devils-advocate

devils-advocate is a skill for Claude Code from CassioRoos/godfly-skills. It costs 109 tokens per session (1,137 once invoked), scanned A, original, MIT.

A structured argument for the opposing side of a technical decision. It builds the strongest case for an alternative or for not proceeding with the proposed plan.

In plain words
What is it for?
Use it before approving migrations, architecture changes, or other significant choices. It helps teams test whether the rejected option or delaying the decision deserves more consideration.
Why use it?
It exposes weak assumptions and risks before they become expensive problems in production. The result is a challenge to a decision, not a general code review.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it before approving migrations, architecture changes, or other significant choices. It helps teams test whether the rejected option or delaying the decision deserves more consideration.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/cassioroos/godfly-skills/devils-advocate
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 CassioRoos/godfly-skills --skill devils-advocate
Clone the repo
git clone --depth 1 https://github.com/CassioRoos/godfly-skills

Made for: Claude Code.

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 devils-advocate

README.md
[![agentmods](https://agentmods.dev/badge/skills/cassioroos/godfly-skills/devils-advocate.svg)](https://agentmods.dev/skills/cassioroos/godfly-skills/devils-advocate)
Your own site
<a href="https://agentmods.dev/skills/cassioroos/godfly-skills/devils-advocate"><img src="https://agentmods.dev/badge/skills/cassioroos/godfly-skills/devils-advocate.svg" alt="Measured on agentmods" height="20"></a>
Per session 109 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,137 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 $0.00109 $0.01137
Opus 5 $0.00055 $0.00568
Sonnet 5 $0.00022 $0.00227
Haiku 4.5 $0.00011 $0.00114

Measured 7d ago against content hash 8c5a56f2e4c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

devils-advocate 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 7d 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/devils-advocate/SKILL.md · 77 lines

How it starts

The opening of the file, as written. The whole thing — 77 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Devil's Advocate - Opposing Counsel

A decision is about to be made. Your job is to argue the other side like you actually believe it. Not to nitpick the chosen path - to build the strongest possible case that the alternative is right, or that the decision shouldn't happen at all. Better to hear the opposition in the lab than from reality in production.

Core Principle

Steelman the alternative, don't strawman it. A devil's advocate who argues half-heartedly is worse than none - it inoculates the decision against real opposition without testing it. Argue as if you were paid to win.

The Opposing-Brief Protocol

1. State the Position Being Opposed

One sentence. Name the decision, the chosen path, and what it's being chosen over.

"The team is about to migrate the billing service to event sourcing instead of keeping the current CRUD model."

If you can't state it in one sentence, the decision isn't crisp enough to oppose - sharpen it first.

2. Build the Brief

Argue for the other side across four fronts:

  • Attack the load-bearing assumptions. Every decision rests on a few claims that, if false, collapse the whole case. Name them explicitly and argue why each could be wrong. Not the peripheral assumptions - the ones the decision cannot survive without.
  • Present the alternative's genuine benefits. What does the rejected path actually do well? Argue its merits as its best advocate would - concrete benefits, not faint praise. If the alternative is "do nothing," argue the real value of the status quo: stability, optionality, resources freed for other bets.
  • Name the costs and irreversibilities of the chosen path. What does this decision spend that can't be recovered - time, money, credibility, architectural flexibility? Which doors does it close? One-way doors deserve far harder opposition than two-way doors.
  • State the conditions under which the opposition wins. Under what circumstances does the alternative turn out to be right? Be specific: "If migration takes longer than one quarter," "if the vendor raises prices," "if the team loses its one event-sourcing expert." These are the scenarios where this brief becomes prophecy.

Read the full file on GitHub · 77 lines

Files

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.

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. 7d ago First seen · 77 lines · 109 tokens per session scan A 8c5a56f2e4c4

Subscribe to this mod's changes

devils-advocate is a skill published in the GitHub repository CassioRoos/godfly-skills (1 stars, last pushed 7d ago), licensed MIT. It adds 109 tokens to every session and 1,137 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 2026-08-31.

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