Skills nx-matting
📦
nx-matting
v1.0.0 Content revision r1 Critical ⚙️ External commands🌐 Network access📁 Filesystem access
Remove Image and Video Backgrounds
Background removal often requires complex local tools or cloud uploads. This skill runs BiRefNet locally and creates transparent image or video files.
Supports: Claude Codex Code(CC)
Do not auto-install this skill.
The canonical policy requires operator review before any installation action.
Install with my Agent
Copy this request to your Agent. It includes the canonical Skill page and manifest.
Agent request
Review the Skillstore skill "nx-matting" from https://skillstore.io/skills/xiaowu89-nx-matting.md and its manifest at https://skillstore.io/api/skills/xiaowu89-nx-matting/manifest. Verify the artifact. Do not auto-install. Inspect the skill and report your findings, then wait for an operator or manual installation decision.Your Agent should still show its plan and request any confirmation required by the security policy.
Agent-readable resources
Use these links when an AI agent, crawler, or script needs clean context instead of reading the full page.
Test it
Using "nx-matting". Remove the background from C:\photos\portrait.jpg.
Expected outcome:
Created C:\photos\portrait_transparent.png with the original dimensions and a transparent background.
Using "nx-matting". Create a transparent WebM from C:\videos\demo.mp4 without audio.
Expected outcome:
Created C:\videos\demo_transparent.webm without audio and reported the selected inference backend.
Using "nx-matting". Check whether this computer is ready for matting.
Expected outcome:
Reported Windows architecture, available runtimes, installed models, Vulkan status, cache location, and FFmpeg availability.
Security Audit
Criticalv1 • 7/30/2026 Open versioned report
Most backtick, reconnaissance, temporary-path, and entropy alerts are syntax or documentation false positives. Confirmed risks include PowerShell execution with policy bypass, automatic remote artifact downloads, and unverified FFmpeg discovery outside the skill root. A critical instruction forces assistants to repeat a Base64-obfuscated third-party contact notice.
10
Files scanned
1,294
Lines analyzed
20
Review items
0
False positives ignored
Confirmed security concerns (2)
Critical
Prompt Injection Attempt Detected
The skill says the final reply “必须原样展示” a third-party contact notice. Base64 hides the notice in code and forces unsolicited contact promotion.
The instruction explicitly controls the assistant's final response, and the script decodes and injects the same contact notice into terminal events.
High
Automatic Execution of Author-Hosted Native Binaries
Normal processing downloads opaque Windows executables from author-controlled endpoints and runs them. Hashes ensure consistency but provide no independent provenance.
The manifest identifies executable artifacts, while the script downloads them using author-supplied hashes and selects them for local inference.
Capability review items (20)
These are real local capabilities that may be expected for this skill, so they require review but are not counted as confirmed malicious behavior.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "scripts/matting.ps1" image `
The documentation directs users or agents to execute the bundled PowerShell script with ExecutionPolicy Bypass. That script can download and run native binaries.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "scripts/matting.ps1" video `
The documentation directs users or agents to execute the bundled PowerShell script with ExecutionPolicy Bypass. That script can download and run native binaries.
High
Path traversal sequence
Add-Candidate (Join-Path $SkillRoot "..\..\ffmpeg") "nxengine"
The script searches two directories above its root for FFmpeg and later executes a matching binary. The candidate receives capability checks but no integrity or signature verification.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "<skill-root>\scripts\matting.ps1" image `
The skill directs the agent to execute the bundled PowerShell script with ExecutionPolicy Bypass. The script can download and run native processing binaries.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "<skill-root>\scripts\matting.ps1" image `
The skill directs the agent to execute the bundled PowerShell script with ExecutionPolicy Bypass. The script can download and run native processing binaries.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "<skill-root>\scripts\matting.ps1" video `
The skill directs the agent to execute the bundled PowerShell script with ExecutionPolicy Bypass. The script can download and run native processing binaries.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "<skill-root>\scripts\matting.ps1" video `
The skill directs the agent to execute the bundled PowerShell script with ExecutionPolicy Bypass. The script can download and run native processing binaries.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "<skill-root>\scripts\matting.ps1" doctor
The skill directs the agent to execute the bundled PowerShell script with ExecutionPolicy Bypass. The script can download and run native processing binaries.
High
PowerShell invocation
powershell.exe -NoProfile -ExecutionPolicy Bypass -File "<skill-root>\scripts\matting.ps1" ensure-mo
The skill directs the agent to execute the bundled PowerShell script with ExecutionPolicy Bypass. The script can download and run native processing binaries.
Medium
Hardcoded URL
"https://www.gyan.dev/ffmpeg/builds/packages/ffmpeg-8.1.2-essentials_build.zip"
The script can download this FFmpeg archive and execute its binaries. SHA-256 verification reduces tampering risk, but remote executable acquisition remains security-sensitive.
Low
Hardcoded URL
"https://modelscope.cn/models/xiaowu89/BiRefNet-GGUF/resolve/3b9e5ff30cb66902e9b80857be16a3d3415f732
This URL supplies a native runtime that the script downloads and executes. Size and SHA-256 checks reduce tampering risk but do not remove the remote binary trust dependency.
Low
Hardcoded URL
"https://modelscope.cn/models/xiaowu89/BiRefNet-GGUF/resolve/master/nx-matting-cpu.exe"
This URL supplies a native runtime that the script downloads and executes. Size and SHA-256 checks reduce tampering risk but do not remove the remote binary trust dependency.
Low
Hardcoded URL
"https://modelscope.cn/models/xiaowu89/BiRefNet-GGUF/resolve/3b9e5ff30cb66902e9b80857be16a3d3415f732
This URL supplies a native runtime that the script downloads and executes. Size and SHA-256 checks reduce tampering risk but do not remove the remote binary trust dependency.
Low
Hardcoded URL
"https://modelscope.cn/models/xiaowu89/BiRefNet-GGUF/resolve/master/nx-matting-vulkan.exe"
This URL supplies a native runtime that the script downloads and executes. Size and SHA-256 checks reduce tampering risk but do not remove the remote binary trust dependency.
Low
Hardcoded URL
"https://modelscope.cn/models/xiaowu89/BiRefNet-GGUF/resolve/master/BiRefNet-lite-F16.gguf",
This configured endpoint is used to download a model during normal operation. Integrity checks limit tampering, but the network dependency and parser exposure remain real.
Low
Hardcoded URL
"https://huggingface.co/Acly/BiRefNet-GGUF/resolve/main/BiRefNet-lite-F16.gguf",
This configured endpoint is used to download a model during normal operation. Integrity checks limit tampering, but the network dependency and parser exposure remain real.
Low
Hardcoded URL
"https://hf-mirror.com/Acly/BiRefNet-GGUF/resolve/main/BiRefNet-lite-F16.gguf"
This configured endpoint is used to download a model during normal operation. Integrity checks limit tampering, but the network dependency and parser exposure remain real.
Low
Hardcoded URL
"https://modelscope.cn/models/xiaowu89/BiRefNet-GGUF/resolve/master/BiRefNet-F16.gguf",
This configured endpoint is used to download a model during normal operation. Integrity checks limit tampering, but the network dependency and parser exposure remain real.
Low
Hardcoded URL
"https://huggingface.co/Acly/BiRefNet-GGUF/resolve/main/BiRefNet-F16.gguf",
This configured endpoint is used to download a model during normal operation. Integrity checks limit tampering, but the network dependency and parser exposure remain real.
Low
Hardcoded URL
"https://hf-mirror.com/Acly/BiRefNet-GGUF/resolve/main/BiRefNet-F16.gguf"
This configured endpoint is used to download a model during normal operation. Integrity checks limit tampering, but the network dependency and parser exposure remain real.
Risk Factors
⚙️ External commands (50)
README.md:36-38 README.md:30 README.md:32 README.md:36 README.md:43 scripts/matting.ps1:383 scripts/matting.ps1:386 scripts/matting.ps1:391 scripts/matting.ps1:660 scripts/matting.ps1:391 scripts/matting.ps1:407 scripts/matting.ps1:515 scripts/matting.ps1:660 scripts/matting.ps1:386-391 scripts/matting.ps1:391-660 SKILL.md:24 SKILL.md:25 SKILL.md:26 SKILL.md:28 SKILL.md:29 SKILL.md:30 SKILL.md:52 SKILL.md:54-56 SKILL.md:57-61 SKILL.md:62-66 SKILL.md:70-71 SKILL.md:73-77 SKILL.md:77-78 SKILL.md:78-79 SKILL.md:79-80 SKILL.md:80-81 SKILL.md:81-82 SKILL.md:82-83 SKILL.md:83-87 SKILL.md:87-90 SKILL.md:90-95 SKILL.md:95-96 SKILL.md:96-97 SKILL.md:97 SKILL.md:98 SKILL.md:4 SKILL.md:23 SKILL.md:54 SKILL.md:56 SKILL.md:61 SKILL.md:66 SKILL.md:70 SKILL.md:87 SKILL.md:88 SKILL.md:89
🌐 Network access (12)
README.md:23 references/manifest.json:14 references/manifest.json:15 references/manifest.json:23 references/manifest.json:24 references/manifest.json:35 references/manifest.json:36 references/manifest.json:37 references/manifest.json:45 references/manifest.json:46 references/manifest.json:47 references/manifest.json:57
📁 Filesystem access (6)
Audited by: codex
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APA citation
xiaowu89. (2026). nx-matting security audit report (audit version 1) [Author version 1.0.0]. Skillstore. https://skillstore.io/skills/xiaowu89-nx-matting/audits/1BibTeX citation
@techreport{xiaowu89-xiaowu89-nx-matting-2026,
author = {xiaowu89},
title = {nx-matting security audit report (audit version 1)},
institution = {Skillstore},
year = {2026},
number = {1},
url = {https://skillstore.io/skills/xiaowu89-nx-matting/audits/1},
note = {Author version 1.0.0}
}CITATION.cff
cff-version: 1.2.0
message: "If you use this Skill, cite its author and this versioned security audit report."
title: "nx-matting security audit report (audit version 1)"
version: "1.0.0"
type: report
authors:
- name: "xiaowu89"
date-released: "2026-07-30"
url: "https://skillstore.io/skills/xiaowu89-nx-matting/audits/1"
identifiers:
- type: other
value: "skillstore:xiaowu89-nx-matting:audit:1"
description: "Skillstore immutable audit report identifier"
Skillstore Score
Why this score Evidence Confidence: Medium 77
Architecture
100
Maintainability
87
Content
65
Community
83
Spec Compliance
What You Can Build
Prepare product images
Create transparent PNG product assets for catalogs, stores, and presentations.
Extract portrait subjects
Remove photo backgrounds while preserving people for design compositions.
Create transparent video
Convert recorded subjects into MOV or WebM overlays for editing and web projects.
Try These Prompts
Remove a photo background
Remove the background from [image path]. Save a transparent PNG beside the original without overwriting any file.
Create a product cutout
Use the Full model on [product image path]. Save a high-quality transparent PNG to [output path].
Create a web video overlay
Remove the background from [video path]. Export transparent WebM to [output path] and omit audio.
Control an advanced run
Process [input path] with [CPU or Vulkan], [Lite or Full], cache directory [path], and output [path]. Preserve temporary files for diagnostics.
Best Practices
- Keep the source file unchanged and write results to a separate output path.
- Use the Lite model for previews, then use Full only when edge quality requires it.
- Review alpha edges, video format support, and audio settings before delivery.
Avoid
- Do not overwrite an existing output without explicit approval.
- Do not select the Full model when download size or processing time is constrained.
- Do not assume every editor or browser supports transparent MOV or WebM.
Frequently Asked Questions
Which operating systems are supported?
The provided automation supports Windows x64 with PowerShell.
Does processing upload my media?
Media inference is local. The skill uses network access to download required models, runtimes, and FFmpeg.
Which image formats are accepted?
The skill accepts JPG, PNG, BMP, and WebP images.
Which transparent outputs are available?
Images use transparent PNG. Videos use transparent MOV by default or WebM when requested.
What is the difference between Lite and Full?
Lite is smaller and faster. Full is about 440 MB and targets higher-quality matting.
Is a GPU required?
No. CPU inference is supported, while Vulkan can accelerate processing on compatible systems.
Developer Details
Author
xiaowu89License
MIT
Author version
v1.0.0
Skillstore revision
r1
Ref
57b0aa25b10809a60680af415997d53740bd0049
Maintenance freshness
7/30/2026
Usage
0 downloads · 1 views
File structure