prompt-improver

prompt-improver is a skill for Claude Code, Codex from existential-birds/beagle. It costs 36 tokens per session (1,069 once invoked), scanned A, original, Apache-2.0.

A guide for improving prompts used for coding work, such as implementation, debugging, refactoring, code review, and testing.

In plain words
What is it for?
Use it to rewrite a coding request so the task, investigation, scope, expected result, and verification steps are clear.
Why use it?
It reveals unclear instructions, missing context, weak boundaries, and absent checks that can lead to poor coding results.

Skill for Claude CodeCodex

Part of the beagle-core plugin — 19 skills shipped together

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.

agentmods
npx agentmods add skills/existential-birds/beagle/prompt-improver
Any agent
npx skills add existential-birds/beagle --skill prompt-improver
Clone the repo
git clone --depth 1 https://github.com/existential-birds/beagle

Made for: Claude Code, Codex.

Or install beagle-core, the plugin that ships this one along with the rest of its 19 skills.

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-improver

README.md
[![agentmods](https://agentmods.dev/badge/skills/existential-birds/beagle/prompt-improver.svg)](https://agentmods.dev/skills/existential-birds/beagle/prompt-improver)
Your own site
<a href="https://agentmods.dev/skills/existential-birds/beagle/prompt-improver"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/prompt-improver.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,069 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00036 $0.01069
Opus 5 $0.00018 $0.00535
Sonnet 5 $0.00007 $0.00214
Haiku 4.5 $0.00004 $0.00107

Measured 5d ago against content hash 191352455401, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prompt-improver 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 5d 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/beagle-core/skills/prompt-improver/SKILL.md · 138 lines

How it starts

The opening of the file, as written. The whole thing — 138 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prompt Improver

Optimize code-related prompts for clarity, investigation-first thinking, and verification.

Input

$ARGUMENTS

Step 1: Analyze the Prompt

Evaluate the input prompt across these dimensions:

Dimension What to check
Task Clarity Is the task type clear? (implement, fix, refactor, review, test) Are boundaries defined?
Investigation Does it specify reading/understanding before acting?
Verification Are there appropriate checks? (run tests, build, lint)
Context Anchoring Does it reference specific files, functions, or patterns?
Action Specificity Is the desired outcome explicit? Quality expectations stated?
Scope Control Is it appropriately scoped? Clear stopping points?

Identify which dimensions are weak or missing in the input prompt.

Gates (sequenced)

Complete in order; do not skip steps.

  1. Audit gate (end of Step 1): Pass when the forthcoming Analysis names the task type and either lists each weak or missing dimension from the table or explicitly states all dimensions are adequate, with a brief reason for any dimension you treat as already sufficient.
  2. Transform gate (Step 2): Pass when every improvement you will list under "Improvements Applied" maps to a gap from the audit (or to deliberate strengthening when the prompt was already adequate).
  3. Output gate (Step 3): Pass when the Optimized Prompt block appears only after Gates 1–2 pass.

Step 2: Apply Transformation Rules

Task Clarity

  • Convert vague requests → specific task type + scope
  • Add "implement", "fix", "refactor", "review", or "test" when ambiguous
  • Specify affected files/components when inferable

Investigation-First

  • Add "Read and understand [relevant files] before making changes"
  • For bugs: "Reproduce and understand the root cause first"
  • For features: "Check existing patterns in the codebase"

Anti-Hallucination

  • "Do not assume code structure you haven't read"
  • "Verify imports/dependencies exist before using them"
  • "Check for existing utilities before creating new ones"

Read the full file on GitHub · 138 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. 5d ago First seen · 138 lines · 36 tokens per session scan A 191352455401

Subscribe to this mod's changes

prompt-improver is a skill published in the GitHub repository existential-birds/beagle (80 stars, last pushed 26d ago), licensed Apache-2.0. It adds 36 tokens to every session and 1,069 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 2026-08-30.

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