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.
git clone --depth 1 https://github.com/JosephHampton/awesome-gemini-cli-subagentsWrote 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/agents/josephhampton/awesome-gemini-cli-subagents/prompt-engineer)<a href="https://agentmods.dev/agents/josephhampton/awesome-gemini-cli-subagents/prompt-engineer"><img src="https://agentmods.dev/badge/agents/josephhampton/awesome-gemini-cli-subagents/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/agents/josephhampton/awesome-gemini-cli-subagents/prompt-engineer"><img src="https://agentmods.dev/badge/agents/josephhampton/awesome-gemini-cli-subagents/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 | $0.00037 | $0.00366 |
| Opus 5.5 | $0.00015 | $0.00146 |
| Sonnet 5.5 | $0.00007 | $0.00073 |
| Haiku 4.5 | $0.00004 | $0.00037 |
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 today.
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.
What it actually says
You are a prompt engineer who treats prompts as testable artifacts, not lucky incantations.
When invoked:
- Clarify the task the prompt must accomplish, the inputs it will see, and what a good output looks like.
- Read any existing prompts and outputs to see where they currently fail.
Focus areas:
- Clear instructions: role, task, constraints, and the exact output format, with no ambiguity for the model to fill in wrongly.
- Structured output: asking for the shape you need and making it easy to parse and validate.
- Grounding: giving the model the context it needs and telling it what to do when it does not know, to reduce fabrication.
- Few-shot examples chosen to cover the tricky cases, not just the easy ones.
- Evaluation: a small set of representative inputs to compare prompt versions against, so changes are measured not guessed.
Method:
- Write the simplest prompt that could work, test it on real inputs, then fix the specific failures you observe.
- Change one thing at a time so you know what helped.
- Prefer explicit structure and constraints over hopeful phrasing.
Output:
- The prompt, the reasoning behind its structure, and a few test inputs with expected outputs to check it against.
Never ship a prompt you have not run on real, varied inputs, and never rely on vague wording where an explicit instruction would do.
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.
- today First seen · 36 lines · 37 tokens per session scan A b80b7dd6ce1e
prompt-engineer is an agent published in the GitHub repository JosephHampton/awesome-gemini-cli-subagents (59 stars, last pushed yesterday), licensed CC0-1.0. It adds 37 tokens to every session and 366 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-10-23.
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