prompt-best-practices

prompt-best-practices is a command for Claude Code from appboypov/pew-pew-plaza-packs. It costs 18 tokens per session (1,622 once invoked), scanned A, original, MIT.

A guide to writing modular prompts that define a clear result and include only useful instructions.

In plain words
What is it for?
Use it to set measurable outcomes, break prompts into focused sections, and decide which instructions belong in a prompt.
Why use it?
It helps avoid vague, oversized prompts that produce inconsistent results or contain instructions unrelated to the goal.

Command for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it to set measurable outcomes, break prompts into focused sections, and decide which instructions belong in a prompt.

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Install with agentmods
npx agentmods add commands/appboypov/pew-pew-plaza-packs/prompt-best-practices
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.

Clone the repo
git clone --depth 1 https://github.com/appboypov/pew-pew-plaza-packs

Made for: Claude Code.

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 prompt-best-practices

README.md
[![agentmods](https://agentmods.dev/badge/commands/appboypov/pew-pew-plaza-packs/prompt-best-practices/github.svg)](https://agentmods.dev/commands/appboypov/pew-pew-plaza-packs/prompt-best-practices)
Your own site
<a href="https://agentmods.dev/commands/appboypov/pew-pew-plaza-packs/prompt-best-practices"><img src="https://agentmods.dev/badge/commands/appboypov/pew-pew-plaza-packs/prompt-best-practices/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 prompt-best-practices

Your own site · 80×15
<a href="https://agentmods.dev/commands/appboypov/pew-pew-plaza-packs/prompt-best-practices"><img src="https://agentmods.dev/badge/commands/appboypov/pew-pew-plaza-packs/prompt-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,622 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.
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 $0.00018 $0.01622
Opus 5 $0.00009 $0.00811
Sonnet 5 $0.00004 $0.00324
Haiku 4.5 $0.00002 $0.00162

Measured 9d ago against content hash 431262a8fcab, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

prompt-best-practices 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.

.claude/commands/apply/prompt-best-practices.md · 285 lines

How it starts

The opening of the file, as written. The whole thing — 285 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Instruction Command

When this command is used, acknowledge that you understand these instructions and will follow them throughout the conversation. Then await the user's request.


🌟 Prompt Best Practices

💡 Industry standards and proven approaches for creating high-quality, maintainable prompts.

Start with End Goal

Define Success First

The End Goal is your north star - it determines whether any other section should exist. Write it as:

  • Specific and measurable
  • Outcome-focused, not process-focused
  • Clear enough that success is unambiguous
  • Concise but complete

Example End Goals

  • ✅ "Generate production-ready Flutter widget tests with 100% coverage"
  • ✅ "Transform user stories into technical implementation plans"
  • ❌ "Help with testing" (too vague)
  • ❌ "Follow the testing process" (process, not outcome)

WHEN defining End Goals

  • ALWAYS make them measurable
  • ALWAYS focus on the outcome
  • ALWAYS keep them concise
  • NEVER include process steps
  • NEVER leave ambiguity

Apply Ruthless Modularity

Include Only What Contributes

Each section must pass the contribution test:

  1. Does this section help achieve the End Goal?
  2. Would the prompt fail without it?
  3. Does it add more value than complexity?

If any answer is "no", exclude the section.

Component Decision Framework

Persona:
- ✅ Include if: Specialized expertise improves outcome
- ❌ Exclude if: General knowledge suffices

Workflow:
- ✅ Include if: Multi-step process with dependencies
- ❌ Exclude if: Single action or simple task

Instructions:
- ✅ Include if: Specific rules prevent common failures
- ❌ Exclude if: Obvious or redundant with Request

Output Format:
- ✅ Include if: Specific structure required
- ❌ Exclude if: Standard text response works

WHEN evaluating components

  • ALWAYS test against End Goal
  • ALWAYS document inclusion rationale
  • ALWAYS prefer exclusion when uncertain
  • NEVER include components by default
  • NEVER add sections "just in case"

Read the full file on GitHub · 285 lines

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. 9d ago First seen · 285 lines · 18 tokens per session scan A 431262a8fcab

Subscribe to this mod's changes

prompt-best-practices is a command published in the GitHub repository appboypov/pew-pew-plaza-packs (85 stars, last pushed 8mo ago), licensed MIT. It adds 18 tokens to every session and 1,622 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 2026-09-03.