BF ppt-compressor
This skill should be used when the user wants to compress a PowerPoint (.pptx) file by reducing the size of embedded videos and large images. It handles the complete workflow of extracting media from .pptx archives, compressing videos with a bundled ffmpeg (no installation required) and images with Pillow, and repackaging into a valid .pptx file. Trigger phrases include "compress PPT", "reduce PPT size", "compress PowerPoint", "PPT too large", "shrink presentation", "compress videos in PPT", "compress images in PPT", "PPT压缩", "压缩PPT", "PPT文件太大", or any mention of reducing .pptx file sizes involving embedded media. Supports Windows, macOS, and Linux.
As a process F 54/100 · Will not run — References files that are not bundled: scripts/bin/
What is at stake
Medium-severity findings: the skill is probably honest, but read what alarmed the scanner.
Below is the worst case for this category. The finding here is medium: the guard saw a sign, not a proof.
The skill contains commands that delete files, rewrite disks or execute code fetched from the network. The agent may run them without asking if it believes the instructions require it.
Replace destructive commands with safe equivalents that ask for confirmation, scope them to one folder, and stop piping curl into a shell: pin a version and a checksum.
How to improve
- The text references files that are not there: add them or drop the references.
- Your own cases (evals/evals.json, 4–6 real requests with expected answers): the full check would then run those instead of a model-drafted suite.
- A spec.yaml with trigger phrases and assertions — a behaviour contract for CI; `skilltest init` writes a template.
Guard findings · 2
✓ No critical or high findings
Medium and low: 2
-
medium Dangerous commands
cmd-quarantine-fileSKILL.md:398Removes the macOS quarantine flag from one file (usual for a downloaded CLI; make sure the file is the intended binary)xattr -d com.apple.quarantine "{SKILL_DIR}/scripts/bin/ffmpeg" -
medium Dangerous commands
cmd-quarantine-fileSKILL.md:399Removes the macOS quarantine flag from one file (usual for a downloaded CLI; make sure the file is the intended binary)xattr -d com.apple.quarantine "{SKILL_DIR}/scripts/bin/ffprobe"
Files scanned: 6. Evidence is masked. Grey chips explain why severity was lowered.
Against the Agent Skills spec
- warning
missing-refreference to a missing file: scripts/bin/
Process rating: all ten parameters 54/100
- 0Tools and files. 1 referenced file(s) missing: scripts/bin/
- 0Result and completion. Does not say what the result is
- 0Progress reporting. Says nothing while it works
- 40Consistency. Frontmatter name (ppt-compressor) differs from the folder (ppt-compress-master)
- 70When it triggers. States when to use, but not when not to
- 70Inputs and preconditions. Inputs and preconditions are listed
- 100Steps. 61 steps
- 100Failures and branches. 2 branches, has a failure section
- 100Execution cost. Instruction body is 3881 tokens
- 100Running it twice. No mutating operations
- low 10 top-level sections: this looks like several domains in one skill
Everything here is measured from the skill text rather than judged by a model, so the numbers are checkable. A parameter weighs more when it is a more common reason for the process to stall.
Quality signals
- +4Description does not say when NOT to use the skill (false activations)
- +3Output format is not stated: the model decides each time
- -4Absolute local paths (C:\Users, /home/…): not portable
- +1No license
- +2Single-language instructions
- +5Description quotes 8 example trigger phrases
- +3Description length 657: enough signal without eating the budget
- +4Structure: 44 headings
- +3Step-by-step instructions: 61 items
- +4Has examples (25 code blocks)
- +3All 4 scripts are documented
Quality base 70; lint remarks subtract, signals add up to 100. Result: 82.