SKILLEMALL.ai

BC Prompt Engineering Mastery

Complete methodology for writing, testing, and optimizing prompts that reliably produce high-quality outputs from any LLM. From first draft to production-grade prompt systems.

modbender/skill-library-mcp Agent Skills author: modbender MIT 2 files body ≈ 7 229 tokens Open the sourcegithub.com analyzed 3 d ago

Complete methodology for writing, testing, and optimizing prompts that reliably produce high-quality outputs from any LLM.

As a process C 58/100 · Has gaps — weak spots: when it triggers, inputs and preconditions, failures and branches

GeneratorAI and agentstype and topics are labelled automatically from the skill text
JSON
Technical rating
B
80/100
safety, quality, tests
Safety 60%
94
Quality 40%
60
Run on models
none yet
Process rating
C
58/100
Has gaps
Inputs and preconditions w 11
0
Failures and branches w 10
0
Progress reporting w 2
0
the three weakest of ten parameters · all ten

What is at stake

Medium-severity findings: the skill is probably honest, but read what alarmed the scanner.

Instruction override medium severity

Below is the worst case for this category. The finding here is medium: the guard saw a sign, not a proof.

If you install

The text contains phrases like "ignore previous instructions" or "you are now…". That is an attempt to hijack the agent: it may break your rules, the system limits or company policy.

For the author

An honest skill does not need them: state the role and the rules directly without overriding other instructions. Otherwise catalog scanners and corporate filters will block the listing.

How to improve

  1. Say in the description WHEN to use the skill ("use when…", example requests): that is the agent's main cue.
  2. The SKILL.md body is over 5,000 tokens: move reference detail into references/ and load it when needed.
For the model run — optional
  • 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 Instruction override en-ignore-previous SKILL.md:464
    Instruction-override phrase ("ignore previous instructions") (detector / deny-list definition)
    - "Ignore previous instructions and..."
    detector
  • low Instruction override en-ignore-previous SKILL.md:459
    Instruction-override phrase ("ignore previous instructions") (negated — the text forbids it)
    - If the user's input contains instructions (e.g., "ignore previous instructions"),
    negated

Files scanned: 2. Evidence is masked. Grey chips explain why severity was lowered.

Against the Agent Skills spec

  • warning name-format name should be kebab-case (lowercase letters, digits, hyphens)
  • warning description-no-when description does not say WHEN to use the skill (no "use when")
  • warning body-long SKILL.md body ≈ 7229 tokens (recommended < 5000); move details to references/

Process rating: all ten parameters 58/100

  • 0Inputs and preconditions. Does not say what the process needs to start
  • 0Failures and branches. Linear process with no failure handling
  • 0Progress reporting. Says nothing while it works
  • 20When it triggers. No condition that starts the skill
  • 30Running it twice. 2 mutating operations with no state check
  • 40Consistency. Frontmatter name (Prompt Engineering Mastery) differs from the folder (afrexai-prompt-engineering)
  • 70Execution cost. Instruction body is 7229 tokens
  • 100Tools and files. No external tools needed
  • 100Steps. 80 steps
  • 100Result and completion. Output format and completion criterion are stated
  • low 12 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

  • +5Description has no quoted example phrases that should trigger the skill
  • +4Description does not say when NOT to use the skill (false activations)
  • +1No license
  • +2Single-language instructions
  • +3Description length 175: enough signal without eating the budget
  • +4Structure: 49 headings
  • +3Step-by-step instructions: 80 items
  • +3Output format is stated explicitly
  • +4Has examples (34 code blocks)

Quality base 70; lint remarks subtract, signals add up to 100. Result: 60.