file-type-detect SKILL.md skillA
file-type-detect from nebutra/nebutra-sailor is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add nebutra/nebutra-sailor/file-type-detect@v1.0.0Pins v1.0.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- nebutra/nebutra-sailor
- Path
packages/ai/forge-runtime/skills/file-type-detect/SKILL.md- Versions recorded
- 1
- Latest version
- v1.0.0, committed Aug 27, 2026
- Size
- 1,609 bytes
- Repository stars
- 5
- License
- Apache-2.0
Match a file's leading bytes against 180 signatures to name its true format; ZIP/ISO-BMFF/OLE2 containers are opened for real, and a lying extension is tiered benign / mismatch / high-risk.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
## What this skill does
Match a file's leading bytes against 180 signatures to name its true format; ZIP/ISO-BMFF/OLE2 containers are opened for real, and a lying extension is tiered benign / mismatch / high-risk
中文：读取文件头字节，比对 180 条签名，识别文件真实格式；ZIP/ISO-BMFF/OLE2 容器做真实内部读取，扩展名不符按 良性/不符/高风险 分级
## When to use
- Human or agent needs **File Type Detector (Magic Bytes)** (`dev/file-type-detect`).
- Tier: `core` · side-effect: `pure` · meter: `forge.dev.file_type_detect`.
## How to invoke
```http
POST /api/v1/tools/invoke/dev/file-type-detect
Content-Type: application/json
{"input":{"text":"example"}}
```
MCP name: `dev__file-type-detect`
## Engine
- **nebutra-magic-table** 1.0.0
- Upstream: File signature table compiled from format specifications (PNG ISO/IEC 15948, ISO/IEC 14496-12 ftyp, ZIP APPNOTE 6.3.x local file header, POSIX 1003.1 ustar at offset 257, ISO 9660 CD001 at 32769, ECMA-376 OOXML, ODF/EPUB stored mimetype member, JVMS §4.1 class file, ELF gABI, Mach-O)
## Composition (next)
Chain these after a successful run when the job continues:
- (none seeded yet)
## Limits
- Prefer pure/deterministic path; do not invent model calls.
…Read the whole file at its exact version.
How to install
mdr add nebutra/nebutra-sailor/file-type-detect@sha256:d148686fccc7c950The line at the top of this page pins the label v1.0.0, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_x7k7ofz5o5z4kgps)
0 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Aug 27, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (1609 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
nebutra/nebutra-sailor · 5 stars · license Apache-2.0 · pushed 2026-10-22 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_x7k7ofz5o5z4kgps GET https://markdownregistry.com/api/v1/resolve?ref=nebutra/nebutra-sailor/file-type-detect GET https://markdownregistry.com/api/v1/blob/d148686fccc7c950f9937ab7591b5df3cd08160af420984f45490da8e04d06ea
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.