assets builder tools (#39)

Reviewed-on: #39
Reviewed-by: xtul <mpiasecki720@protonmail.com>

cmd/crucible-assets/main.go

@@ -0,0 +1,11 @@
+// Command crucible-assets is the standalone assets builder (equivalent to
+// `crucible assets`). A single-token binary keeps consumer wrapper scripts simple.
+package main
+
+import (
+	"os"
+
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/dispatch"
+)
+
+func main() { os.Exit(dispatch.RunBuilder("assets", os.Args[1:])) }

docs/command-surface.md

@@ -22,6 +22,13 @@ aliases.
 | `topdata` | `convert` | Convert between 2DA and native JSON/module formats. |
 | `wiki` | `build` | Render wiki page drafts from compiled topdata. |
 | `wiki` | `deploy` | Deploy generated wiki pages to NodeBB. |
+| `assets` | `compile` | Compile ASCII `.mdl` models to binary in place. |
+| `assets` | `convert` | Convert textures to/from NWN DDS (flips vertically). |
+| `assets` | `upscale` | Upscale textures through an installed backend. |
+| `assets` | `check-mdl` | Report uncompiled ASCII `.mdl` and model-name mismatches. |
+| `assets` | `fix-mdl` | Lowercase `.mdl` names and rewrite model identity to match. |
+| `assets` | `check-dupes` | Report runtime-name (basename) collisions across dirs. |
+| `assets` | `clean-dupes` | Delete clean-tree files whose basename collides with primary. |
 
 `crucible-depot` remains registered but unwired. It fails closed with exit `70`
 and never emits placeholder artifacts.

docs/superpowers/specs/2026-07-12-crucible-assets-builder-design.md

@@ -0,0 +1,342 @@
+# Crucible `assets` builder — design
+
+Date: 2026-07-12
+Status: approved, pre-implementation
+
+## Goal
+
+Fold the NWN:EE asset tools out of two standalone toolkits into Crucible as a
+new self-contained builder, `crucible assets`:
+
+- from the Python toolkit (`nwnee-asset-processing`) — model compile, texture
+  convert, texture upscale. Those scripts are references only; broken as-is and
+  carrying a heavy config/staging/report layer that we drop.
+- from `sow-assets-manifest/scripts/` — the model-name and duplicate-name
+  integrity tools (`check-ascii-mdl.sh`, `fix-mdl-model-names.sh`,
+  `check-duplicate-names.sh`, `clean-duplicate-names.sh`). These are ported into
+  Go and the shell drivers removed; `sow-assets-manifest` calls
+  `./crucible.sh assets …` through its bootstrap wrapper instead.
+
+Seven commands:
+
+- `crucible assets compile` — compile every ASCII `.mdl` in a directory to
+  binary, in place.
+- `crucible assets convert` — convert every texture in a directory to NWN:EE
+  DDS (or back to PNG/TGA), flipping vertically **every time** so a DDS is
+  always upside-down relative to its source.
+- `crucible assets upscale` — upscale every texture in a directory through
+  whatever upscaling backend is installed.
+- `crucible assets check-mdl` — report uncompiled ASCII `.mdl` files and
+  model-name mismatches (read-only).
+- `crucible assets fix-mdl` — lowercase `.mdl` filenames and rewrite ASCII
+  model/root names to match each file's stem.
+- `crucible assets check-dupes` — report runtime-name (basename) collisions
+  across directories.
+- `crucible assets clean-dupes` — delete files from a "clean" tree whose
+  basename collides with anything in a "primary" tree.
+
+## Principles
+
+- **No configuration files. Arguments only.** No `processing/` staging dirs, no
+  discards, no YAML, no reports. Operates in place on the target directory.
+- **Discover, don't configure.** External tools (the NWN engine, ImageMagick, an
+  upscaler) are found on `PATH` and at standard install locations. Each has a
+  single override flag when discovery is not enough.
+- **Fail closed, never fake** (Crucible rule #1). A missing backend is a clear
+  error naming what to install and a non-zero exit — never a placeholder
+  artifact.
+- **Simplify.** Drop the reference tools' padding / power-of-two / `nwn-safe` /
+  explicit-format knobs (convert auto-picks DXT1 vs DXT5) and the small-texture
+  staging (upscale). These can return later if wanted.
+
+## Architecture
+
+A new self-contained builder that follows the existing `depot` pattern exactly
+(delegates straight to its own internal package, bypassing the legacy
+`internal/app` surface):
+
+- `internal/assets/run.go` — `func Run(args []string, stdout, stderr io.Writer,
+  getenv func(string) string) int`. Parses the subcommand
+  (`compile|convert|upscale|check-mdl|fix-mdl|check-dupes|clean-dupes`) and
+  dispatches. Returns a sysexits-style code.
+- `internal/assets/` — one file per command plus small shared helpers
+  (recursion/file-selection, external-command runner, backend discovery).
+- `cmd/crucible-assets/main.go` — one-line shim:
+  `func main() { os.Exit(dispatch.RunBuilder("assets", os.Args[1:])) }`.
+- `internal/dispatch`:
+  - one `Registry` entry for `assets` (`Wired: true`) listing the seven
+    commands with `Usage`/`Options`;
+  - extend the direct-delegate branch that today reads
+    `if b.Name == "depot" && b.Wired` so `assets` also routes to
+    `assets.Run(...)` instead of the legacy `app.Run`.
+- `docs/command-surface.md` — seven visible-command rows.
+- `wrappers/consumers.txt` / wrappers are unchanged (no new consumer; the
+  consumers listed already vendor the wrapper).
+
+### Shared helpers (`internal/assets`)
+
+- `walk(roots, exts)` — collect files under each root (recursive by default)
+  whose extension is in `exts`, case-insensitively. Reject nothing fancy; these
+  are arguments the caller chose.
+- `run(cmd, args...)` — thin `exec.Command` wrapper capturing combined output,
+  returning `(output, error)`. A single indirection point so tests can observe
+  invocations. cwd and env overrides passed as needed.
+- `look(names...)` — return the first name found via `exec.LookPath`, or the
+  first path that exists from a supplied list of candidates. Used by every
+  backend discovery.
+
+### Shared MDL name module (`internal/assets/mdl`)
+
+A pure-Go port of `mdl-name-lib.sh` + `mdl-scan.awk`, no external tools. One
+place three commands share (`compile`'s pre-check, `check-mdl`, `fix-mdl`):
+
+- `IsASCII(path)` — NUL in the first 256 bytes → binary; else the leading
+  keyword must be `#`/`newmodel`/`node`/`setsupermodel`. Mirrors `mdl_is_ascii`.
+- `ExpectedName(path)` — the file stem (sans `.mdl`).
+- `CheckNames(path) []Mismatch` — for an ASCII model, report header-token
+  mismatches (`newmodel`, `setsupermodel`, `beginmodelgeom`, `endmodelgeom`,
+  `donemodel`, `newanim`, `doneanim` — case-insensitive vs the stem) and the
+  geometry **base node** mismatch (the node inside `beginmodelgeom` whose parent
+  is `null`; empty if none). Mirrors `mdl_check_model_name` + `mdl_base_name`.
+- `FixNames(in) (out []byte, changed bool)` — rewrite only the model identity:
+  the header tokens above, plus the base node's declaration / any `parent` /
+  `animroot` pointing at the *old* base name → the expected name. Animation bone
+  names and supermodel animroots are left untouched so inheritance keeps working.
+  Mirrors `mdl_fix_model_name` byte-for-byte in intent.
+
+Detection must stay identical to the awk classifier so behavior does not drift
+while `import.sh` still runs the awk version (see Consumer migration).
+
+## `crucible assets compile <dir>…`
+
+Usage: `crucible assets compile [--nwn <install>] [--non-recursive] <dir>…`
+
+Recursively find ASCII `.mdl` files under each `<dir>` and compile each to a
+binary `.mdl` in place (the compiled result replaces the source).
+
+The NWN:EE engine is the only real ASCII→binary MDL compiler, so this drives it
+exactly as the reference does:
+
+- **Discovery.** User data dir is fixed on Linux at
+  `~/.local/share/Neverwinter Nights` (holds the flat `development/` and
+  `modelcompiler/` folders the engine uses). The `nwmain` binary is found by
+  probing standard install roots, first hit wins:
+  - `~/.local/share/Steam/steamapps/common/Neverwinter Nights/bin/linux-x86/nwmain-linux`
+  - GOG: `~/GOG Games/Neverwinter Nights Enhanced Edition/.../nwmain-linux`
+  - Beamdog install dirs.
+  - `--nwn <install>` overrides (path to the install root or directly to the
+    binary).
+- **Headless.** The engine is a GUI binary. If there is no `DISPLAY` and
+  `xvfb-run` is present, wrap the call:
+  `xvfb-run -a --server-args=-screen 0 1024x768x24 nwmain-linux compilemodel <stem>`.
+- **Per model (one at a time — the engine's `development/` and `modelcompiler/`
+  folders are flat and single-slot):**
+  1. Skip if the file is not ASCII (binary/compiled `.mdl`) — reported, not an
+     error.
+  2. Copy source into `development/<name>`.
+  3. Run `nwmain-linux compilemodel <stem>` with cwd = the binary dir.
+  4. Collect the compiled artifact from `modelcompiler/` matched
+     case-insensitively by stem.
+  5. Move it back over the source path, lowercased.
+  6. Clean the temp files created in `development/` and `modelcompiler/`.
+- **Collisions.** A pre-existing `development/<name>` or `modelcompiler/<stem>`
+  aborts that model before any mutation.
+
+Exit: non-zero if any model fails; each failure prints a short excerpt of the
+engine log (`~/.local/share/Neverwinter Nights/logs/nwengineLog.txt`) as
+advisory diagnostics.
+
+Dropped vs reference: internal-name-mismatch pre-checks and the
+`Model Names Differ` fail rule are kept (cheap, prevents silent wrong output),
+using the shared `internal/assets/mdl` module — `compile` aborts a model whose
+names differ and tells the user to run `crucible assets fix-mdl`. It does **not**
+auto-fix (kept separate, by decision). The discard-manifest, dry-run/report
+layer, and `processing/in|out` staging are dropped.
+
+## `crucible assets convert <dir>…`
+
+Usage: `crucible assets convert [--to dds|png|tga] [--backend <path>]
+[--non-recursive] <dir>…`
+
+Recursively convert textures in place. `--to` defaults to `dds`. The source set
+is every texture under the roots whose format is not already the target, among
+`{.dds, .png, .tga}`.
+
+**Every conversion flips vertically exactly once.** Converting to DDS produces
+an upside-down DDS (NWN's convention); converting a DDS back to PNG/TGA flips it
+upright again. The flip is unconditional — it is the defining behavior, not a
+policy.
+
+Backend: ImageMagick (`magick`), one tool for decode + flip + encode across all
+three formats:
+
+- to DDS: `magick <src> -flip -define dds:mipmaps=<n> -define
+  dds:compression=<dxt1|dxt5> <dst>.dds`, choosing DXT1 when the source is
+  opaque and DXT5 when it has alpha (detected with `magick identify`).
+- from DDS: `magick <src>.dds -flip <dst>.<png|tga>`.
+- `--backend <path>` points at a different ImageMagick-compatible binary or a
+  dedicated encoder for higher-quality DXT (e.g. compressonator); default is
+  `magick`.
+
+The original file is replaced in place — canonical DDS is the point. Exit
+non-zero if any file fails.
+
+Dropped vs reference: `--pad-color`, POT/legacy-safe/`nwn-safe`/`--strict`
+sizing, explicit `--format`, alpha-detect toggles, discard staging. Auto DXT
+selection replaces the format knobs.
+
+## `crucible assets upscale <dir>…`
+
+Usage: `crucible assets upscale [--scale N] [--backend <path>]
+[--non-recursive] <dir>…`
+
+Recursively upscale textures in place.
+
+- **Backend discovery**, first found wins: `upscayl-bin`, `upscayl`,
+  `realesrgan-ncnn-vulkan`, `waifu2x-ncnn-vulkan`. These share a compatible
+  ncnn-vulkan CLI shape (`-i <in> -o <out> -s <scale>`). `--backend <path>`
+  overrides.
+- `--scale N` default 4.
+- Backends operate on PNG; real NWN textures are DDS, so for a `.dds` input the
+  command reuses the convert helpers: dds→png (flip), run the backend, png→dds
+  (flip back) — yielding a correctly-flipped upscaled DDS. PNG/TGA inputs are
+  upscaled directly in place.
+- No backend found → fail closed with a message naming the supported backends.
+
+Dropped vs reference: min-dimension small-texture staging, the separate
+`--dds-backend` plumbing (it reuses convert), configured backend-path table.
+
+## `crucible assets check-mdl <path>…`
+
+Port of `check-ascii-mdl.sh`. Read-only. Each `<path>` is a file or a directory
+(recursed for `*.mdl`). For every model, using `internal/assets/mdl`:
+
+- report an **uncompiled ASCII** `.mdl` (a binary/compiled one is fine, skipped);
+- report every model-name mismatch (header tokens and geometry base node) with
+  file, line, the offending token, and the expected stem.
+
+Exit non-zero if any ASCII model or mismatch is found; zero and an `OK` line
+otherwise. No mutation.
+
+## `crucible assets fix-mdl [--dry-run] <path>…`
+
+Port of `fix-mdl-model-names.sh`. For each `*.mdl` under the paths:
+
+1. **Lowercase the filename** if it is not already lowercase (`mv`; abort that
+   file on a case-collision with an existing target).
+2. For ASCII models with a name mismatch, rewrite the model identity in place
+   via `mdl.FixNames` (binary models are skipped — the engine owns those).
+
+`--dry-run` reports every "would lowercase" / "would fix" without touching disk.
+Prints a per-file log and a final `no broken mdl model names found` when clean.
+
+Selection optimization from the reference is preserved: a file is a fix
+candidate only if it needs a content fix (name mismatch) or a filename
+lowercase, so the expensive per-file read/rewrite runs only on the few that
+matter, not the whole tree.
+
+## `crucible assets check-dupes <dir>…`
+
+Port of `check-duplicate-names.sh`'s **directory mode only**. Read-only. NWN
+packs hak entries by basename, not path, so files at different paths with the
+same basename (case-insensitively) silently clobber on pack. Across all `<dir>`
+args, report any two files whose lowercased basename matches.
+
+Exit non-zero if any collision is found.
+
+The script's `--manifests` mode (hak-scoped collisions read from `assets/*.yml`)
+is **not** ported here — it inspects manifest structure, not files on disk, so
+it belongs with the manifest/depot tooling. It moves in the follow-up spec (see
+Out of scope); until then `sow-assets-manifest` keeps
+`check-duplicate-names.sh` solely for that mode.
+
+## `crucible assets clean-dupes [--dry-run] <primary> <clean>`
+
+Port of `clean-duplicate-names.sh`. Deletes files from the `<clean>` tree whose
+basename collides (case-insensitively) with any file in the `<primary>` tree.
+Mutates only `<clean>`. Same rule as `check-dupes` directory mode, but resolves
+the collision by removal instead of reporting.
+
+- Refuses to run if `<primary>` and `<clean>` overlap (either contains the
+  other), matching the script's guard.
+- `--dry-run` reports every "would delete" without removing.
+
+Exit zero on success with a count of removed (or would-remove) files.
+
+## Consumer migration (`sow-assets-manifest`)
+
+`sow-assets-manifest` already ships the `crucible` bootstrap wrapper
+(`crucible.sh`) and uses `crucible depot` from its Makefile, so it resolves a
+released `crucible` with zero extra setup.
+
+- **Delete** the three fully-folded driver scripts: `scripts/check-ascii-mdl.sh`,
+  `scripts/fix-mdl-model-names.sh`, `scripts/clean-duplicate-names.sh`.
+- **Repoint** the Makefile targets to the wrapper:
+  - `check-mdl` → `./crucible.sh assets check-mdl …`
+  - `fix-mdl` → `./crucible.sh assets fix-mdl [--dry-run] …`
+  - `check-dupes` — its directory scan → `./crucible.sh assets check-dupes …`;
+    the `check-duplicate-names.sh --manifests` line stays as-is.
+  - `clean-dupes` → `./crucible.sh assets clean-dupes [--dry-run] <PRIMARY> <CLEAN>`
+- **Keep for now:**
+  - `scripts/check-duplicate-names.sh` — kept **only** for its `--manifests`
+    mode, still called by the `check` and `haks` targets. Its directory mode is
+    superseded by `crucible assets check-dupes`. Ported and deleted in the
+    follow-up.
+  - `scripts/mdl-scan.awk` and `scripts/mdl-name-lib.sh` — still sourced by
+    `import.sh` for its batched pre-import gate (~28× faster than per-file, on a
+    hot path). They retire in the follow-up too. Because both the awk classifier
+    and the Go `mdl` module must agree, the port keeps detection byte-for-byte
+    identical (a shared fixture set checks this).
+
+Nothing in `sow-assets-manifest` is committed by this project's plan except the
+script deletions and Makefile edits; that repo's change lands as its own commit
+once the new `crucible` release with `assets` is available.
+
+## Out of scope — follow-up spec
+
+Moving the **depot-interacting pipeline** into `crucible depot` is a separate
+project with its own spec
+(`2026-07-12-crucible-depot-pipeline-migration-design.md`). It covers
+`import.sh`, `sync-assets.sh`, `export.sh`, the inline mdl gate, and the
+`check-duplicate-names.sh --manifests` manifest-collision check. When that lands:
+its gate uses the in-process `internal/assets/mdl` module, and
+`scripts/mdl-scan.awk`, `scripts/mdl-name-lib.sh`, and
+`scripts/check-duplicate-names.sh` are all deleted. This spec deliberately stops
+at the standalone, file-on-disk integrity tools to keep one focused plan.
+
+## Error handling
+
+- Missing external tool (engine, `magick`, upscaler) → non-zero exit, message
+  names the tool and how to get it. Never a faked artifact. The pure-Go
+  integrity commands (`check-mdl`, `fix-mdl`, `check-dupes`, `clean-dupes`) need
+  no external tool.
+- Per-file failures are collected and printed as a summary line at the end; the
+  command exits non-zero if any file failed but still processes the rest.
+- Report commands (`check-mdl`, `check-dupes`) exit non-zero when they *find*
+  problems — that is their contract as CI/pre-import gates, not a tool error.
+- Unknown subcommand / bad flags → usage error, exit 64.
+
+## Testing
+
+Go tests in `internal/assets`:
+
+- flag/subcommand parsing and usage errors;
+- backend discovery against a fabricated `PATH` (temp dir with stub
+  executables) — asserts first-match ordering and the `--backend` override;
+- `walk` recursion and extension filtering, including `--non-recursive`;
+- one real convert round-trip using `magick` (present in the dev shell):
+  encode a small PNG to DDS and back, asserting the pixels are vertically
+  flipped after a single conversion and restored after the round trip.
+- `internal/assets/mdl`: table-driven fixtures — ASCII vs binary detection,
+  each header-token mismatch, the base-node mismatch, and `FixNames` producing
+  a model that then passes `CheckNames`. A parity fixture set shared in intent
+  with `mdl-scan.awk` so the Go port and the still-present awk agree.
+- `check-dupes`/`clean-dupes`: temp trees asserting basename-collision
+  detection (case-insensitive), the overlap guard, and `--dry-run` mutating
+  nothing.
+
+External engine/upscaler calls are exercised through the `run` indirection with
+a stub in tests; they are not invoked for real in CI.
+
+`make check` must stay green; add an `assets` expectation to `make smoke` for
+the wired exit.

docs/superpowers/specs/2026-07-12-crucible-depot-pipeline-migration-design.md

@@ -0,0 +1,90 @@
+# Crucible `depot` pipeline migration — design (charter / draft)
+
+Date: 2026-07-12
+Status: **draft — needs its own brainstorming pass before implementation.**
+Depends on: `2026-07-12-crucible-assets-builder-design.md` (the `assets` builder
+and `internal/assets/mdl` module) landing first.
+
+This is a scoping charter, not an implementation-ready design. The scripts it
+covers are nontrivial and lean heavily on `sow-assets-manifest/scripts/lib.sh`
+(~35 KB). A full design requires studying `lib.sh` and the manifest format in
+depth; that work happens in this spec's own brainstorming before any code.
+
+## Why this exists
+
+`sow-assets-manifest` is the last consumer still carrying real builder logic in
+shell. The `assets` spec folded its standalone integrity tools into Crucible but
+deliberately left the **depot-interacting pipeline** behind, because those
+scripts read/write the content-addressed depot and the asset manifests — depot
+domain, and a bigger lift. This charter completes the migration so
+`sow-assets-manifest` becomes what the other consumers already are: a thin
+caller of released `crucible` binaries with no vendored toolkit logic.
+
+## What moves into `crucible depot`
+
+The depot builder already owns `status/push/verify/get/pull`. This adds the
+authoring side:
+
+| Script | Proposed command | What it does today |
+| --- | --- | --- |
+| `import.sh` (318 lines) | `crucible depot import <edit-dir> [prefix…]` | Import an edit tree into the depot + manifests: sticky per-path member assignment, new paths to the tail member, per-category `max_bytes` rebalance (spill overflow forward, no full repack), a local stat-cache to skip unchanged files, batched hashing + parallel `depot_put_many`. |
+| `sync-assets.sh` (61 lines) | `crucible depot sync <tree> [prefix…]` | Full reconcile = import + prune manifest entries whose path no longer exists (scoped by prefix when given). Delegates to `import.sh`. |
+| `export.sh` (96 lines) | `crucible depot export [glob] [--hak m] [--restype ext] --to <dir>` | Materialize a manifest-selected subset out of the depot into a clean edit tree (category paths preserved, no metadata). |
+| `check-duplicate-names.sh --manifests` | `crucible depot check-dupes` (name TBD) | Hak-scoped basename collisions read from `assets/*.yml` (`.assets[].path` grouped by `.assets[].hak`). Manifest-structure check, not files on disk. |
+
+The inline **pre-import mdl gate** in `import.sh` (batched `mdl-scan.awk` pass
+that aborts on an H/B model-name mismatch before any blob is hashed/uploaded)
+is reimplemented with the in-process `internal/assets/mdl` module from the
+`assets` spec — same H/B contract, no subprocess.
+
+## What retires when this lands
+
+Deleted from `sow-assets-manifest/scripts/` once the commands above are wired
+and the Makefile is repointed:
+
+- `import.sh`, `sync-assets.sh`, `export.sh`
+- `mdl-scan.awk`, `mdl-name-lib.sh` (only remaining consumer was `import.sh`)
+- `check-duplicate-names.sh` (its directory mode already superseded by
+  `crucible assets check-dupes`; the `--manifests` mode moves here)
+- whatever else in `lib.sh` becomes dead once the above are gone (assess during
+  design — `lib.sh` also serves `build-haks.sh`, `pack-haks.sh`, `promote.sh`,
+  etc., which are **not** in scope here, so `lib.sh` likely shrinks, not dies)
+
+Makefile targets `import`, `sync`, `haks` (its sync/import/dupe steps), `export`
+repoint to `./crucible.sh depot …`.
+
+## Known hard parts (resolve in brainstorming)
+
+- **Manifest read/write parity.** Byte-stable output, member `max_bytes`
+  rebalance semantics, sticky path→member assignment. Must match the current
+  awk/`lib.sh` behavior or diff-review of manifests becomes noise. Crucible
+  already parses these manifests (`internal/pipeline`, hak build) — reuse, don't
+  reinvent.
+- **Depot backends.** `import`/`export` drive bunny/cdn/local through
+  `lib.sh`'s `depot_put_many`/`depot_require_write` (incl. the
+  `BUNNY_STORAGE_PASSWORD` prompt and cdn→bunny write normalization). Crucible's
+  `internal/depot` already speaks these backends for pull/push — the authoring
+  side should share that client, not a second implementation.
+- **Stat-cache.** `import.sh`'s `.cache/import/<target>/<cat>.tsv` skip-unchanged
+  optimization is the dominant re-import speedup. Decide whether Crucible
+  reproduces it, replaces it (content-addressing already dedupes uploads), or
+  drops it with a measured justification.
+- **Throughput.** The shell versions are already batched to avoid per-file
+  forks; a Go port should be at least as fast (in-process, no forks) — verify,
+  don't assume.
+- **Scoping semantics.** Prefix-scoped import/prune (segment-boundary match) and
+  export glob matching (`**`/`*`/literal dots, no shell expansion) must port
+  exactly.
+
+## Out of scope
+
+The HAK build/pack/promote/publish scripts (`build-haks.sh`, `pack-haks.sh`,
+`promote.sh`, `publish-release*.sh`, `hak-artifact-record.sh`) and their
+`lib.sh` support. `crucible hak build` already exists; whether these thin
+release wrappers also migrate is a separate question, not this charter.
+
+## Next step
+
+Brainstorm this charter into a full design: read `lib.sh` and the manifest
+format, settle the hard parts above, then write the implementation-ready spec
+and plan. Do not implement from this document.

internal/assets/checkmdl.go

@@ -0,0 +1,67 @@
+package assets
+
+import (
+	"flag"
+	"fmt"
+	"io"
+
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/assets/mdl"
+)
+
+// mdlExt is the file set shared by the mdl commands.
+var mdlExt = map[string]bool{".mdl": true}
+
+// runCheckMDL reports uncompiled ASCII .mdl files and model-name mismatches.
+// Read-only. Exit exitFail if any problem is found.
+func runCheckMDL(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("check-mdl", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	nonRecursive := fs.Bool("non-recursive", false, "do not descend into subdirectories")
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	paths := fs.Args()
+	if len(paths) == 0 {
+		fmt.Fprintln(stderr, "assets check-mdl: usage: check-mdl <path>...")
+		return exitUsage
+	}
+
+	files, err := walk(paths, mdlExt, !*nonRecursive)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets check-mdl:", err)
+		return exitUsage
+	}
+
+	fail := false
+	for _, f := range files {
+		ascii, err := mdl.IsASCII(f)
+		if err != nil {
+			fmt.Fprintln(stderr, "assets check-mdl:", err)
+			return exitTool
+		}
+		if ascii {
+			fmt.Fprintf(stderr, "uncompiled ascii mdl: %s\n", f)
+			fail = true
+		}
+		mismatches, err := mdl.CheckNames(f)
+		if err != nil {
+			fmt.Fprintln(stderr, "assets check-mdl:", err)
+			return exitTool
+		}
+		expected := mdl.ExpectedName(f)
+		for _, m := range mismatches {
+			if m.Line == 0 {
+				fmt.Fprintf(stderr, "%s: mdl model-name mismatch: root node is %s, expected %s\n", f, m.Got, expected)
+			} else {
+				fmt.Fprintf(stderr, "%s: mdl model-name mismatch: line %d: %s is %s, expected %s\n", f, m.Line, m.What, m.Got, expected)
+			}
+			fail = true
+		}
+	}
+	if fail {
+		fmt.Fprintln(stderr, "check-mdl: found broken or uncompiled .mdl file(s)")
+		return exitFail
+	}
+	fmt.Fprintln(stdout, "check-mdl: OK")
+	return exitOK
+}

internal/assets/checkmdl_test.go

@@ -0,0 +1,32 @@
+package assets
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCheckMDL(t *testing.T) {
+	dir := t.TempDir()
+	// Uncompiled ASCII model with a name mismatch.
+	bad := filepath.Join(dir, "foo.mdl")
+	if err := os.WriteFile(bad, []byte("newmodel wrong\nbeginmodelgeom wrong\nendmodelgeom wrong\ndonemodel wrong\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	var out, errw bytes.Buffer
+	if code := runCheckMDL([]string{dir}, &out, &errw); code != exitFail {
+		t.Fatalf("bad mdl exit = %d, want %d\n%s", code, exitFail, errw.String())
+	}
+
+	// A binary (compiled) model is fine.
+	good := t.TempDir()
+	if err := os.WriteFile(filepath.Join(good, "bar.mdl"), []byte("\x00\x00compiled binary blob"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	out.Reset()
+	errw.Reset()
+	if code := runCheckMDL([]string{good}, &out, &errw); code != exitOK {
+		t.Fatalf("binary mdl exit = %d, want %d\n%s", code, exitOK, errw.String())
+	}
+}

internal/assets/compile.go

@@ -0,0 +1,190 @@
+package assets
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/assets/mdl"
+)
+
+// runCompile compiles ASCII .mdl models to binary in place, one at a time (the
+// engine's development/ and modelcompiler/ folders are flat, single-slot).
+func runCompile(args []string, stdout, stderr io.Writer, getenv func(string) string) int {
+	fs := flag.NewFlagSet("compile", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	nwn := fs.String("nwn", "", "path to the NWN install root or nwmain-linux binary")
+	nonRecursive := fs.Bool("non-recursive", false, "do not descend into subdirectories")
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	dirs := fs.Args()
+	if len(dirs) == 0 {
+		fmt.Fprintln(stderr, "assets compile: usage: compile [--nwn INSTALL] <dir>...")
+		return exitUsage
+	}
+
+	home := getenv("HOME")
+	userData := filepath.Join(home, ".local", "share", "Neverwinter Nights")
+	dev := filepath.Join(userData, "development")
+	mc := filepath.Join(userData, "modelcompiler")
+
+	nwmain := findNWMain(*nwn, home)
+	if nwmain == "" {
+		fmt.Fprintln(stderr, "assets compile: nwmain-linux not found — pass --nwn <install> "+
+			"(Steam/GOG/Beamdog install root or the nwmain-linux binary)")
+		return exitTool
+	}
+	binDir := filepath.Dir(nwmain)
+
+	// Headless wrap: no DISPLAY + xvfb-run present -> run under a virtual X.
+	var wrap []string
+	if getenv("DISPLAY") == "" {
+		if xvfb := look("xvfb-run"); xvfb != "" {
+			wrap = []string{xvfb, "-a", "--server-args=-screen 0 1024x768x24"}
+		}
+	}
+
+	files, err := walk(dirs, mdlExt, !*nonRecursive)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets compile:", err)
+		return exitUsage
+	}
+
+	failed := false
+	for _, src := range files {
+		if err := compileOne(src, binDir, nwmain, dev, mc, wrap, userData, stdout, stderr); err != nil {
+			fmt.Fprintf(stderr, "assets compile: %s: %v\n", src, err)
+			failed = true
+		}
+	}
+	if failed {
+		return exitFail
+	}
+	return exitOK
+}
+
+// findNWMain resolves the nwmain-linux binary from --nwn or standard roots.
+func findNWMain(override, home string) string {
+	if override != "" {
+		if fi, err := os.Stat(override); err == nil && !fi.IsDir() {
+			return override
+		}
+		cand := filepath.Join(override, "bin", "linux-x86", "nwmain-linux")
+		if fi, err := os.Stat(cand); err == nil && !fi.IsDir() {
+			return cand
+		}
+		return ""
+	}
+	return look(
+		filepath.Join(home, ".local/share/Steam/steamapps/common/Neverwinter Nights/bin/linux-x86/nwmain-linux"),
+		filepath.Join(home, "GOG Games/Neverwinter Nights Enhanced Edition/game/bin/linux-x86/nwmain-linux"),
+		filepath.Join(home, ".steam/steam/steamapps/common/Neverwinter Nights/bin/linux-x86/nwmain-linux"),
+	)
+}
+
+// compileOne compiles a single model. Binary models are reported and skipped
+// (not an error). A name-mismatched model is aborted with guidance.
+func compileOne(src, binDir, nwmain, dev, mc string, wrap []string, userData string, stdout, stderr io.Writer) error {
+	ascii, err := mdl.IsASCII(src)
+	if err != nil {
+		return err
+	}
+	if !ascii {
+		fmt.Fprintf(stdout, "skip (already compiled): %s\n", src)
+		return nil
+	}
+	mismatches, err := mdl.CheckNames(src)
+	if err != nil {
+		return err
+	}
+	if len(mismatches) > 0 {
+		return fmt.Errorf("model names differ from the file stem; run `crucible assets fix-mdl` first")
+	}
+
+	stem := mdl.ExpectedNameStem(src)
+	name := strings.ToLower(filepath.Base(src))
+	devFile := filepath.Join(dev, name)
+	// Collision guard: a pre-existing slot aborts before any mutation.
+	if _, err := os.Stat(devFile); err == nil {
+		return fmt.Errorf("development slot already occupied: %s", devFile)
+	}
+
+	data, err := os.ReadFile(src)
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(devFile, data, 0o644); err != nil {
+		return err
+	}
+	defer os.Remove(devFile)
+
+	// Run the engine with cwd = the binary dir.
+	cmd := append(append([]string{}, wrap...), nwmain, "compilemodel", stem)
+	if out, err := runner(binDir, nil, cmd[0], cmd[1:]...); err != nil {
+		printEngineLog(userData, stderr)
+		return fmt.Errorf("engine: %v: %s", err, strings.TrimSpace(string(out)))
+	}
+
+	// Collect the compiled artifact from modelcompiler/ (match by stem, any case).
+	compiled, err := findCompiled(mc, stem)
+	if err != nil {
+		printEngineLog(userData, stderr)
+		return err
+	}
+	defer os.Remove(compiled)
+
+	out, err := os.ReadFile(compiled)
+	if err != nil {
+		return err
+	}
+	// Move it back over the source path, lowercased.
+	dst := filepath.Join(filepath.Dir(src), name)
+	if err := os.WriteFile(dst, out, 0o644); err != nil {
+		return err
+	}
+	if dst != src {
+		_ = os.Remove(src)
+	}
+	fmt.Fprintf(stdout, "compiled: %s\n", dst)
+	return nil
+}
+
+// findCompiled returns the modelcompiler/ artifact whose stem matches (case-
+// insensitively).
+func findCompiled(mc, stem string) (string, error) {
+	entries, err := os.ReadDir(mc)
+	if err != nil {
+		return "", err
+	}
+	want := strings.ToLower(stem) + ".mdl"
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		if strings.ToLower(e.Name()) == want {
+			return filepath.Join(mc, e.Name()), nil
+		}
+	}
+	return "", fmt.Errorf("engine produced no compiled model for %q", stem)
+}
+
+// printEngineLog appends a short tail of the engine log as advisory diagnostics.
+func printEngineLog(userData string, stderr io.Writer) {
+	log := filepath.Join(userData, "logs", "nwengineLog.txt")
+	data, err := os.ReadFile(log)
+	if err != nil {
+		return
+	}
+	lines := strings.Split(strings.TrimRight(string(data), "\n"), "\n")
+	if len(lines) > 8 {
+		lines = lines[len(lines)-8:]
+	}
+	fmt.Fprintf(stderr, "  engine log tail (%s):\n", log)
+	for _, l := range lines {
+		fmt.Fprintf(stderr, "    %s\n", l)
+	}
+}

internal/assets/compile_test.go

@@ -0,0 +1,110 @@
+package assets
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCompileDrivesEngineAndReplacesInPlace(t *testing.T) {
+	home := t.TempDir()
+	userData := filepath.Join(home, ".local", "share", "Neverwinter Nights")
+	dev := filepath.Join(userData, "development")
+	mc := filepath.Join(userData, "modelcompiler")
+	for _, d := range []string{dev, mc} {
+		if err := os.MkdirAll(d, 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	// Fake nwmain binary for discovery via --nwn.
+	binDir := t.TempDir()
+	nwmain := filepath.Join(binDir, "nwmain-linux")
+	if err := os.WriteFile(nwmain, []byte("#!/bin/sh\n"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+
+	getenv := func(k string) string {
+		switch k {
+		case "HOME":
+			return home
+		case "DISPLAY":
+			return ":0" // pretend a display exists so no xvfb wrap is needed
+		}
+		return ""
+	}
+
+	// Stub the engine: writes a binary compiled model into modelcompiler/.
+	orig := runner
+	defer func() { runner = orig }()
+	runner = func(dir string, env []string, name string, args ...string) ([]byte, error) {
+		// args: compilemodel <stem>
+		stem := args[len(args)-1]
+		compiled := filepath.Join(mc, stem+".mdl")
+		return nil, os.WriteFile(compiled, []byte("\x00\x00compiled"), 0o644)
+	}
+
+	// Source tree with one ASCII model whose names already match its stem.
+	srcDir := t.TempDir()
+	src := filepath.Join(srcDir, "foo.mdl")
+	body := "newmodel foo\nbeginmodelgeom foo\n  node dummy foo\n    parent null\n  endnode\nendmodelgeom foo\ndonemodel foo\n"
+	if err := os.WriteFile(src, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	var stdout, stderr bytes.Buffer
+	code := runCompile([]string{"--nwn", nwmain, srcDir}, &stdout, &stderr, getenv)
+	if code != exitOK {
+		t.Fatalf("compile exit = %d\n%s", code, stderr.String())
+	}
+	// The source is now binary (the compiled artifact moved back over it).
+	data, err := os.ReadFile(src)
+	if err != nil {
+		t.Fatalf("compiled model missing: %v", err)
+	}
+	if string(data) != "\x00\x00compiled" {
+		t.Fatalf("source not replaced by compiled binary: %q", data)
+	}
+}
+
+func TestCompileAbortsOnNameMismatch(t *testing.T) {
+	home := t.TempDir()
+	if err := os.MkdirAll(filepath.Join(home, ".local", "share", "Neverwinter Nights", "development"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	binDir := t.TempDir()
+	nwmain := filepath.Join(binDir, "nwmain-linux")
+	if err := os.WriteFile(nwmain, []byte("#!/bin/sh\n"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	getenv := func(k string) string {
+		if k == "HOME" {
+			return home
+		}
+		if k == "DISPLAY" {
+			return ":0"
+		}
+		return ""
+	}
+	orig := runner
+	defer func() { runner = orig }()
+	engineCalled := false
+	runner = func(string, []string, string, ...string) ([]byte, error) {
+		engineCalled = true
+		return nil, nil
+	}
+
+	srcDir := t.TempDir()
+	// Internal name "wrong" != stem "foo": must abort before touching the engine.
+	if err := os.WriteFile(filepath.Join(srcDir, "foo.mdl"),
+		[]byte("newmodel wrong\ndonemodel wrong\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	var stdout, stderr bytes.Buffer
+	if code := runCompile([]string{"--nwn", nwmain, srcDir}, &stdout, &stderr, getenv); code != exitFail {
+		t.Fatalf("mismatch exit = %d, want %d", code, exitFail)
+	}
+	if engineCalled {
+		t.Fatal("engine should not run for a name-mismatched model")
+	}
+}

internal/assets/convert.go

@@ -0,0 +1,116 @@
+package assets
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var textureExts = map[string]bool{".dds": true, ".png": true, ".tga": true}
+
+// runConvert converts textures in place, flipping vertically exactly once per
+// conversion. --to defaults to dds. Files already in the target format are
+// skipped.
+func runConvert(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("convert", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	to := fs.String("to", "dds", "target format: dds|png|tga")
+	backend := fs.String("backend", "magick", "ImageMagick-compatible binary")
+	nonRecursive := fs.Bool("non-recursive", false, "do not descend into subdirectories")
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	target := strings.ToLower(*to)
+	if target != "dds" && target != "png" && target != "tga" {
+		fmt.Fprintln(stderr, "assets convert: --to must be dds, png, or tga")
+		return exitUsage
+	}
+	dirs := fs.Args()
+	if len(dirs) == 0 {
+		fmt.Fprintln(stderr, "assets convert: usage: convert [--to dds|png|tga] <dir>...")
+		return exitUsage
+	}
+
+	magick := look(*backend)
+	if magick == "" {
+		fmt.Fprintf(stderr, "assets convert: backend %q not found — install ImageMagick (magick)\n", *backend)
+		return exitTool
+	}
+
+	files, err := walk(dirs, textureExts, !*nonRecursive)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets convert:", err)
+		return exitUsage
+	}
+
+	targetExt := "." + target
+	failed := false
+	for _, src := range files {
+		srcExt := strings.ToLower(filepath.Ext(src))
+		if srcExt == targetExt {
+			continue // already in the target format
+		}
+		dst := strings.TrimSuffix(src, filepath.Ext(src)) + targetExt
+		var convErr error
+		if target == "dds" {
+			convErr = pngToDDS(magick, src, dst)
+		} else {
+			convErr = ddsToPNG(magick, src, dst) // works for any decodable source
+		}
+		if convErr != nil {
+			fmt.Fprintf(stderr, "assets convert: %s: %v\n", src, convErr)
+			failed = true
+			continue
+		}
+		if dst != src {
+			if err := os.Remove(src); err != nil {
+				fmt.Fprintf(stderr, "assets convert: %s: %v\n", src, err)
+				failed = true
+			}
+		}
+	}
+	if failed {
+		return exitFail
+	}
+	return exitOK
+}
+
+// ddsToPNG decodes src to dst (PNG/TGA by dst's extension), flipping vertically
+// once. The single flip is the defining NWN behavior.
+func ddsToPNG(magickBin, src, dst string) error {
+	if out, err := runner("", nil, magickBin, src, "-flip", dst); err != nil {
+		return fmt.Errorf("magick: %v: %s", err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+// pngToDDS encodes src to a DDS at dst, flipping vertically once and choosing
+// DXT1 for opaque images, DXT5 for images with alpha.
+func pngToDDS(magickBin, src, dst string) error {
+	compression := "dxt1"
+	if hasAlpha(magickBin, src) {
+		compression = "dxt5"
+	}
+	// ponytail: mipmaps rely on magick's default full chain (NWN wants a
+	// pyramid, which magick writes by default). Add `-define dds:mipmaps=N`
+	// here if a specific count is ever required.
+	out, err := runner("", nil, magickBin, src, "-flip",
+		"-define", "dds:compression="+compression, dst)
+	if err != nil {
+		return fmt.Errorf("magick: %v: %s", err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+// hasAlpha reports whether src has any non-opaque pixel, via `magick identify`.
+// On any probe error it assumes alpha (DXT5), the safe/lossless-alpha default.
+func hasAlpha(magickBin, src string) bool {
+	out, err := runner("", nil, magickBin, "identify", "-format", "%[opaque]", src)
+	if err != nil {
+		return true
+	}
+	return !strings.EqualFold(strings.TrimSpace(string(out)), "true")
+}

internal/assets/convert_test.go

@@ -0,0 +1,108 @@
+package assets
+
+import (
+	"bytes"
+	"image"
+	"image/color"
+	"image/png"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+// writeTestPNG writes a 16x16 image: top half red, bottom half blue. The size
+// and the half-way split keep every 4x4 DXT block a single flat color, so the
+// DXT1 round trip stays lossless and only the flip is under test. (A 4x4 image
+// is one mixed DXT block that magick's encoder collapses to a single color.)
+func writeTestPNG(t *testing.T, path string) {
+	t.Helper()
+	const n = 16
+	img := image.NewRGBA(image.Rect(0, 0, n, n))
+	for y := 0; y < n; y++ {
+		c := color.RGBA{255, 0, 0, 255} // red
+		if y >= n/2 {
+			c = color.RGBA{0, 0, 255, 255} // blue
+		}
+		for x := 0; x < n; x++ {
+			img.Set(x, y, c)
+		}
+	}
+	f, err := os.Create(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	if err := png.Encode(f, img); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func topRowIsBlue(t *testing.T, pngPath string) bool {
+	t.Helper()
+	f, err := os.Open(pngPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	img, err := png.Decode(f)
+	if err != nil {
+		t.Fatal(err)
+	}
+	r, _, b, _ := img.At(0, 0).RGBA()
+	return b > r // blue dominates the top-left after a flip
+}
+
+func TestConvertFlipsOnceAndRoundTrips(t *testing.T) {
+	magick := look("magick")
+	if magick == "" {
+		t.Skip("magick not on PATH")
+	}
+	dir := t.TempDir()
+	src := filepath.Join(dir, "tex.png")
+	writeTestPNG(t, src)
+
+	// Convert PNG -> DDS (in place: tex.png becomes tex.dds, original removed).
+	var out, errw bytes.Buffer
+	if code := runConvert([]string{"--to", "dds", dir}, &out, &errw); code != exitOK {
+		t.Fatalf("to-dds exit = %d\n%s", code, errw.String())
+	}
+	dds := filepath.Join(dir, "tex.dds")
+	if _, err := os.Stat(dds); err != nil {
+		t.Fatalf("dds not produced: %v", err)
+	}
+	if _, err := os.Stat(src); !os.IsNotExist(err) {
+		t.Fatal("source png was not replaced")
+	}
+
+	// Decode the DDS RAW (no extra flip) and confirm a single flip happened:
+	// the source top row was red, so the DDS top row must now be blue.
+	raw := filepath.Join(dir, "raw.png")
+	if err := exec.Command(magick, dds, raw).Run(); err != nil {
+		t.Fatalf("raw decode: %v", err)
+	}
+	if !topRowIsBlue(t, raw) {
+		t.Fatal("expected the DDS to be vertically flipped vs the source")
+	}
+
+	// Convert DDS -> PNG (another flip). Result should match the original.
+	out.Reset()
+	errw.Reset()
+	if code := runConvert([]string{"--to", "png", dir}, &out, &errw); code != exitOK {
+		t.Fatalf("to-png exit = %d\n%s", code, errw.String())
+	}
+	restored := filepath.Join(dir, "tex.png")
+	if topRowIsBlue(t, restored) {
+		t.Fatal("round trip did not restore the original orientation")
+	}
+}
+
+func TestConvertMissingBackendFailsClosed(t *testing.T) {
+	dir := t.TempDir()
+	writeTestPNG(t, filepath.Join(dir, "tex.png"))
+	var out, errw bytes.Buffer
+	code := runConvert([]string{"--backend", "/nonexistent/magick", dir}, &out, &errw)
+	if code != exitTool {
+		t.Fatalf("missing backend exit = %d, want %d", code, exitTool)
+	}
+}

internal/assets/dupes.go

@@ -0,0 +1,151 @@
+package assets
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+// allFiles returns every regular file under root (recursive).
+func allFiles(root string) ([]string, error) {
+	var out []string
+	err := filepath.WalkDir(root, func(p string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if !d.IsDir() {
+			out = append(out, p)
+		}
+		return nil
+	})
+	sort.Strings(out)
+	return out, err
+}
+
+// runCheckDupes reports files whose lower-cased basename collides across the
+// given dirs. Read-only. Exit exitFail if any collision is found.
+func runCheckDupes(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("check-dupes", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	dirs := fs.Args()
+	if len(dirs) == 0 {
+		fmt.Fprintln(stderr, "assets check-dupes: usage: check-dupes <dir>...")
+		return exitUsage
+	}
+
+	first := map[string]string{}
+	fail := false
+	for _, dir := range dirs {
+		if fi, err := os.Stat(dir); err != nil || !fi.IsDir() {
+			fmt.Fprintf(stderr, "assets check-dupes: no such dir: %s\n", dir)
+			return exitUsage
+		}
+		files, err := allFiles(dir)
+		if err != nil {
+			fmt.Fprintln(stderr, "assets check-dupes:", err)
+			return exitTool
+		}
+		for _, f := range files {
+			key := strings.ToLower(filepath.Base(f))
+			if prev, ok := first[key]; ok {
+				fmt.Fprintf(stderr, "runtime-name collision: %s collides with %s\n", f, prev)
+				fail = true
+			} else {
+				first[key] = f
+			}
+		}
+	}
+	if fail {
+		fmt.Fprintln(stderr, "check-dupes: found runtime-name collision(s)")
+		return exitFail
+	}
+	fmt.Fprintln(stdout, "check-dupes: OK")
+	return exitOK
+}
+
+// runCleanDupes deletes files from <clean> whose lower-cased basename collides
+// with any file in <primary>. Mutates only <clean>. Refuses to run if the two
+// trees overlap.
+func runCleanDupes(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("clean-dupes", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	dryRun := fs.Bool("dry-run", false, "report deletions without removing")
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	pos := fs.Args()
+	if len(pos) != 2 {
+		fmt.Fprintln(stderr, "assets clean-dupes: usage: clean-dupes [--dry-run] <primary> <clean>")
+		return exitUsage
+	}
+	primary, clean := pos[0], pos[1]
+	for _, d := range []string{primary, clean} {
+		if fi, err := os.Stat(d); err != nil || !fi.IsDir() {
+			fmt.Fprintf(stderr, "assets clean-dupes: no such dir: %s\n", d)
+			return exitUsage
+		}
+	}
+	primaryReal, err1 := filepath.EvalSymlinks(primary)
+	cleanReal, err2 := filepath.EvalSymlinks(clean)
+	if err1 != nil || err2 != nil {
+		fmt.Fprintln(stderr, "assets clean-dupes: cannot resolve dirs")
+		return exitTool
+	}
+	if overlaps(primaryReal, cleanReal) {
+		fmt.Fprintln(stderr, "assets clean-dupes: primary and clean dirs must not overlap")
+		return exitUsage
+	}
+
+	primaryFiles, err := allFiles(primary)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets clean-dupes:", err)
+		return exitTool
+	}
+	names := map[string]bool{}
+	for _, f := range primaryFiles {
+		names[strings.ToLower(filepath.Base(f))] = true
+	}
+
+	cleanFiles, err := allFiles(clean)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets clean-dupes:", err)
+		return exitTool
+	}
+	removed := 0
+	for _, f := range cleanFiles {
+		if !names[strings.ToLower(filepath.Base(f))] {
+			continue
+		}
+		if *dryRun {
+			fmt.Fprintf(stderr, "would delete clean-tree collision: %s\n", f)
+		} else {
+			if err := os.Remove(f); err != nil {
+				fmt.Fprintln(stderr, "assets clean-dupes:", err)
+				return exitTool
+			}
+			fmt.Fprintf(stderr, "deleted clean-tree collision: %s\n", f)
+		}
+		removed++
+	}
+	verb := "removed"
+	if *dryRun {
+		verb = "would remove"
+	}
+	fmt.Fprintf(stdout, "clean-dupes: %s %d file(s)\n", verb, removed)
+	return exitOK
+}
+
+// overlaps reports whether either directory contains the other (or they are
+// equal), using cleaned absolute-ish paths with a trailing separator.
+func overlaps(a, b string) bool {
+	as := a + string(filepath.Separator)
+	bs := b + string(filepath.Separator)
+	return strings.HasPrefix(as, bs) || strings.HasPrefix(bs, as)
+}

internal/assets/dupes_test.go

@@ -0,0 +1,80 @@
+package assets
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func touch(t *testing.T, path string) {
+	t.Helper()
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(path, []byte("x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestCheckDupes(t *testing.T) {
+	root := t.TempDir()
+	touch(t, filepath.Join(root, "tex", "Foo.tga"))
+	touch(t, filepath.Join(root, "plc", "foo.tga")) // basename collision (case-insensitive)
+
+	var out, errw bytes.Buffer
+	if code := runCheckDupes([]string{root}, &out, &errw); code != exitFail {
+		t.Fatalf("collision exit = %d, want %d\n%s", code, exitFail, errw.String())
+	}
+
+	clean := t.TempDir()
+	touch(t, filepath.Join(clean, "a.tga"))
+	touch(t, filepath.Join(clean, "sub", "b.tga"))
+	out.Reset()
+	errw.Reset()
+	if code := runCheckDupes([]string{clean}, &out, &errw); code != exitOK {
+		t.Fatalf("no-collision exit = %d, want %d\n%s", code, exitOK, errw.String())
+	}
+}
+
+func TestCleanDupes(t *testing.T) {
+	primary := t.TempDir()
+	clean := t.TempDir()
+	touch(t, filepath.Join(primary, "keep.tga"))
+	collide := filepath.Join(clean, "sub", "Keep.tga")
+	survive := filepath.Join(clean, "unique.tga")
+	touch(t, collide)
+	touch(t, survive)
+
+	// dry-run removes nothing.
+	var out, errw bytes.Buffer
+	if code := runCleanDupes([]string{"--dry-run", primary, clean}, &out, &errw); code != exitOK {
+		t.Fatalf("dry-run exit = %d\n%s", code, errw.String())
+	}
+	if _, err := os.Stat(collide); err != nil {
+		t.Fatal("dry-run deleted a file")
+	}
+
+	// real run deletes the collision, keeps the unique file.
+	out.Reset()
+	errw.Reset()
+	if code := runCleanDupes([]string{primary, clean}, &out, &errw); code != exitOK {
+		t.Fatalf("clean exit = %d\n%s", code, errw.String())
+	}
+	if _, err := os.Stat(collide); !os.IsNotExist(err) {
+		t.Fatal("collision file was not deleted")
+	}
+	if _, err := os.Stat(survive); err != nil {
+		t.Fatal("unique file was wrongly deleted")
+	}
+}
+
+func TestCleanDupesRejectsOverlap(t *testing.T) {
+	root := t.TempDir()
+	sub := filepath.Join(root, "child")
+	touch(t, filepath.Join(sub, "x.tga"))
+	var out, errw bytes.Buffer
+	if code := runCleanDupes([]string{root, sub}, &out, &errw); code != exitUsage {
+		t.Fatalf("overlap exit = %d, want %d", code, exitUsage)
+	}
+}

internal/assets/fixmdl.go

@@ -0,0 +1,103 @@
+package assets
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/assets/mdl"
+)
+
+// runFixMDL lowercases .mdl filenames and rewrites ASCII model identity to
+// match each file's stem. Binary models are skipped (the engine owns those).
+func runFixMDL(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("fix-mdl", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	dryRun := fs.Bool("dry-run", false, "report changes without touching disk")
+	nonRecursive := fs.Bool("non-recursive", false, "do not descend into subdirectories")
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	paths := fs.Args()
+	if len(paths) == 0 {
+		fmt.Fprintln(stderr, "assets fix-mdl: usage: fix-mdl [--dry-run] <path>...")
+		return exitUsage
+	}
+
+	files, err := walk(paths, mdlExt, !*nonRecursive)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets fix-mdl:", err)
+		return exitUsage
+	}
+
+	changed := 0
+	failed := false
+	for _, f := range files {
+		// 1. Lowercase the basename if needed.
+		//
+		// ponytail: 35k files are each read once here (CheckNames + the rewrite
+		// on candidates). The shell reference batched an awk pass to avoid
+		// per-file subprocess spawns; in Go a plain read is cheap, so the batch
+		// is not worth porting. If profiling ever shows this hot, parallelize
+		// the loop.
+		lower := f
+		if base := filepath.Base(f); base != strings.ToLower(base) {
+			lower = filepath.Join(filepath.Dir(f), strings.ToLower(base))
+			if _, err := os.Stat(lower); err == nil {
+				fmt.Fprintf(stderr, "assets fix-mdl: lowercase collision: %s -> %s\n", f, lower)
+				failed = true
+				continue
+			}
+			if *dryRun {
+				fmt.Fprintf(stdout, "would lowercase: %s -> %s\n", f, lower)
+			} else {
+				if err := os.Rename(f, lower); err != nil {
+					fmt.Fprintf(stderr, "assets fix-mdl: failed to lowercase %s: %v\n", f, err)
+					failed = true
+					continue
+				}
+				fmt.Fprintf(stdout, "lowercased: %s -> %s\n", f, lower)
+			}
+			changed++
+		}
+
+		// 2. Rewrite model identity if the (lowercased) file has a mismatch.
+		//    In dry-run the on-disk file is still the original path.
+		readPath := lower
+		if *dryRun && lower != f {
+			readPath = f
+		}
+		data, err := os.ReadFile(readPath)
+		if err != nil {
+			fmt.Fprintln(stderr, "assets fix-mdl:", err)
+			failed = true
+			continue
+		}
+		out, wasChanged := mdl.FixNames(data, mdl.ExpectedName(lower))
+		if !wasChanged {
+			continue
+		}
+		if *dryRun {
+			fmt.Fprintf(stdout, "would fix: %s\n", lower)
+		} else {
+			if err := os.WriteFile(lower, out, 0o644); err != nil {
+				fmt.Fprintln(stderr, "assets fix-mdl:", err)
+				failed = true
+				continue
+			}
+			fmt.Fprintf(stdout, "fixed: %s\n", lower)
+		}
+		changed++
+	}
+
+	if changed == 0 {
+		fmt.Fprintln(stdout, "no broken mdl model names found")
+	}
+	if failed {
+		return exitFail
+	}
+	return exitOK
+}

internal/assets/fixmdl_test.go

@@ -0,0 +1,48 @@
+package assets
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/assets/mdl"
+)
+
+func TestFixMDL(t *testing.T) {
+	dir := t.TempDir()
+	// Uppercase name + internal mismatch.
+	upper := filepath.Join(dir, "Foo.MDL")
+	body := "newmodel wrong\nbeginmodelgeom wrong\nendmodelgeom wrong\ndonemodel wrong\n"
+	if err := os.WriteFile(upper, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	// dry-run: nothing changes on disk.
+	var out, errw bytes.Buffer
+	if code := runFixMDL([]string{"--dry-run", dir}, &out, &errw); code != exitOK {
+		t.Fatalf("dry-run exit = %d\n%s", code, errw.String())
+	}
+	if _, err := os.Stat(upper); err != nil {
+		t.Fatal("dry-run renamed a file")
+	}
+
+	// real run: file is lowercased and its identity rewritten to match.
+	out.Reset()
+	errw.Reset()
+	if code := runFixMDL([]string{dir}, &out, &errw); code != exitOK {
+		t.Fatalf("fix exit = %d\n%s", code, errw.String())
+	}
+	lowered := filepath.Join(dir, "foo.mdl")
+	if _, err := os.Stat(lowered); err != nil {
+		t.Fatalf("file was not lowercased: %v", err)
+	}
+	mismatches, err := mdl.CheckNames(lowered)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(mismatches) != 0 {
+		data, _ := os.ReadFile(lowered)
+		t.Fatalf("model still has mismatches after fix: %+v\n%s", mismatches, data)
+	}
+}

internal/assets/helpers.go

@@ -0,0 +1,84 @@
+// Package assets is the crucible `assets` builder: NWN:EE model/texture tools
+// that operate in place on a target directory. Mirrors internal/depot's
+// Run(args, stdout, stderr, getenv) shape and bypasses the legacy internal/app
+// surface entirely.
+package assets
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+// runner is the single external-command indirection so tests can observe and
+// stub every engine / ImageMagick / upscaler invocation. dir is the working
+// directory ("" = inherit); env replaces the child environment when non-nil.
+var runner = func(dir string, env []string, name string, args ...string) ([]byte, error) {
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	if env != nil {
+		cmd.Env = env
+	}
+	return cmd.CombinedOutput()
+}
+
+// walk collects files under each root whose lower-cased extension is in exts. A
+// root that is itself a matching file is included. recursive controls descent
+// into subdirectories. Results are sorted and deduplicated.
+func walk(roots []string, exts map[string]bool, recursive bool) ([]string, error) {
+	seen := map[string]bool{}
+	var out []string
+	add := func(p string) {
+		if exts[strings.ToLower(filepath.Ext(p))] && !seen[p] {
+			seen[p] = true
+			out = append(out, p)
+		}
+	}
+	for _, root := range roots {
+		fi, err := os.Stat(root)
+		if err != nil {
+			return nil, err
+		}
+		if !fi.IsDir() {
+			add(root)
+			continue
+		}
+		err = filepath.WalkDir(root, func(p string, d os.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+			if d.IsDir() {
+				if !recursive && p != root {
+					return filepath.SkipDir
+				}
+				return nil
+			}
+			add(p)
+			return nil
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+	sort.Strings(out)
+	return out, nil
+}
+
+// look returns the first bare name found on PATH, or the first candidate that
+// is an existing path. Returns "" if none resolve.
+func look(candidates ...string) string {
+	for _, c := range candidates {
+		if strings.ContainsRune(c, filepath.Separator) {
+			if fi, err := os.Stat(c); err == nil && !fi.IsDir() {
+				return c
+			}
+			continue
+		}
+		if p, err := exec.LookPath(c); err == nil {
+			return p
+		}
+	}
+	return ""
+}

internal/assets/helpers_test.go

@@ -0,0 +1,63 @@
+package assets
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestWalk(t *testing.T) {
+	root := t.TempDir()
+	must := func(rel string) {
+		p := filepath.Join(root, rel)
+		if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(p, []byte("x"), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	must("a.MDL")
+	must("sub/b.mdl")
+	must("sub/c.txt")
+
+	exts := map[string]bool{".mdl": true}
+	got, err := walk([]string{root}, exts, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 2 {
+		t.Fatalf("recursive walk = %v, want 2 mdl files", got)
+	}
+
+	got, _ = walk([]string{root}, exts, false)
+	if len(got) != 1 || filepath.Base(got[0]) != "a.MDL" {
+		t.Fatalf("non-recursive walk = %v, want only a.MDL", got)
+	}
+
+	// A file argument that matches is included directly.
+	got, _ = walk([]string{filepath.Join(root, "sub", "b.mdl")}, exts, true)
+	if len(got) != 1 {
+		t.Fatalf("file arg walk = %v, want the file itself", got)
+	}
+}
+
+func TestLook(t *testing.T) {
+	dir := t.TempDir()
+	stub := filepath.Join(dir, "mytool")
+	if err := os.WriteFile(stub, []byte("#!/bin/sh\n"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv("PATH", dir)
+
+	if got := look("nope-not-here", "mytool"); got == "" {
+		t.Fatal("look should find mytool on PATH")
+	}
+	// Explicit existing path candidate.
+	if got := look(stub); got != stub {
+		t.Fatalf("look(%q) = %q, want the path itself", stub, got)
+	}
+	if got := look("definitely-absent-binary-xyz"); got != "" {
+		t.Fatalf("look = %q, want empty", got)
+	}
+}

internal/assets/mdl/mdl.go

@@ -0,0 +1,218 @@
+// Package mdl ports the ASCII MDL model-name checks from sow-assets-manifest's
+// mdl-name-lib.sh + mdl-scan.awk to pure Go. Binary (compiled) MDLs are opaque
+// here; the NWN engine is the validator for those. Detection mirrors
+// mdl-scan.awk exactly so behavior does not drift while that awk still runs in
+// sow-assets-manifest.
+package mdl
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// Mismatch is one model-name problem. Line is 1-based; 0 means the geometry
+// base-node mismatch, which the source has no single line for.
+type Mismatch struct {
+	Line int
+	What string
+	Got  string
+}
+
+// ExpectedName is the file stem with a trailing ".mdl" (any case) removed.
+func ExpectedName(path string) string {
+	base := filepath.Base(path)
+	if len(base) >= 4 && strings.EqualFold(base[len(base)-4:], ".mdl") {
+		return base[:len(base)-4]
+	}
+	return base
+}
+
+// ExpectedNameStem is an alias of ExpectedName kept for call-site clarity where
+// the value is used as the engine's model stem argument.
+func ExpectedNameStem(path string) string { return ExpectedName(path) }
+
+// IsASCII reports whether path is an uncompiled ASCII model: no NUL in the
+// first 256 bytes, and a leading keyword of '#' / newmodel / node /
+// setsupermodel. Mirrors mdl_is_ascii.
+func IsASCII(path string) (bool, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return false, err
+	}
+	return isASCII(data), nil
+}
+
+func isASCII(data []byte) bool {
+	head := data
+	if len(head) > 256 {
+		head = head[:256]
+	}
+	if bytes.IndexByte(head, 0) >= 0 {
+		return false
+	}
+	line := head
+	if i := bytes.IndexByte(line, '\n'); i >= 0 {
+		line = line[:i]
+	}
+	trimmed := strings.TrimLeft(string(line), " \t\r")
+	if strings.HasPrefix(trimmed, "#") {
+		return true
+	}
+	fields := strings.Fields(trimmed)
+	if len(fields) == 0 {
+		return false
+	}
+	tok := strings.ToLower(fields[0])
+	return strings.HasPrefix(tok, "newmodel") ||
+		strings.HasPrefix(tok, "node") ||
+		strings.HasPrefix(tok, "setsupermodel")
+}
+
+// lineFields splits a line into whitespace-delimited tokens with the trailing
+// CR removed, matching awk's default field split + \r strip.
+func lineFields(line string) []string {
+	return strings.Fields(strings.TrimRight(line, "\r"))
+}
+
+// field returns the 1-based nth field or "" if absent.
+func field(f []string, n int) string {
+	if n >= 1 && n <= len(f) {
+		return f[n-1]
+	}
+	return ""
+}
+
+// CheckNames returns every model-name mismatch in an ASCII model. Returns nil
+// for a binary model or one with no newmodel line (not a real model).
+func CheckNames(path string) ([]Mismatch, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	if !isASCII(data) {
+		return nil, nil
+	}
+	return checkNames(data, ExpectedName(path)), nil
+}
+
+func checkNames(data []byte, expected string) []Mismatch {
+	expLower := strings.ToLower(expected)
+	var out []Mismatch
+	seenModel := false
+	inGeom := false
+	curNode := ""
+	base := ""
+	baseFound := false
+
+	// header records one header-token mismatch (field n, 1-based) if the token
+	// is present and differs case-insensitively from the stem.
+	lines := strings.Split(string(data), "\n")
+	for i, raw := range lines {
+		f := lineFields(raw)
+		if len(f) == 0 {
+			continue
+		}
+		key := strings.ToLower(f[0])
+		mis := func(what string, n int) {
+			got := field(f, n)
+			if got != "" && !strings.EqualFold(got, expected) {
+				out = append(out, Mismatch{Line: i + 1, What: what, Got: got})
+			}
+		}
+		switch key {
+		case "newmodel":
+			seenModel = true
+			mis("newmodel", 2)
+		case "setsupermodel":
+			mis("setsupermodel model", 2)
+		case "beginmodelgeom":
+			inGeom = true
+			mis("beginmodelgeom", 2)
+		case "endmodelgeom":
+			inGeom = false
+			mis("endmodelgeom", 2)
+		case "donemodel":
+			mis("donemodel", 2)
+		case "newanim":
+			mis("newanim model", 3)
+		case "doneanim":
+			mis("doneanim model", 3)
+		case "node":
+			if inGeom {
+				curNode = field(f, 3)
+			}
+		case "parent":
+			if inGeom && !baseFound && strings.EqualFold(field(f, 2), "null") {
+				base = curNode
+				baseFound = true
+			}
+		}
+	}
+	if !seenModel {
+		return nil
+	}
+	if baseFound && base != "" && !strings.EqualFold(base, expLower) {
+		out = append(out, Mismatch{Line: 0, What: "root node", Got: base})
+	}
+	return out
+}
+
+// FixNames rewrites only the model identity to expected: the header tokens plus
+// the geometry base node's declaration / any parent / animroot pointing at the
+// old base name. Animation bone names and supermodel animroots are left alone
+// so inheritance keeps working. Mirrors mdl_fix_model_name in intent.
+//
+// ponytail: a rewritten line is rebuilt joining fields with single spaces and
+// drops a trailing CR, exactly like the awk it replaces; unchanged lines are
+// byte-identical. The engine ignores identity-line whitespace, and FixNames'
+// contract is only "produces a model that passes CheckNames", not byte parity.
+func FixNames(in []byte, expected string) (out []byte, changed bool) {
+	if !isASCII(in) {
+		return in, false
+	}
+	// oldbase: the base-node name to rename, only if it differs from expected.
+	oldbase := ""
+	for _, m := range checkNames(in, expected) {
+		if m.What == "root node" {
+			oldbase = m.Got
+		}
+	}
+
+	lines := strings.Split(string(in), "\n")
+	for idx, raw := range lines {
+		f := lineFields(raw)
+		if len(f) == 0 {
+			continue
+		}
+		key := strings.ToLower(f[0])
+		set := func(n int) bool {
+			if field(f, n) == "" {
+				return false
+			}
+			f[n-1] = expected
+			return true
+		}
+		modified := false
+		switch key {
+		case "newmodel", "setsupermodel", "beginmodelgeom", "endmodelgeom", "donemodel":
+			modified = set(2)
+		case "newanim", "doneanim":
+			modified = set(3)
+		case "node":
+			if oldbase != "" && strings.EqualFold(field(f, 3), oldbase) {
+				modified = set(3)
+			}
+		case "parent", "animroot":
+			if oldbase != "" && strings.EqualFold(field(f, 2), oldbase) {
+				modified = set(2)
+			}
+		}
+		if modified {
+			lines[idx] = strings.Join(f, " ")
+		}
+	}
+	out = []byte(strings.Join(lines, "\n"))
+	return out, !bytes.Equal(out, in)
+}

internal/assets/mdl/mdl_test.go

@@ -0,0 +1,114 @@
+package mdl
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func writeMDL(t *testing.T, name, body string) string {
+	t.Helper()
+	p := filepath.Join(t.TempDir(), name)
+	if err := os.WriteFile(p, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
+
+func TestIsASCII(t *testing.T) {
+	ascii := writeMDL(t, "foo.mdl", "newmodel foo\nbeginmodelgeom foo\n")
+	if ok, err := IsASCII(ascii); err != nil || !ok {
+		t.Fatalf("ascii: ok=%v err=%v, want true nil", ok, err)
+	}
+	bin := writeMDL(t, "bar.mdl", "\x00\x01binary\x00garbage")
+	if ok, err := IsASCII(bin); err != nil || ok {
+		t.Fatalf("binary: ok=%v err=%v, want false nil", ok, err)
+	}
+	hash := writeMDL(t, "baz.mdl", "# a comment\nnewmodel baz\n")
+	if ok, _ := IsASCII(hash); !ok {
+		t.Fatal("leading # should be ascii")
+	}
+}
+
+func TestExpectedName(t *testing.T) {
+	for in, want := range map[string]string{
+		"a/b/Foo.MDL":     "Foo",
+		"waxbt_b_091.mdl": "waxbt_b_091",
+		"x.mdl":           "x",
+	} {
+		if got := ExpectedName(in); got != want {
+			t.Errorf("ExpectedName(%q)=%q want %q", in, got, want)
+		}
+	}
+}
+
+func TestCheckNames(t *testing.T) {
+	// Header token mismatch + base-node mismatch in one file.
+	body := "newmodel wrong\n" +
+		"setsupermodel wrong a_base\n" +
+		"beginmodelgeom foo\n" +
+		"  node dummy Wmgst_m_081\n" +
+		"    parent null\n" +
+		"  endnode\n" +
+		"endmodelgeom foo\n" +
+		"donemodel foo\n"
+	p := writeMDL(t, "foo.mdl", body)
+	got, err := CheckNames(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Expected stem "foo": newmodel(wrong), setsupermodel(wrong), base node(Wmgst_m_081).
+	if len(got) != 3 {
+		t.Fatalf("got %d mismatches, want 3: %+v", len(got), got)
+	}
+	if got[0].What != "newmodel" || got[0].Got != "wrong" || got[0].Line != 1 {
+		t.Errorf("first mismatch = %+v", got[0])
+	}
+	base := got[len(got)-1]
+	if base.What != "root node" || base.Got != "Wmgst_m_081" || base.Line != 0 {
+		t.Errorf("base mismatch = %+v", base)
+	}
+
+	// Clean model -> no mismatches.
+	clean := writeMDL(t, "bar.mdl",
+		"newmodel bar\nbeginmodelgeom bar\n  node dummy bar\n    parent null\n  endnode\nendmodelgeom bar\ndonemodel bar\n")
+	if got, _ := CheckNames(clean); len(got) != 0 {
+		t.Fatalf("clean model reported mismatches: %+v", got)
+	}
+
+	// Binary model -> nil, no error.
+	bin := writeMDL(t, "b.mdl", "\x00\x00binary")
+	if got, _ := CheckNames(bin); got != nil {
+		t.Fatalf("binary reported mismatches: %+v", got)
+	}
+}
+
+func TestFixNamesRoundTrips(t *testing.T) {
+	body := "newmodel wrong\n" +
+		"setsupermodel wrong\n" +
+		"beginmodelgeom wrong\n" +
+		"  node dummy Wmgst_m_081\n" +
+		"    parent null\n" +
+		"  endnode\n" +
+		"endmodelgeom wrong\n" +
+		"donemodel wrong\n"
+	out, changed := FixNames([]byte(body), "foo")
+	if !changed {
+		t.Fatal("expected changed=true")
+	}
+	p := filepath.Join(t.TempDir(), "foo.mdl")
+	if err := os.WriteFile(p, out, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	got, err := CheckNames(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 0 {
+		t.Fatalf("fixed model still has mismatches: %+v\n%s", got, out)
+	}
+	// Idempotent: fixing a clean model changes nothing.
+	if _, changed := FixNames(out, "foo"); changed {
+		t.Fatal("second fix reported a change")
+	}
+}

internal/assets/run.go

@@ -0,0 +1,55 @@
+package assets
+
+import (
+	"fmt"
+	"io"
+)
+
+const (
+	exitOK    = 0
+	exitFail  = 1  // problems found / per-file failures
+	exitUsage = 64 // bad invocation / unknown subcommand / bad flags
+	exitTool  = 70 // missing external tool / internal error
+)
+
+// Run executes an assets subcommand. args[0] is the subcommand; returns the
+// process exit code.
+func Run(args []string, stdout, stderr io.Writer, getenv func(string) string) int {
+	if len(args) == 0 {
+		printUsage(stderr)
+		return exitUsage
+	}
+	rest := args[1:]
+	switch args[0] {
+	case "check-dupes":
+		return runCheckDupes(rest, stdout, stderr)
+	case "clean-dupes":
+		return runCleanDupes(rest, stdout, stderr)
+	case "check-mdl":
+		return runCheckMDL(rest, stdout, stderr)
+	case "fix-mdl":
+		return runFixMDL(rest, stdout, stderr)
+	case "convert":
+		return runConvert(rest, stdout, stderr)
+	case "upscale":
+		return runUpscale(rest, stdout, stderr)
+	case "compile":
+		return runCompile(rest, stdout, stderr, getenv)
+	default:
+		fmt.Fprintf(stderr, "assets: unknown subcommand %q\n\n", args[0])
+		printUsage(stderr)
+		return exitUsage
+	}
+}
+
+func printUsage(w io.Writer) {
+	fmt.Fprint(w, `usage:
+  assets compile      [--nwn INSTALL] [--non-recursive] <dir>...
+  assets convert      [--to dds|png|tga] [--backend PATH] [--non-recursive] <dir>...
+  assets upscale      [--scale N] [--backend PATH] [--non-recursive] <dir>...
+  assets check-mdl    <path>...
+  assets fix-mdl      [--dry-run] <path>...
+  assets check-dupes  <dir>...
+  assets clean-dupes  [--dry-run] <primary> <clean>
+`)
+}

internal/assets/run_test.go

@@ -0,0 +1,26 @@
+package assets
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func env(string) string { return "" }
+
+func TestRunNoArgsIsUsage(t *testing.T) {
+	var out, errw bytes.Buffer
+	if code := Run(nil, &out, &errw, env); code != exitUsage {
+		t.Fatalf("no args exit = %d, want %d", code, exitUsage)
+	}
+	if !strings.Contains(errw.String(), "usage") {
+		t.Fatalf("no args should print usage, got: %q", errw.String())
+	}
+}
+
+func TestRunUnknownSubcommandIsUsage(t *testing.T) {
+	var out, errw bytes.Buffer
+	if code := Run([]string{"frobnicate"}, &out, &errw, env); code != exitUsage {
+		t.Fatalf("unknown subcommand exit = %d, want %d", code, exitUsage)
+	}
+}

internal/assets/upscale.go

@@ -0,0 +1,98 @@
+package assets
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+var upscaleBackends = []string{"upscayl-bin", "upscayl", "realesrgan-ncnn-vulkan", "waifu2x-ncnn-vulkan"}
+
+// runUpscale upscales textures in place through an installed ncnn-vulkan
+// backend. DDS inputs are bridged through PNG so the NWN flip stays correct.
+func runUpscale(args []string, stdout, stderr io.Writer) int {
+	fs := flag.NewFlagSet("upscale", flag.ContinueOnError)
+	fs.SetOutput(stderr)
+	scale := fs.Int("scale", 4, "upscale factor")
+	backend := fs.String("backend", "", "override the upscaler binary")
+	nonRecursive := fs.Bool("non-recursive", false, "do not descend into subdirectories")
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+	dirs := fs.Args()
+	if len(dirs) == 0 {
+		fmt.Fprintln(stderr, "assets upscale: usage: upscale [--scale N] <dir>...")
+		return exitUsage
+	}
+
+	candidates := upscaleBackends
+	if *backend != "" {
+		candidates = []string{*backend}
+	}
+	tool := look(candidates...)
+	if tool == "" {
+		fmt.Fprintf(stderr, "assets upscale: no upscaler found — install one of: %s\n", strings.Join(upscaleBackends, ", "))
+		return exitTool
+	}
+
+	files, err := walk(dirs, textureExts, !*nonRecursive)
+	if err != nil {
+		fmt.Fprintln(stderr, "assets upscale:", err)
+		return exitUsage
+	}
+
+	// magick is only needed if a .dds input is present; resolve lazily.
+	magick := ""
+	failed := false
+	for _, src := range files {
+		var upErr error
+		if strings.EqualFold(filepath.Ext(src), ".dds") {
+			if magick == "" {
+				if magick = look("magick"); magick == "" {
+					fmt.Fprintln(stderr, "assets upscale: .dds input needs ImageMagick (magick) for the png bridge")
+					return exitTool
+				}
+			}
+			upErr = upscaleDDS(tool, magick, src, *scale)
+		} else {
+			upErr = upscaleImage(tool, src, src, *scale)
+		}
+		if upErr != nil {
+			fmt.Fprintf(stderr, "assets upscale: %s: %v\n", src, upErr)
+			failed = true
+		}
+	}
+	if failed {
+		return exitFail
+	}
+	return exitOK
+}
+
+// upscaleImage runs the ncnn-vulkan backend to upscale src into dst (may be the
+// same path).
+func upscaleImage(tool, src, dst string, scale int) error {
+	tmp := dst + ".upscaled.png"
+	out, err := runner("", nil, tool, "-i", src, "-o", tmp, "-s", strconv.Itoa(scale))
+	if err != nil {
+		return fmt.Errorf("%s: %v: %s", filepath.Base(tool), err, strings.TrimSpace(string(out)))
+	}
+	return os.Rename(tmp, dst)
+}
+
+// upscaleDDS bridges a DDS through PNG: dds->png (flip), upscale, png->dds
+// (flip back), yielding a correctly-flipped upscaled DDS.
+func upscaleDDS(tool, magick, src string, scale int) error {
+	tmpPNG := src + ".bridge.png"
+	if err := ddsToPNG(magick, src, tmpPNG); err != nil {
+		return err
+	}
+	defer os.Remove(tmpPNG)
+	if err := upscaleImage(tool, tmpPNG, tmpPNG, scale); err != nil {
+		return err
+	}
+	return pngToDDS(magick, tmpPNG, src)
+}

internal/assets/upscale_test.go

@@ -0,0 +1,69 @@
+package assets
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestUpscalePNGUsesBackend(t *testing.T) {
+	// A fake backend binary on PATH so look() resolves it.
+	binDir := t.TempDir()
+	fake := filepath.Join(binDir, "upscayl-bin")
+	if err := os.WriteFile(fake, []byte("#!/bin/sh\n"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv("PATH", binDir)
+
+	// Stub runner: emulate `-i in -o out -s scale` by copying in->out.
+	orig := runner
+	defer func() { runner = orig }()
+	var gotScale string
+	runner = func(dir string, env []string, name string, args ...string) ([]byte, error) {
+		var in, out string
+		for i := 0; i < len(args)-1; i++ {
+			switch args[i] {
+			case "-i":
+				in = args[i+1]
+			case "-o":
+				out = args[i+1]
+			case "-s":
+				gotScale = args[i+1]
+			}
+		}
+		data, err := os.ReadFile(in)
+		if err != nil {
+			return nil, err
+		}
+		return nil, os.WriteFile(out, data, 0o644)
+	}
+
+	dir := t.TempDir()
+	src := filepath.Join(dir, "tex.png")
+	if err := os.WriteFile(src, []byte("pngdata"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	var stdout, stderr bytes.Buffer
+	if code := runUpscale([]string{"--scale", "2", dir}, &stdout, &stderr); code != exitOK {
+		t.Fatalf("upscale exit = %d\n%s", code, stderr.String())
+	}
+	if gotScale != "2" {
+		t.Fatalf("scale passed to backend = %q, want 2", gotScale)
+	}
+	if data, _ := os.ReadFile(src); string(data) != "pngdata" {
+		t.Fatalf("upscaled file content = %q, want the backend output", data)
+	}
+}
+
+func TestUpscaleNoBackendFailsClosed(t *testing.T) {
+	t.Setenv("PATH", t.TempDir()) // empty PATH: no backend resolvable
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "tex.png"), []byte("x"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	var stdout, stderr bytes.Buffer
+	if code := runUpscale([]string{dir}, &stdout, &stderr); code != exitTool {
+		t.Fatalf("no-backend exit = %d, want %d", code, exitTool)
+	}
+}

internal/dispatch/dispatch.go

@@ -17,6 +17,7 @@ import (
 	"os"
 
 	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/app"
+	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/assets"
 	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/buildinfo"
 	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/depot"
 	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/menu"
@@ -103,6 +104,21 @@ var Registry = []Builder{
 		},
 		Wired: true,
 	},
+	{
+		Name:    "assets",
+		Bin:     "crucible-assets",
+		Summary: "compile/convert/upscale NWN assets + mdl/dupe integrity",
+		Commands: []Command{
+			{Name: "compile", Summary: "compile ASCII .mdl models to binary in place", Usage: "crucible assets compile [--nwn INSTALL] [--non-recursive] <dir>..."},
+			{Name: "convert", Summary: "convert textures to/from NWN DDS (flips vertically)", Usage: "crucible assets convert [--to dds|png|tga] [--backend PATH] [--non-recursive] <dir>..."},
+			{Name: "upscale", Summary: "upscale textures through an installed backend", Usage: "crucible assets upscale [--scale N] [--backend PATH] [--non-recursive] <dir>..."},
+			{Name: "check-mdl", Summary: "report uncompiled ASCII .mdl and model-name mismatches", Usage: "crucible assets check-mdl <path>..."},
+			{Name: "fix-mdl", Summary: "lowercase .mdl names and rewrite model identity to match", Usage: "crucible assets fix-mdl [--dry-run] <path>..."},
+			{Name: "check-dupes", Summary: "report runtime-name (basename) collisions across dirs", Usage: "crucible assets check-dupes <dir>..."},
+			{Name: "clean-dupes", Summary: "delete clean-tree files whose basename collides with primary", Usage: "crucible assets clean-dupes [--dry-run] <primary> <clean>"},
+		},
+		Wired: true,
+	},
 	{
 		Name:    "hak",
 		Bin:     "crucible-hak",
@@ -375,11 +391,16 @@ func runBuilder(name string, args []string, out, errw io.Writer) int {
 			return exitOK
 		}
 	}
-	if b.Name == "depot" && b.Wired {
-		// depot parses its own subcommand (status/push/verify/get/pull) and
-		// has its own richer exit contract (0/1/2/64/70), so it bypasses the
-		// b.Commands/delegateLegacy routing entirely.
-		return depot.Run(args, out, errw, os.Getenv)
+	if b.Wired {
+		// depot and assets are self-contained builders: they parse their own
+		// subcommands and own their exit contract, bypassing the
+		// b.Commands/delegateLegacy legacy routing entirely.
+		switch b.Name {
+		case "depot":
+			return depot.Run(args, out, errw, os.Getenv)
+		case "assets":
+			return assets.Run(args, out, errw, os.Getenv)
+		}
 	}
 	if !b.Wired {
 		// No migrated logic yet (depot): fail closed, never fake an artifact.

internal/dispatch/dispatch_test.go

@@ -151,6 +151,7 @@ func TestBuilderHelpIsOK(t *testing.T) {
 func TestCanonicalCommandSurface(t *testing.T) {
 	want := map[string][]string{
 		"depot":   {"status", "push", "verify", "get", "pull"},
+		"assets":  {"compile", "convert", "upscale", "check-mdl", "fix-mdl", "check-dupes", "clean-dupes"},
 		"hak":     {"build", "manifest"},
 		"module":  {"build", "extract", "validate", "compare", "manifest"},
 		"topdata": {"validate", "build", "package", "compare", "convert"},
@@ -172,10 +173,10 @@ func TestRegistryCommandNamesAndAliasesAreUnambiguous(t *testing.T) {
 	for _, builder := range Registry {
 		seen := map[string]bool{}
 		for _, command := range builder.Commands {
-			// depot parses its own subcommands and bypasses AppCommand routing
-			// entirely (see the depot special-case in runBuilder), so its
-			// Commands carry no AppCommand.
-			requireAppCommand := builder.Name != "depot"
+			// depot and assets parse their own subcommands and bypass AppCommand
+			// routing entirely (see the self-contained-builder branch in
+			// runBuilder), so their Commands carry no AppCommand.
+			requireAppCommand := builder.Name != "depot" && builder.Name != "assets"
 			if command.Name == "" || command.Summary == "" || command.Usage == "" || (requireAppCommand && command.AppCommand == "") {
 				t.Errorf("%s has incomplete command metadata: %#v", builder.Name, command)
 			}

scripts/crucible-smoke.sh

@@ -18,7 +18,7 @@ bin=bin
 
 # Keep in sync with internal/dispatch.Registry (Wired flag).
 unwired=()
-wired=(depot hak module topdata wiki)
+wired=(assets depot hak module topdata wiki)
 
 exit_of() { set +e; "$@" >/dev/null 2>&1; local c=$?; set -e; echo "${c}"; }