verifying-external-behavior SKILL.md skillA
verifying-external-behavior from kajisho5/ffmpeg-skill is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add kajisho5/ffmpeg-skill/verifying-external-behavior@git:20260906.24c1610Pins git:20260906.24c1610 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- kajisho5/ffmpeg-skill
- Path
.claude/skills/verifying-external-behavior/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260906.24c1610, committed Sep 6, 2026
- Size
- 10,913 bytes
- Repository stars
- 2,026
- License
- MIT
Confirms what a third-party library, remote API, build backend, or scraped document actually does before writing code that depends on it — throwaway probes that run in seconds, permissive clients that forward wrong arguments instead of rejecting them, per-endpoint docs that don't generalize, response shapes that make a "fast path" always-false, fakes that encode your assumption rather than the service's behavior, and dry-runs that skip the step that fails. Use when integrating a new dependency…
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
# Verifying External Behavior
Most integration bugs are not coding errors. They are a belief about someone
else's system — a status code, a parameter name, a response shape, a build
backend's scoping rule — that was never checked and turned out to be wrong. The
code is written correctly against a contract that does not exist.
The fix is not more care. It is a **probe**: a throwaway command that asks the
real system the exact question, before the code is written. Probes cost seconds.
The bugs they prevent are silent, ship green, and are found months later.
## Probe the exact call you are about to write
Not a similar call, not the documented example — the same endpoint form, the same
library version, the same argument spelling.
```bash
# A library's real defaults / return shapes, with no venv to create or clean up
uv run --no-project --with somelib python -c "import somelib; print(somelib.Thing())"
# The exact URL, including the collection-vs-item distinction
curl -s -o /dev/null -w '%{http_code}\n' https://api.example.com/v1/things
curl -s -o /dev/null -w '%{http_code}\n' https://api.example.com/v1/things/1
# What a build backend actually put in the artifact
…Read the whole file at its exact version.
How to install
mdr add kajisho5/ffmpeg-skill/verifying-external-behavior@sha256:212ee8a1246a05efThe line at the top of this page pins the label git:20260906.24c1610, 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_vrnpgcokzg6u33oi)
6 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Sep 6, 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 (10913 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
kajisho5/ffmpeg-skill · 2,026 stars · license MIT · pushed 2026-10-20 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_vrnpgcokzg6u33oi GET https://markdownregistry.com/api/v1/resolve?ref=kajisho5/ffmpeg-skill/verifying-external-behavior GET https://markdownregistry.com/api/v1/blob/212ee8a1246a05ef580820ff7d759f83c81ec235b6a2f73a7d6c08e007b12671
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.
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