imazen · lilith · May 6, 2026 · May 27, 2026 · May 27, 2026 · May 28, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -40,9 +40,11 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: crate
-      - run: cargo check
+      - run: cargo check --workspace
         working-directory: crate
-      - run: cargo clippy -- -D warnings
+      - run: cargo clippy --workspace --all-targets -- -D warnings
+        working-directory: crate
+      - run: cargo clippy -p corruption-corpus --all-targets --features driver -- -D warnings
         working-directory: crate
 
   test-unit:
@@ -68,7 +70,9 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: crate
-      - run: cargo test
+      - run: cargo test --workspace
+        working-directory: crate
+      - run: cargo test -p corruption-corpus --features driver
         working-directory: crate
 
   wasm:
@@ -91,30 +95,30 @@ jobs:
           echo "$HOME/.wasmtime/bin" >> $GITHUB_PATH
 
       - name: Check (scalar)
-        run: cargo check --target wasm32-wasip1
+        run: cargo check --workspace --target wasm32-wasip1
         working-directory: crate
 
       - name: Check (SIMD128)
         env:
           RUSTFLAGS: "-C target-feature=+simd128"
-        run: cargo check --target wasm32-wasip1
+        run: cargo check --workspace --target wasm32-wasip1
         working-directory: crate
 
       - name: Clippy (wasm32)
-        run: cargo clippy --target wasm32-wasip1 -- -D warnings
+        run: cargo clippy --workspace --target wasm32-wasip1 -- -D warnings
         working-directory: crate
 
       - name: Test (SIMD128)
         env:
           RUSTFLAGS: "-C target-feature=+simd128"
           CARGO_TARGET_WASM32_WASIP1_RUNNER: "wasmtime --dir ."
-        run: cargo test --lib --target wasm32-wasip1
+        run: cargo test --lib --workspace --target wasm32-wasip1
         working-directory: crate
 
       - name: Test (scalar)
         env:
           CARGO_TARGET_WASM32_WASIP1_RUNNER: "wasmtime --dir ."
-        run: cargo test --lib --target wasm32-wasip1
+        run: cargo test --lib --workspace --target wasm32-wasip1
         working-directory: crate
 
   test-integration:

diff --git a/.gitignore b/.gitignore
@@ -20,3 +20,9 @@ qoi-benchmark/.tmp_download/
 
 # wasm test temp directory (created by tests::wasm::test_read_only_cache)
 crate/.corpus-test-tmp/
+
+# Multi-agent coordination marker (never committed)
+.workongoing
+
+# Corruption-corpus driver output (generated PNGs/JPEGs)
+crate/corruption-out/
diff --git a/crate/CHANGELOG.md b/crate/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## [Unreleased]
+
+### Changed
+- Extracted the structural-corruption generator — which briefly lived here as the `corruptions` module + optional `driver` feature (never shipped in a tagged codec-corpus release) — into a new sibling workspace crate, [`corruption-corpus`](corruption-corpus/README.md), decoupling the corpus *fetcher* from the corruption *generator*. codec-corpus no longer depends on the `image` crate; the `driver` feature and the `corruption_corpus` example now live in `corruption-corpus`.
+
 ## [1.1.0] - 2026-04-14
 
 ### Added

diff --git a/crate/Cargo.lock b/crate/Cargo.lock
diff --git a/crate/Cargo.toml b/crate/Cargo.toml
@@ -1,4 +1,5 @@
 [workspace]
+members = ["corruption-corpus"]
 
 [package]
 name = "codec-corpus"

diff --git a/crate/README.md b/crate/README.md
@@ -255,6 +255,16 @@ let err = corpus.get("not-yet-cached").unwrap_err();
 
 Calling `get()` for an uncached dataset on WASM returns `Error::DownloadUnsupported` (not `NetworkUnavailable`). This is intentional — downloads must happen host-side.
 
+## Structural-corruption corpus
+
+The structural-corruption *generator* — a held-out falsification set for a
+perceptual metric's negative tail (channel swaps, dropped blocks, off-by-one
+edges, and seven more deterministic distortion families) — lives in the sibling
+**[`corruption-corpus`](corruption-corpus/)** workspace crate, decoupled from
+this fetcher. See its [README](corruption-corpus/README.md) for the family
+catalog, the `score(corruption) < score(q20-anchor)` gate, and the
+`corruption_corpus` generator example.
+
 ## Dependencies
 
 Four Rust crates, all small:

diff --git a/crate/corruption-corpus/.gitignore b/crate/corruption-corpus/.gitignore
@@ -0,0 +1,2 @@
+/target
+/corruption-out
diff --git a/crate/corruption-corpus/CHANGELOG.md b/crate/corruption-corpus/CHANGELOG.md
@@ -0,0 +1,21 @@
+# Changelog
+
+## [Unreleased]
+
+### Added
+- **Initial extraction** from `codec-corpus` — this crate was the
+  `codec_corpus::corruptions` module through codec-corpus 1.1.x, now split into
+  its own workspace member so the structural-corruption *generator* is decoupled
+  from the corpus *fetcher*. The module was self-contained (it depended only on
+  `image`, `serde`, and its own `prng`), so the split is a clean move; no logic
+  changed.
+- Structural-corruption distortion corpus: ten deterministic (SplitMix64-seeded,
+  dependency-free) distortion families parameterized by region size + severity,
+  plus a `ManifestEntry` schema and the `catalog()` / `manifest_for_reference()`
+  sweep generators. Pure RGB-buffer math; stays in the default build and
+  compiles to WASM.
+- **`driver` feature** (optional `image` dep): the `driver` module builds the
+  score-ready quad `(reference, corruption, q20-anchor, q10-anchor)` for the
+  metric gate `score(corruption) < score(q20)`, plus the `corruption_corpus`
+  example that emits images + `_MANIFEST.json` on demand (no corrupted bytes
+  committed).
diff --git a/crate/corruption-corpus/Cargo.toml b/crate/corruption-corpus/Cargo.toml
@@ -0,0 +1,40 @@
+[package]
+name = "corruption-corpus"
+version = "0.1.0"
+edition = "2024"
+description = "Deterministic structural-corruption image generator — a held-out falsification set for a perceptual metric's negative tail (channel swaps, dropped blocks, off-by-one edges, bit-flips, geometric, chroma-boundary, overlay, tone)"
+license = "Apache-2.0"
+repository = "https://github.com/imazen/codec-corpus"
+readme = "README.md"
+keywords = ["image", "corruption", "test-data", "perceptual", "metric"]
+categories = ["development-tools::testing", "multimedia::images"]
+rust-version = "1.85"
+
+[lib]
+name = "corruption_corpus"
+
+[dependencies]
+serde = { version = "1", features = ["derive"] }
+
+# `image` is only needed by the `driver` feature (loading reference images +
+# encoding/decoding JPEG anchors). The corruption generators themselves are pure
+# RGB-buffer math with no decode dependency, so they stay in the default build
+# and remain wasm-clean.
+image = { version = "0.25.10", optional = true, default-features = false, features = [
+    "png",
+    "jpeg",
+] }
+
+[dev-dependencies]
+serde_json = "1"
+
+[features]
+default = []
+# Enables the corruption `driver` module which loads reference PNGs and emits
+# JPEG q20/q10 honest-lq anchors via the `image` crate. Without it, only the
+# seeded in-memory generators + manifest types are available.
+driver = ["dep:image"]
+
+[[example]]
+name = "corruption_corpus"
+required-features = ["driver"]