challenge

challenge is a skill for Claude Code from thoughtbot/rails-consultant. It costs 28 tokens per session (613 once invoked), scanned A, original, MIT.

A Socratic conversation for examining an assumption, decision, or inherited rule. It asks focused questions that make you explain the evidence and reasoning behind your position.

In plain words
What is it for?
Use it to question architecture choices, requirements, Rails conventions, or constraints before committing to them.
Why use it?
It helps reveal when a choice is based on habit or an untested belief instead of a real need.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter.

Part of the rails-consultant plugin — 12 skills shipped together

Good fit Use it to question architecture choices, requirements, Rails conventions, or constraints before committing to them.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/thoughtbot/rails-consultant/challenge
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 thoughtbot/rails-consultant --skill challenge
Clone the repo
git clone --depth 1 https://github.com/thoughtbot/rails-consultant

Made for: Claude Code.

Or install rails-consultant, the plugin that ships this one along with the rest of its 12 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 challenge

README.md
[![agentmods](https://agentmods.dev/badge/skills/thoughtbot/rails-consultant/challenge/github.svg)](https://agentmods.dev/skills/thoughtbot/rails-consultant/challenge)
Your own site
<a href="https://agentmods.dev/skills/thoughtbot/rails-consultant/challenge"><img src="https://agentmods.dev/badge/skills/thoughtbot/rails-consultant/challenge/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 challenge

Your own site · 80×15
<a href="https://agentmods.dev/skills/thoughtbot/rails-consultant/challenge"><img src="https://agentmods.dev/badge/skills/thoughtbot/rails-consultant/challenge.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 613 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 $0.00028 $0.00613
Opus 5.5 $0.00011 $0.00245
Sonnet 5.5 $0.00006 $0.00123
Haiku 4.5 $0.00003 $0.00061

Measured 2mo ago against content hash 875e0dbf4a00, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

challenge 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 2mo 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.

skills/challenge/SKILL.md · 54 lines

How it starts

The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Behavior

This is a conversation, not an audit. Do not produce structured output. Do not list findings upfront. Start by understanding what they actually believe — then follow the thread with one question at a time.

If you already have context — from a prior skill, from the conversation, or from something specific the user said — name the assumption you want to pressure-test and why. Then go straight to questioning. Do not ask them to restate what you already know.

If you do not have context, ask one plain question to surface the assumption before proceeding.

Ask one question at a time, following the gaps in their reasoning. The goal is to make them interrogate the assumption themselves before you weigh in. Good questions to reach for:

On origin:

  • "Where did this belief come from — your own experience, a previous project, something you read, or something someone told you?"
  • "Is this a Rails convention, or did you choose it consciously?"
  • "Have you actually tested this, or is it untested instinct?"

On necessity:

  • "What's the underlying need — if you strip away the solution, what problem must be solved?"
  • "Is this the simplest thing that could work, or are you solving for complexity that doesn't exist yet?" (Beck / XP)
  • "Are you building for now, or for a future that might not arrive?" (YAGNI)

On validity:

  • "Under what conditions would this assumption be wrong?"
  • "What evidence would change your mind?"
  • "Is this cargo-culting — doing it because it's familiar — or is there a real reason?"

On alternatives:

  • "What's the simplest alternative you haven't seriously considered?"
  • "If you couldn't do it this way, what would you do?"
  • "What does Rails already give you that makes this unnecessary?" (convention over configuration)

Have opinions. When an assumption is weak, say so and say why.

When the assumption has been turned over enough — either they've found the weakness themselves, or it's clear they won't without a push — give your verdict directly. Is the assumption valid, partially valid, or worth rejecting? Name the underlying need, name the better path if there is one, and say why.

Close with:

"Did you already suspect this assumption was wrong — or did you genuinely believe it until now?"

Wait for their answer. Respond with one short paragraph: what their answer reveals about how they form and hold assumptions under pressure, and whether they're more likely to inherit bad decisions or make them consciously.

Read the full file on GitHub · 54 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. 2mo ago First seen · 54 lines · 28 tokens per session scan A 875e0dbf4a00

Subscribe to this mod's changes

challenge is a skill published in the GitHub repository thoughtbot/rails-consultant (28 stars, last pushed 6d ago), licensed MIT. It adds 28 tokens to every session and 613 once invoked, about $0.0001 per session on Opus 5.5. 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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