Ship the measured Meta Content Seal cohort with auto routing and --vendor override

Full Meta Muse Image support in the invisible-removal path:

- QWEN_ZIMAGE_META_STRENGTH = 0.1: derived by the standard
  worst-boundary-plus-cross-source-spread method over five oracle-bracketed
  generations (data/contentseal/manifest.csv)
- Auto mode: vendor_for_strength routes a file whose only provenance is the
  standalone AI IPTC trainedAlgorithmicMedia tag onto the meta cohort; C2PA
  issuers win first, so Google/OpenAI/Microsoft routing is unchanged. Muse
  WebP outputs place the XMP in a tail chunk, so the scan uses the shared
  chunk-aware metadata.scan_head rather than a plain head read
- Explicit override: --vendor on invisible/all/batch and
  InvisibleOptions.vendor name the cohort on stripped files; naming a cohort
  asserts the watermark is present, so the no-signal gate treats it like
  --force at both the CLI and API seams
- sdxl-zimage has no measured Meta rung: an explicit meta vendor falls to
  the conservative unknown 0.25 rather than inventing one
- identify emits a Content Seal caveat pointing at the removal path
- The legacy visible 'Imagined with AI' mark stays unregistered: a dedicated
  sample hunt (newsroom mockups, community posts, press screenshots, dead
  imagine.meta.com, broken Wayback captures) found no pixel-verifiable
  capture, and the registry rule forbids encoding a corner without one.
  erase --region remains its removal path; outcome recorded in the landscape

Co-Authored-By: Claude Fable 4.5 <noreply@anthropic.com>

docs/cli.md

@@ -387,6 +387,23 @@ detected. Use `--force` when you know the image should be processed:
 remove-ai-watermarks invisible image.png -o clean.png --force
 ```
 
+### Choose a strength cohort
+
+`--vendor` selects the cohort the default strength resolves from. `auto`
+(the default) derives it from provenance: the C2PA issuer for
+OpenAI/Google/Microsoft, and the standalone AI IPTC tag for Meta Content Seal
+(Muse output carries no C2PA; the tag is a standard code, so C2PA evidence
+always wins first). An explicit value both names the cohort for stripped files
+and implies the scrub runs -- naming the cohort asserts the pixel watermark is
+present -- exactly like `--force` plus a measured floor:
+
+```bash
+remove-ai-watermarks invisible muse_output.webp -o clean.png --vendor meta
+```
+
+The same option exists on `all` and `batch`, and as
+`InvisibleOptions(vendor="meta")` in the Python API.
+
 ### Choose a pipeline
 
 | Pipeline | When to use it |

docs/module-internals.md

@@ -1170,18 +1170,22 @@ unreachable constant would be dead code.
 Full spread: worst first-clean boundary (0.0525, 0.06] on lighthouse, easiest
 source already clean at 0.015. Following the same derivation as the OpenAI and
 Microsoft floors (worst clean boundary plus one full observed cross-source
-spread): 0.06 + (0.0525 - 0.015) = 0.0975, rounded up to **0.1**. This is a
-candidate `meta` floor, not yet a shipped constant: Muse outputs carry no C2PA,
-so `vendor_for_strength` has no signal that could route them onto the flat
-vendor map automatically. Encoding 0.1 as `QWEN_ZIMAGE_META_STRENGTH` makes
-sense only once the tool gains an explicit way to opt into a Meta cohort (for
-example a CLI `--vendor meta` override); the default resolution-adaptive curve
-(~0.1305 at 2.56 MP) already clears every measured source, so default behavior
-needs no change. Oracle verdicts carry a per-generation ID and creation timestamp
-embedded in the watermark payload; both survived the 512 px resize and JPEG q85
-rows, so payload recovery outlives the detection threshold. Oracle session
-limits are per-IP, server-side, and sliding-window: clearing cookies and storage
-does not reset them, and a burst exhausts the window minutes after it reopens.
+spread): 0.06 + (0.0525 - 0.015) = 0.0975, rounded up to **0.1**. Shipped as
+`QWEN_ZIMAGE_META_STRENGTH` with two routing paths: auto mode routes a file
+whose only provenance is the standalone AI IPTC tag onto the cohort
+(`vendor_for_strength` checks C2PA issuers first, so Google/OpenAI/Microsoft
+evidence always wins, and the tag's other users ship no invisible watermark
+this profile targets), and `--vendor meta` / `InvisibleOptions.vendor` names the
+cohort explicitly on stripped files, implying the scrub runs (naming the cohort
+asserts the watermark is present). sdxl-zimage has no measured Meta rung and an
+explicit meta vendor there falls to the conservative unknown 0.25. The default
+resolution-adaptive curve (~0.1305 at 2.56 MP) also clears every measured
+source, so default behavior needed no change. Oracle verdicts carry a
+generation ID and creation timestamp embedded in the watermark payload; both
+survived the 512 px resize and JPEG q85 rows, so payload recovery outlives the
+detection threshold. Oracle session limits are per-IP, server-side, and
+sliding-window: clearing cookies and storage does not reset them, and a burst
+exhausts the window minutes after it reopens.
 
 ### Static prompt embeddings
 

docs/python-api.md

@@ -112,6 +112,18 @@ raiw.remove_all(
 )
 ```
 
+`vendor="meta"` names a strength cohort explicitly (the measured Content Seal
+floor) for a stripped file whose provenance no longer carries the AI IPTC tag,
+and implies the scrub runs:
+
+```python
+raiw.remove_all(
+    "muse_output.webp",
+    "clean.png",
+    invisible=InvisibleOptions(vendor="meta"),
+)
+```
+
 `InvisibleOptions` carries only what `InvisibleEngine` itself takes, and uses the
 engine's own parameter names and defaults. `force`, which decides whether the
 engine runs at all, is a parameter of `remove_all` and `remove_batch` alongside

docs/supported-signals.md

@@ -172,9 +172,15 @@ documentation never mentions the seal. The
 default `qwen-zimage` profile clears Content Seal at the default
 resolution-adaptive strength (oracle-verified on 2.56 MP generations); measured
 strength boundaries are recorded in `data/contentseal/manifest.csv` and
-[module internals](module-internals.md#meta-content-seal-boundaries-for-qwen-zimage)
-(derived Meta floor 0.1 by the standard spread method, not shipped as a constant
-because no provenance signal can route Muse output onto a vendor cohort).
+[module internals](module-internals.md#meta-content-seal-boundaries-for-qwen-zimage).
+The derived Meta floor (0.1 by the standard spread method) ships as a measured
+cohort: auto mode routes a file whose only provenance is the standalone AI IPTC
+tag to it (the tag is not Meta-exclusive; other tag users ship no invisible
+watermark this profile targets, and Google/OpenAI/Microsoft C2PA evidence
+always wins first), and `invisible --vendor meta` (also `all` and `batch`, and
+`InvisibleOptions.vendor` in the API) names the cohort explicitly on stripped
+files. An explicit vendor implies the scrub runs: naming the cohort asserts the
+pixel watermark is present.
 The seal survives resizing, JPEG recompression, and metadata stripping; it dies
 to center crops of a third to a half, matching the Reuters 2026-07-11 finding
 that Meta's detector missed 55% of cropped Muse images.

docs/watermarking-landscape.md

@@ -161,9 +161,9 @@ Two consequences we can exploit: (1) the 5% floor is a **scale prior** -- a comp
 
 **Tencent Yuanbao: RESOLVED 2026-07-25, registered (`yuanbao_engine.py`).** The standard mark is a compact two-line italic `元宝` over `AI生成` block at bottom-right. It switches between light and dark strokes with the scene, so detection uses polarity-independent local contrast rather than a white top-hat. The separate one-line overlay variant remains evidence-limited to one example.
 
-**Meta Muse Image / Content Seal: current state VERIFIED 2026-08-26 against live artifacts.** Muse Image (launched 2026-07-07, first image model from Meta Superintelligence Labs) puts no visible mark on output. Every output carries Content Seal, a proprietary invisible pixel watermark; research lineage is open (`github.com/facebookresearch/content-seal`, Pixel Seal / VideoSeal / Watermark Anything), but the deployed implementation is proprietary and unpublished. API outputs and Meta CDN copies also carry XMP `iptcExt:DigitalSourceType = trainedAlgorithmicMedia` (a standard IPTC code, not Meta-exclusive). The only reader is the anonymous web oracle `meta.ai/identification`, which returns model attribution plus a per-generation ID and timestamp embedded in the payload. Verified robustness (our corpus, `data/contentseal/`): seal survives CDN WebP transcode, 512 px resize, JPEG q85, and full metadata stripping; it is lost to center crops of 33-50% linear size (Reuters measured 55% detector misses on cropped images, 2026-07-11). The default `qwen-zimage` profile clears it (oracle-verified). Legacy paragraph retained below.
+**Meta Muse Image / Content Seal: current state VERIFIED 2026-08-26 against live artifacts.** Muse Image (launched 2026-07-07, first image model from Meta Superintelligence Labs) puts no visible mark on output. Every output carries Content Seal, a proprietary invisible pixel watermark; research lineage is open (`github.com/facebookresearch/content-seal`, Pixel Seal / VideoSeal / Watermark Anything), but the deployed implementation is proprietary and unpublished. API outputs and Meta CDN copies also carry XMP `iptcExt:DigitalSourceType = trainedAlgorithmicMedia` (a standard IPTC code, not Meta-exclusive). The only reader is the anonymous web oracle `meta.ai/identification`, which returns model attribution plus a per-generation ID and timestamp embedded in the payload. Verified robustness (our corpus, `data/contentseal/`): seal survives CDN WebP transcode, 512 px resize, JPEG q85, and full metadata stripping; it is lost to center crops of 33-50% linear size (Reuters measured 55% detector misses on cropped images, 2026-07-11). Removal is fully supported and oracle-verified on the default profile, with a measured Meta strength floor (0.1) shipped behind auto IPTC routing and an explicit `--vendor meta` override; see [supported signals](supported-signals.md) and [module internals](module-internals.md). Legacy paragraph retained below.
 
-**Meta `Imagined with AI` (string VERIFIED (a) from Meta's own newsroom; POSITION NOT VERIFIED).** Sources conflict on placement. Do not encode a corner without a verified sample. `identify` reads the supported IPTC disclosure; it does not decode Meta's proprietary invisible watermark. Source: `https://about.fb.com/news/2024/02/labeling-ai-generated-images-on-facebook-instagram-and-threads/`.
+**Meta `Imagined with AI` (string VERIFIED (a) from Meta's own newsroom; POSITION NOT VERIFIED).** Sources conflict on placement. Do not encode a corner without a verified sample. A dedicated 2026-08-27 sample hunt failed to obtain one: the Feb-2024 newsroom images are UI mockups whose photos carry no in-pixel mark; community posts (Threads `C8_rS_MuEId` titled "lower left corner", a Facebook share) corroborate bottom-LEFT verbally but their files defeat pixel verification; press screenshots predate the mark (Dec 2023); `imagine.meta.com` is dead (redirects to meta.ai) and its Wayback captures are broken SPA error pages. The mark's generator no longer exists (Muse output has no visible mark), so no fresh sample can be made. Removal stays on the generic `erase --region` path until a legacy capture surfaces. Source: `https://about.fb.com/news/2024/02/labeling-ai-generated-images-on-facebook-instagram-and-threads/`.
 
 **Samsung English/other locales: still not established.** Samsung's own support page says only that "A Galaxy AI watermark will appear on AI-generated images" -- no string, no corner. Every community thread carrying the exact English string returned HTTP 403 to WebFetch, so the search paraphrase (bottom-left) is deliberately NOT recorded as fact. Feature-tier detail (b): the mark is applied by Generative Edit / sketch-to-image but reportedly NOT by Object Eraser, so Samsung absence is feature-dependent. The four-star icon variant: nothing found.