senior-prompt-engineer

senior-prompt-engineer is a skill for Claude Code from hanamizuki/solopreneur. It costs 91 tokens per session (2,242 once invoked), scanned A, original, MIT.

A guide to improving prompts and checking the quality of AI outputs. It also covers retrieval-augmented generation (RAG), where an AI looks up relevant documents before answering, and workflows that use tools.

In plain words
What is it for?
Use it to create prompt templates, build evaluation sets, compare prompt versions, measure RAG results, inspect token use, and define structured outputs such as JSON.
Why use it?
It replaces guesswork with measurements from representative test cases. This helps reveal whether a prompt change improves answers, document retrieval, output format, or tool use.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the ai-engineer plugin — 2 skills, 1 agent shipped together

Good fit Use it to create prompt templates, build evaluation sets, compare prompt versions, measure RAG results, inspect token use, and define structured outputs such as JSON.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hanamizuki/solopreneur/senior-prompt-engineer
Install

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.

Any agent
npx skills add hanamizuki/solopreneur --skill senior-prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/hanamizuki/solopreneur

Made for: Claude Code.

Or install ai-engineer, the plugin that ships this one along with the rest of its 2 skills, 1 agent.

Wrote 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.

agentmods badge for senior-prompt-engineer

README.md
[![agentmods](https://agentmods.dev/badge/skills/hanamizuki/solopreneur/senior-prompt-engineer/github.svg)](https://agentmods.dev/skills/hanamizuki/solopreneur/senior-prompt-engineer)
Your own site
<a href="https://agentmods.dev/skills/hanamizuki/solopreneur/senior-prompt-engineer"><img src="https://agentmods.dev/badge/skills/hanamizuki/solopreneur/senior-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.

agentmods 80×15 button for senior-prompt-engineer

Your own site · 80×15
<a href="https://agentmods.dev/skills/hanamizuki/solopreneur/senior-prompt-engineer"><img src="https://agentmods.dev/badge/skills/hanamizuki/solopreneur/senior-prompt-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,242 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00091 $0.02242
Opus 5 $0.00046 $0.01121
Sonnet 5 $0.00018 $0.00448
Haiku 4.5 $0.00009 $0.00224

Measured 12d ago against content hash aac883ec95c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

senior-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 12d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/agent_orchestrator.py, scripts/prompt_optimizer.py, scripts/rag_evaluator.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

plugins/claude/ai-engineer/skills/senior-prompt-engineer/SKILL.md · 140 lines

How it starts

The opening of the file, as written. The whole thing — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Senior Prompt Engineer

Eval-driven prompt engineering, RAG quality measurement, and agent workflow validation. Everything here is model-agnostic by design: techniques are framed by what they do, not by which model generation they were observed on, and the tools never hardcode model IDs or pricing — you supply your provider's current rates when you want dollar figures.

Operating Rules

  1. Never change a prompt without a baseline. Capture metrics first (--analyze --output baseline.json), then compare every iteration against it.
  2. Eval set before optimization. 10–20 representative cases with expected outputs minimum. If the user has no eval set, build one with them before touching the prompt — optimizing against vibes is the #1 failure mode.
  3. Prefer platform features over prompt hacks. If the provider offers native structured outputs / JSON schema enforcement, tool-use APIs, or prompt caching, use those instead of "respond ONLY with JSON" incantations. Prompt-level format enforcement is the fallback, not the default.
  4. Current-generation models need less scaffolding. Don't add chain-of-thought boilerplate, role framing, or few-shot examples reflexively — frontier models often do worse with redundant scaffolding. Add each element only when the eval set shows it helps.
  5. Cost numbers are always user-supplied. Look up the provider's current per-Mtok pricing and pass it via --price-per-mtok (never trust a cached price table — including any you remember).

Tools (exact CLIs, all stdlib)

1. Prompt Optimizer — scripts/prompt_optimizer.py

Static analysis: token estimate, clarity/structure scores (0–100), ambiguity + redundancy detection, few-shot example extraction.

# Full analysis (human-readable report)
python3 scripts/prompt_optimizer.py prompt.txt --analyze

# Save machine-readable baseline for later comparison
python3 scripts/prompt_optimizer.py prompt.txt --analyze --json --output baseline.json

# Token estimate; cost only if you supply your provider's current rate
python3 scripts/prompt_optimizer.py prompt.txt --tokens --model claude --price-per-mtok 3.00

# Whitespace/redundancy-trimmed version
python3 scripts/prompt_optimizer.py prompt.txt --optimize --output optimized.txt

# Extract Input/Output few-shot pairs to JSON
python3 scripts/prompt_optimizer.py prompt.txt --extract-examples --output examples.json

# Compare a revision against the saved baseline
python3 scripts/prompt_optimizer.py optimized.txt --analyze --compare baseline.json

Read the full file on GitHub · 140 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

  1. 12d ago First seen · 140 lines · 91 tokens per session scan A aac883ec95c4

Subscribe to this mod's changes

senior-prompt-engineer is a skill published in the GitHub repository hanamizuki/solopreneur (148 stars, last pushed 26d ago), licensed MIT. It adds 91 tokens to every session and 2,242 once invoked, about $0.0005 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 2026-08-30.