Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add furkangonel/cowrangler --skill prompt-engineergit clone --depth 1 https://github.com/furkangonel/cowranglerWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/furkangonel/cowrangler/prompt-engineer)<a href="https://agentmods.dev/skills/furkangonel/cowrangler/prompt-engineer"><img src="https://agentmods.dev/badge/skills/furkangonel/cowrangler/prompt-engineer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/furkangonel/cowrangler/prompt-engineer"><img src="https://agentmods.dev/badge/skills/furkangonel/cowrangler/prompt-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00023 | $0.00879 |
| Opus 5 | $0.00012 | $0.00439 |
| Sonnet 5 | $0.00005 | $0.00176 |
| Haiku 4.5 | $0.00002 | $0.00088 |
Grade A, and why
prompt-engineer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prompt Engineer Skill
Goal
Transform vague, incomplete, or underperforming prompts into precisely crafted instructions that reliably produce the intended output from an LLM.
Prompt Engineering Fundamentals
The Six Dimensions
Every strong prompt addresses:
- Role — Who is the model? What expertise does it bring?
- Task — What exactly should it do? (verb + noun: "analyze", "write", "classify")
- Context — What background does the model need to succeed?
- Format — What should the output look like? (length, structure, examples)
- Constraints — What should it avoid? (tone, topics, length limits)
- Examples — Few-shot examples for consistency (optional but powerful)
Steps
1. Diagnose the existing prompt (if one exists)
If the user has a prompt that "doesn't work":
- What output is it producing?
- What output is desired?
- Which of the six dimensions is missing or weak?
Name the specific problem before prescribing a fix.
Success criteria: You can say "this prompt fails because [specific reason]."
2. Gather requirements
Ask (or infer from context):
- What model will this run on? (GPT-4, Claude, Gemini, Llama — each has different strengths)
- Is this a system prompt, user prompt, or both?
- Will it be used once or repeatedly at scale?
- What's the most common failure mode the user wants to prevent?
Success criteria: You know the model, use case, and primary failure mode.
3. Write the prompt
Apply these techniques based on the use case:
For complex reasoning tasks:
- Add "Think step by step before answering"
- Use XML tags to separate sections:
<context>,<task>,<format> - Include a "before you respond, check:" section
For consistent formatting:
- Provide an exact output template with placeholders
- Add a negative example: "Do NOT format it like this: [bad example]"
For role-playing/personas:
- Define expertise: "You are a senior [role] with [X] years experience in [domain]"
- Define behavioral constraints: "You communicate in [style]. You never [bad behavior]."
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 94 lines · 23 tokens per session scan A a841f5fda687
prompt-engineer is a skill published in the GitHub repository furkangonel/cowrangler (2 stars, last pushed 2d ago), licensed MIT. It adds 23 tokens to every session and 879 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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