeping_helper` | test-only |
 | `ASE/thermo.py:197-209` | `mol2atoms` | dead, while its body is inlined at `:225-228` and `:443-446` |
-| `exceptions.py:41,72,81,89` | 4 classes | never raised; see M29 |
+| `exceptions.py:41,72,81,89` | 4 classes | ~~never raised~~ **WRONG as of 2026-08-03**: only `ModelError` is never raised directly, and deliberately -- `ModelLoadError`/`NumericalError` subclass it and `cli/errors.py` maps it to exit code 5 so both inherit that code. "Never raised" != "unused" for a base class |
 | `constants.py:10,11,38,46,79` | 5 constants | `SUPPORTED_MODELS` is the very whitelist M50 shows written four times; `STANDARD_PRESSURE` unused while `thermo.py:308-309` hardcodes `101325`; `check_connectivity` hardcodes `1.25`/`1.1` at `chemistry.py:331,336` instead of the two constants named for them |
 | `model_wrapper.py:60-85`, `120-174` | legacy `name` API + `_legacy_forward` (55 lines) | says "removed in Auto3D v2.0"; package is **3.5.0** |
-| `ASE/thermo.py:159` | `model_name` param | accepted, never read, yet `calc_thermo:459` passes it explicitly |
+| `ASE/thermo.py:159` | `model_name` param | ~~accepted, never read~~ **WRONG as of 2026-08-03**: `Calculator` reads `self.model_name` and passes it to `to_model_species`; the C3/C4 species-conversion work made it live |
 
 `encode_smiles`/`decode_smiles`/`housekeeping_helper`/`filter_unique` are in `utils/__init__.py` `__all__`, and the four exceptions are in `docs/source/api.rst:86-92` — removals are API-breaking and need a deprecation cycle.
 
diff --git a/docs/superpowers/follow-ups-after-4.0.0-remediation.md b/docs/superpowers/follow-ups-after-4.0.0-remediation.md
index a1645407..a951d975 100644
--- a/docs/superpowers/follow-ups-after-4.0.0-remediation.md
+++ b/docs/superpowers/follow-ups-after-4.0.0-remediation.md
@@ -121,13 +121,35 @@ present and dead:
 | **already deleted** by earlier phases | `pad_molecular_batch`, `cli/progress` `create_progress`, `IsomerProgressCallback` |
 | **not dead — M53 wrong** | `utils/stereo_check` (6 live uses), `cli/results` `FailedMolecule` + `print_failures` (live from `run.py` since the C6/C7 reconciliation work — the finding's "run.py admits failures is always []" no longer holds), `ASE/thermo` `mol2atoms`, `STANDARD_PRESSURE`, `isomers/parallel_embed` |
 | **genuinely dead — deleted** | `utils_file.py` (whole module), `count_from_output`, `encode_smiles`, `decode_smiles`, `housekeeping_helper`, and 3 constants (`BOND_STRETCH_TOLERANCE`, `COLLISION_THRESHOLD`, `SUPPORTED_MODELS`) |
-| **unresolved — line numbers stale** | `exceptions.py` "4 classes never raised" (line 41 is `OptimizationError`, raised 3x, so the cited lines no longer point at what the finding describes); `ASE/thermo` `model_name` param (the `model_wrapper` legacy `name` API is **DONE 2026-08-03**) |
+| **resolved 2026-08-03 — also wrong** | `exceptions.py` "4 classes never raised"; `ASE/thermo`'s `model_name` param |
+| **resolved 2026-08-03 — was right, removed** | `model_wrapper`'s legacy `name` API |
 
 Net: **256 lines removed from `src/`, 167 from `tests/`** — not the ~450 of `src/`
 the finding claimed, because a third of it was gone and half of the rest is alive.
 
-The three unresolved entries need their own pass; the audit's line numbers cannot
-be used to find them.
+**M53 is now closed.** The last three entries were resolved by checking source
+rather than line numbers:
+
+- **`model_wrapper`'s legacy `name` API** — right, and removed. The deprecation
+  said "removed in Auto3D v2.0"; the package reached 3.0.0 with it in place.
+- **`ASE/thermo`'s `model_name` parameter** — **wrong**. `Calculator` reads
+  `self.model_name` at `thermo.py:536`, passing it to `to_model_species`. The
+  C3/C4 species-conversion work made it live after the audit was written.
+- **`exceptions.py`'s "4 classes never raised"** — **wrong**, and the shape of the
+  claim is the problem. Only `ModelError` is never raised directly, and that is
+  deliberate: `ModelLoadError` and `NumericalError` subclass it, and
+  `cli/errors.py:29` maps it to exit code 5 precisely so both subclasses inherit
+  that code. Deleting it would break the exit-code scheme the 3.0.0 release
+  documents. "Never raised" is not the same as "unused" for a base class — an
+  audit that greps for `raise X` cannot tell them apart.
+
+**Final tally for M53: of 13 entries, 4 were real.** Three had already been done,
+six were wrong when re-checked, and the remaining four were deleted in #135/#136.
+Nothing further to remove. The single most useful lesson is that a dead-code
+finding decays faster than any other kind: the same work that fixes defects revives
+symbols the audit saw as dead (`mol2atoms`, `STANDARD_PRESSURE`, `FailedMolecule`,
+`print_failures`, `model_name`), and a mechanical sweep would have deleted five
+live ones.
 
 ## What the remediation closed