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.
npx skills add joshuadavidthomas/agent-skills --skill improving-promptsgit clone --depth 1 https://github.com/joshuadavidthomas/agent-skillsWrote 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/skills/joshuadavidthomas/agent-skills/improving-prompts)<a href="https://agentmods.dev/skills/joshuadavidthomas/agent-skills/improving-prompts"><img src="https://agentmods.dev/badge/skills/joshuadavidthomas/agent-skills/improving-prompts/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/skills/joshuadavidthomas/agent-skills/improving-prompts"><img src="https://agentmods.dev/badge/skills/joshuadavidthomas/agent-skills/improving-prompts.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 | $0.00107 | $0.01229 |
| Opus 5 | $0.00053 | $0.00615 |
| Sonnet 5 | $0.00021 | $0.00246 |
| Haiku 4.5 | $0.00011 | $0.00123 |
Grade A, and why
improving-prompts 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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 114 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Improving Prompts
Overview
Apply current documented Anthropic best practices to existing prompts. Do not invent "improvements" — use the actual guidance.
When to Use
- Optimizing CLAUDE.md or AGENTS.md files
- Improving custom command prompts
- Refining skill instructions
- Migrating prompts to current Claude models (4.x)
When NOT to Use
- Writing new prompts from scratch (just follow best practices directly)
- The prompt is working well and the user hasn't identified issues
The Core Problem
Without this skill, agents:
- Invent "best practices" from general knowledge
- Make structural changes without asking what's broken
- Add complexity assuming more structure = better
- Change things to demonstrate value rather than solve problems
Stop If You Catch Yourself
These are the failure modes. If you think any of these, stop and get a concrete issue first.
| Thought | Reality |
|---|---|
| "It's too vague / not best-practice / inconsistent" | Not actionable. Which specific behavior fails? |
| "I have enough context" / "I'll assume the user wants…" | If you can't name the specific failure, you don't. Ask. |
| "I'm the expert" / "This is how I'd write it" | Authority doesn't bypass a concrete issue. You're not the user. |
| "Based on general best practices…" | Use documented practices. Cite the guidance. |
| "Structure is always better" | Structure solves structure problems, not all problems. |
| "Time pressure — demo tomorrow" | Pressure is when the worst changes get made. |
| "This is obviously an improvement" | Obvious to you ≠ solving the user's actual problem. |
| Making 10+ changes to a short prompt | Stop. What specific problem are you solving? |
Required Process
Step 1: Understand Before Changing
Before ANY modifications:
- Ask what specific behaviors are underperforming
- Ask what the prompt should achieve that it currently doesn't
- If the user says "just improve it generally" — ask for at least one concrete issue
What ships with it
1 file 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.
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.
- 11d ago First seen · 114 lines · 107 tokens per session scan A 5b38c681c5f3
improving-prompts is a skill published in the GitHub repository joshuadavidthomas/agent-skills (49 stars, last pushed 1mo ago), licensed MIT. It adds 107 tokens to every session and 1,229 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.
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