prompt-coach

prompt-coach is a skill for Claude Code from alexmond/alexmskills. It costs 177 tokens per session (8,541 once invoked), scanned A, original, MIT.

An automatic prompt coach for Claude Code that reviews prompts as they are submitted and suggests clearer wording, defined outcomes, relevant file references, safety limits, and verification steps. Its coaching rules become less frequent as they are demonstrated.

In plain words
What is it for?
Use it while writing coding-agent prompts, especially when a request needs a specific file or function, an exact behavior, limits on changes, or tests to confirm the result.
Why use it?
It helps turn vague coding requests into instructions that are easier for an agent to follow and check. This reduces missing context and unclear completion criteria.

Skill for Claude Code

Written for Claude Code: UserPromptSubmit hook event. Also seen: reads .claude/ paths; names the AskUserQuestion tool; mentions Claude Code.

Part of the prompt-coach plugin — 1 skill, 8 commands shipped together

Good fit Use it while writing coding-agent prompts, especially when a request needs a specific file or function, an exact behavior, limits on changes, or tests to confirm the result.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/alexmond/alexmskills/prompt-coach
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 alexmond/alexmskills --skill prompt-coach
Clone the repo
git clone --depth 1 https://github.com/alexmond/alexmskills

Made for: Claude Code.

Or install prompt-coach, the plugin that ships this one along with the rest of its 1 skill, 8 commands.

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-coach

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/alexmond/alexmskills/prompt-coach"><img src="https://agentmods.dev/badge/skills/alexmond/alexmskills/prompt-coach.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 177 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 8,541 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 warn 7 Sept 2026
SkillSpector: 5 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 79
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
  • medium Excessive Agency · line 90
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium Excessive Agency · line 115
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium Excessive Agency · line 161
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
  • medium Excessive Agency · line 202
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 $0.00177 $0.08541
Opus 5 $0.00088 $0.04270
Sonnet 5 $0.00035 $0.01708
Haiku 4.5 $0.00018 $0.00854

Measured 11d ago against content hash 7538c7c99a9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

prompt-coach 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.

plugins/prompt-coach/skills/prompt-coach/SKILL.md · 577 lines

How it starts

The opening of the file, as written. The whole thing — 577 lines — stays where its author put it; the contents beside it link to each section on GitHub.

prompt-coach

Quick start

60-second setup

/plugin marketplace add alexmond/alexmskills
/plugin install prompt-coach@alexmskills
/reload-plugins

Restart the session so the UserPromptSubmit hook registers. Then just prompt Claude normally — the coach analyzes every prompt in the background and nudges when a rule matches.

What you'll see when a rule fires

As of v0.34 the coach is a collaborator (not a nagger): when a rule fires, Claude reads your prompt in context and rewrites it with the fix baked in, at the top of its response:

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
💬 prompt-coach — I read your prompt as:

    "in src/auth/login.js, update handleLogin() to reject empty
     password submissions with a 422 and a 'password required'
     message. Keep the existing test suite green."

Changes:
  [1] Named the file + function (was: 'the login flow')
  [2] Made the behavior explicit + added a guardrail

Sources: https://…/be-clear-and-direct

Proceeding with this rewrite now — reply "no" to redo from your original, or "edit" to adjust.
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
▸ Working from the rewrite.
<Claude answers your question from here, using that prompt.>

On a clean prompt you instead get a one-line heartbeat (v0.35). The coach is a suggestion, not a block — Claude answers your prompt normally. By default (v0.43) it proceeds honestly: the block says it's proceeding (not "reply yes to proceed") and Claude opens with a ▸ Working from the rewrite / your original line so you always see which prompt drove the answer; silence = accept, and a no/edit next turn corrects. Prefer a real pause? Set collaborator_gate: true and Claude stops after the block and waits for your yes/no/edit (one extra round-trip per fired prompt). Rules graduate to "mastered" once you've demonstrated the good technique min_demonstrations times (default 3, v0.40 earned-mastery model), then the next dormant rule activates.

Read the full file on GitHub · 577 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. 11d ago First seen · 577 lines · 177 tokens per session scan A 7538c7c99a9e

Subscribe to this mod's changes

prompt-coach is a skill published in the GitHub repository alexmond/alexmskills (6 stars, last pushed 3d ago), licensed MIT. It adds 177 tokens to every session and 8,541 once invoked, about $0.0009 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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