prompt-writer

prompt-writer is a skill for Claude Code from anilcancakir/claude-code-plugin. It costs 45 tokens per session (1,672 once invoked), scanned A, original, MIT.

A guide for writing compact prompts for Claude Code extensions such as skills, agents, commands, and rules.

In plain words
What is it for?
Use it to design or improve extension prompts, keep skill descriptions within their limits, and organize instructions into metadata, main guidance, and optional references.
Why use it?
It helps prompts give the model the needed project-specific instructions without repeating information Claude Code already provides.

Skill for Claude Code

Written for Claude Code: when-to-use in frontmatter. Also seen: mentions CLAUDE.md; mentions Claude Code.

Part of the ac plugin — 6 skills, 9 commands, 2 hooks shipped together

Good fit Use it to design or improve extension prompts, keep skill descriptions within…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/anilcancakir/claude-code-plugin/prompt-writer
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 anilcancakir/claude-code-plugin --skill prompt-writer
Clone the repo
git clone --depth 1 https://github.com/anilcancakir/claude-code-plugin

Made for: Claude Code.

Or install ac, the plugin that ships this one along with the rest of its 6 skills, 9 commands, 2 hooks.

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-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/anilcancakir/claude-code-plugin/prompt-writer.svg)](https://agentmods.dev/skills/anilcancakir/claude-code-plugin/prompt-writer)
Your own site
<a href="https://agentmods.dev/skills/anilcancakir/claude-code-plugin/prompt-writer"><img src="https://agentmods.dev/badge/skills/anilcancakir/claude-code-plugin/prompt-writer.svg" alt="Measured on agentmods" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,672 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 $0.00045 $0.01672
Opus 5 $0.00023 $0.00836
Sonnet 5 $0.00009 $0.00334
Haiku 4.5 $0.00005 $0.00167

Measured 6d ago against content hash 97fb7b52b49d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

prompt-writer 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 6d 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.

plugins/ac/skills/prompt-writer/SKILL.md · 177 lines

How it starts

The opening of the file, as written. The whole thing — 177 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Write prompts optimized for Claude Code's model architecture. Every sentence earns its tokens — Claude already knows general concepts.

Core Principles

Progressive disclosure drives all component design. CC loads content in three tiers:

  1. Metadata (~100 tokens per skill in <system-reminder> listing) — description only, 250 char cap
  2. Body (loaded on invocation, compacted to 5k tokens) — SKILL.md content
  3. References (loaded on demand, unlimited) — references/ files read explicitly

Total invoked skills budget: 25k tokens. Challenge every token.

Dedup awareness — CC auto-injects identity, safety rules, tool schemas, permission system, CLAUDE.md cascade, memory instructions, and output formatting. Components must NOT repeat these. Read references/cc-dedup-guide.md for the complete dedup reference before drafting.

Golden rule: Infrastructure instructions = CC provides. Business logic = your component.

Token budget targets:

Level Budget
Skill listing description 250 chars hard cap
SKILL.md body <500 lines, compacted to 5k tokens
Total invoked skills 25k tokens
Agent body 40-80 lines, max 120
Command body 50-200 lines
Rule body 10-40 lines

Sentence Structure

Use imperative mood: "Extract", "Launch", "Run", "Identify", "Verify".

One sentence = one instruction. Keep under 25 words.

Active voice: "Analyze files" not "Files are analyzed".

Replace vague words with concrete rules:

Vague Concrete
"good code" "typed, tested, lint-clean"
"proper error handling" "catch at boundary, rethrow typed"
"appropriate naming" "camelCase methods, PascalCase classes"
"consider performance" "lazy-load collections over 100 items"

Avoid hedging: "Consider", "Try to", "You should", "You might want to", "Be careful with". These waste tokens and weaken instructions.

Section Patterns

Each component type follows a distinct structural pattern. Read references/writing-patterns.md for complete templates with examples.

Read the full file on GitHub · 177 lines

Files

What ships with it

3 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. 6d ago First seen · 177 lines · 45 tokens per session scan A 97fb7b52b49d

Subscribe to this mod's changes

prompt-writer is a skill published in the GitHub repository anilcancakir/claude-code-plugin (2 stars, last pushed 4mo ago), licensed MIT. It adds 45 tokens to every session and 1,672 once invoked, about $0.0002 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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