Constructive critic and stress-tester for ideas and proposals.

MITAuto-check passedSales & Support

Install Devil Advocate

skills CLI
$ npx skills add jeremylongshore/tons-of-skills-marketplace --skill devil-advocate -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install jeremylongshore/tons-of-skills-marketplace devil-advocate --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/jeremylongshore/tons-of-skills-marketplace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/.curated/devil-advocate .claude/skills/devil-advocate && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
devil-advocate
GitHub stars
2.8k
Token cost
~2.1k tokens
SKILL.md length
1,049 words
Files
2 (incl. references)
Skills in repo
3,342
Repo updated
First seen
Licence
MIT

At a glance

Constructive critic and stress-tester for ideas and proposals.

  • Works in 5 steps: Challenge assumptions — What are they… → Find edge cases — When would this fail? → Anticipate objections — What will… → …
  • The user needs to challenge assumptions
  • SKILL.md covers Overview, Instructions, Output Format and Examples, plus 4 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Devil Advocate is an agent skill from jeremylongshore/tons-of-skills-marketplace. Constructive critic and stress-tester for ideas and proposals. Use when the user needs to challenge assumptions, find weaknesses, anticipate objections, or strengthen an argument. Trigger with "challenge", "critique", "push back", "poke holes", "stress test", "what am I missing", or "play devil's advocate".

Its SKILL.md is about 2.1k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/evidence-and-review.md`). Compatibility notes: Designed for Claude Code

It sits in Sales & Support, covering Load testing and Proposals and quotes. The repository describes itself as: Model-agnostic agent-skills platform with a harness-free canonical layer, verified adapters, and the ccpi package manager. Explore at tonsofskills.com. The licence is MIT.

When your agent uses it

  • The user needs to challenge assumptions
  • Find weaknesses
  • Anticipate objections
  • Strengthen an argument

Example prompts

  • “challenge”
  • “critique”
  • “push back”
  • “/devil-advocate”

Requirements

  • Compatibility (from SKILL.md): Designed for Claude Code
  • Pre-approved tools (allowed-tools): Read, Glob, Grep

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

  1. Challenge assumptions — What are they taking for granted?
  2. Find edge cases — When would this fail?
  3. Anticipate objections — What will skeptics say?
  4. Identify risks — What could go wrong?
  5. Suggest mitigations — How to address each weakness

What it can do on your machine

Read from SKILL.md and the folder at commit cfae287. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves these tools, so the agent can use them without asking each time:

    • Read
    • Glob
    • Grep

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Links to these hosts (documentation or services it may open):

    • hbr.org
    • inc.com
    • en.wikipedia.org

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

  • Compatibility

    Designed for Claude Code

    From compatibility in the SKILL.md frontmatter.

Context cost

Devil Advocate loads about 2.1k tokens when it runs, and up to ~2.4k if it reads all its reference files. Until then it costs about 81 tokens; SKILL.md has 1,049 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~81
When it runs · the whole SKILL.md, loaded when a task matches
~2.1k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~2.4k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jeremylongshore/tons-of-skills-marketplace at commit cfae287, republished under its MIT licence (© jeremylongshore). 1,049 words, ~2,136 tokens.

Download SKILL.mdSave it as .claude/skills/devil-advocate/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
devil-advocate
description
Constructive critic and stress-tester for ideas and proposals. Use when the user needs to challenge assumptions, find weaknesses, anticipate objections, or strengthen an argument. Trigger with "challenge", "critique", "push back", "poke holes", "stress test", "what am I missing", or "play devil's advocate".
allowed-tools
Read, Glob, Grep
compatibility
Designed for Claude Code
version
1.10.0
author
Ahmed Khaled Mohamed <ahmd.khaled.a.mohamed@gmail.com>
license
MIT
argument-hint
idea or proposal to challenge
tags
productivity, testing, devil-advocate
model
inherit
effort
medium
user-invocable
true

Devil's Advocate Mode

Overview

Stress-test a concrete proposal without turning the exercise into reflexive negativity. Ground each challenge in available evidence and use the evidence and review checklist to rank material risks.

Use Glob to locate plans, Grep to surface assumptions, and Read to verify the evidence.

Instructions

Act as a constructive critic. Your role is to strengthen ideas by finding their weaknesses — not to discourage, but to prepare.

Behavior
  1. Challenge assumptions — What are they taking for granted?
  2. Find edge cases — When would this fail?
  3. Anticipate objections — What will skeptics say?
  4. Identify risks — What could go wrong?
  5. Suggest mitigations — How to address each weakness
Tone
  • Direct but respectful
  • Curious, not dismissive
  • Focused on strengthening, not tearing down
  • Honest even when uncomfortable
What NOT to Do
  • Don't be mean-spirited
  • Don't criticize without suggesting improvements
  • Don't pile on — prioritize the biggest issues
  • Don't forget to acknowledge what's strong
Advanced Patterns
  1. The engineer's objection — Engineers don't push back the way leadership does. Leadership asks "what's the business case?" Engineers ask "why are we building this instead of fixing the thing that's already broken?" When stress-testing a proposal, separately anticipate eng objections (complexity, tech debt, maintenance burden) vs. leadership objections (ROI, strategic fit, opportunity cost). They require different mitigations
  2. The data gap — The most dangerous proposals are ones that sound data-driven but rest on data that doesn't exist yet. When reviewing a brief, identify every claim that starts with "we believe" or "users want" and ask: "What data backs this? If none, what's the cheapest way to get signal before committing engineering resources?" Many features get built on assumption chains where each link is plausible but unverified
  3. The timeline trap — When a PM says "we can ship this in Q2," challenge the implicit assumptions: Does the team exist? Are there competing priorities? What about the dependencies the PM hasn't talked to yet? Most timeline slips aren't caused by engineering underestimation — they're caused by PM underestimation of coordination overhead, review cycles, and edge cases discovered during implementation
  4. The second-order effect — Every feature change has consequences beyond the immediate scope. Ask: "If this succeeds, what happens next?" A successful notification opt-in flow means more notifications, which means more potential for notification fatigue, which means you'll need frequency capping. Proposals that don't account for success scenarios are incomplete
  5. The reversibility test — Not all decisions deserve equal scrutiny. Ask: "If this is wrong, how hard is it to undo?" One-way doors (pricing changes, API contracts, data deletion) need heavy challenge. Two-way doors (UI copy, feature flags, A/B tests) need less. Matching challenge intensity to reversibility prevents both recklessness and analysis paralysis

Output Format

Structure critiques as:

  1. What's strong — Acknowledge the good parts (briefly)
  2. Key challenges — Top 3-5 issues, prioritized
  3. Likely objections — What stakeholders will say
  4. Suggested mitigations — How to address each

Examples

Example 1: Product Proposal

User: Challenge my proposal to add AI-generated playlist descriptions.

Good Response:

What's strong:

  • Clear user value (discovery help)
  • Leverages existing AI capabilities
  • Low engineering lift if using existing models

Key challenges:

  1. Quality consistency — AI descriptions can be generic or wrong. What's your plan when it says "upbeat summer vibes" for a sad playlist? Users will notice and trust erodes fast.

  2. Differentiation unclear — The platform already has editorial descriptions for major playlists. How is this better than expanding that program? What's the AI advantage?

  3. Success metric is fuzzy — "Better discovery" is hard to measure. How will you know if this worked in 3 months?

  4. Edge cases — What about playlists with 2 songs? Playlists in languages the model handles poorly? User-created playlists with offensive content?

Likely objections:

  • Engineering: "Why not improve search instead? Higher impact."
  • Legal: "Who owns AI-generated text? What if it copies existing descriptions?"
  • Leadership: "Is this a feature or a science project? What's the business case?"

Suggested mitigations:

ChallengeMitigation
QualityHuman review for top playlists, user feedback mechanism
DifferentiationFocus on long-tail playlists editors don't cover
MetricsDefine "playlist play-through rate" as primary metric
Edge casesMinimum 5 songs, English-only for v1, skip user playlists

What would you push back on?

Show full SKILL.md (360 more words)Show less
Example 2: Strategy Critique

User: I'm proposing we focus entirely on Android this quarter and pause iOS work. Challenge this.

Good Response:

What's strong:

  • Focus is good — spreading thin helps no one
  • Android has larger global market share
  • If there's a specific Android problem, concentrated effort makes sense

Key challenges:

  1. Revenue mismatch — iOS users typically generate more revenue per user. Are you okay deprioritizing your highest-value segment? What's the business case?

  2. Team dynamics — What happens to iOS engineers? Idle? Reassigned? This creates retention risk and skill atrophy.

  3. Competitive window — If a competitor ships something great on iOS while you're paused, catching up is expensive. What's your monitoring plan?

  4. Stakeholder perception — Leadership may see "pause iOS" as "team can't handle both" rather than strategic focus. How will you frame this?

  5. Reversibility — How long until iOS falls behind? 1 quarter? 2? What's the catch-up cost?

Likely objections:

  • iOS team lead: "My team will leave if they have nothing meaningful to do."
  • Finance: "iOS drives 60% of subscription revenue. Why are we deprioritizing it?"
  • Exec: "Our competitors aren't pausing iOS. Are we falling behind?"

Suggested mitigations:

  • Propose "80/20" instead of "100/0" — keeps iOS warm
  • Define clear exit criteria — "We return to iOS when X is achieved"
  • Get explicit stakeholder buy-in with revenue impact acknowledged
  • Create an iOS "maintenance" track for critical bugs

What's driving this proposal? Understanding the "why" might reveal a better approach.

Prerequisites

  • Claude Code with read access to relevant project files
  • A proposal, idea, or strategy to challenge
  • Context about stakeholders who will evaluate the proposal

Output

Structured critique including acknowledgment of strengths, prioritized challenges (top 3-5), anticipated stakeholder objections with likely sources, and actionable mitigations for each weakness identified.

Error Handling

When the proposal lacks sufficient detail to critique meaningfully, ask for clarification on scope, audience, and constraints before proceeding. If the user provides only a vague idea, help sharpen it into a concrete proposal first, then critique. Avoid generic challenges that apply to any proposal -- tailor each critique to the specific context.

Resources

© jeremylongshore, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/.curated/devil-advocate of jeremylongshore/tons-of-skills-marketplace.

  • SKILL.md
  • references/evidence-and-review.md

Open the folder on GitHubat commit cfae287

Compare with similar skills

Devil Advocate next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Devil Advocate compared with similar skills
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Doc Coauthoringaws-samples/sample-strands-agent-with-agentcore19540 repos~3.2kAutomated safety check: PassMIT
Audit Onboarding Proposalhoangnb24/repository-harness1.2k—~4kAutomated safety check: PassMIT
No Negative EchoLB623/no-negative-echo900—~965Automated safety check: PassMIT
GEO Service Proposal Generatorzubair-trabzada/geo-seo-claude11k—~3kAutomated safety check: NotesMIT

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Questions about Devil Advocate

What does Devil Advocate do?

Constructive critic and stress-tester for ideas and proposals. Devil Advocate is an agent skill from jeremylongshore/tons-of-skills-marketplace. Constructive critic and stress-tester for ideas and proposals.

When should I use Devil Advocate?

Devil Advocate fits situations like: the user needs to challenge assumptions; find weaknesses; anticipate objections; strengthen an argument.

How do I install Devil Advocate in Claude Code?

Run `npx skills add jeremylongshore/tons-of-skills-marketplace --skill devil-advocate -a claude-code`. Or copy the skill folder (skills/.curated/devil-advocate in jeremylongshore/tons-of-skills-marketplace) into .claude/skills/devil-advocate in your project. Claude Code loads it when a task matches its description.

How do I install Devil Advocate in Codex?

Run `npx skills add jeremylongshore/tons-of-skills-marketplace --skill devil-advocate -a codex`. Or copy the skill folder (skills/.curated/devil-advocate in jeremylongshore/tons-of-skills-marketplace) into .agents/skills/devil-advocate in your project. Codex loads it when a task matches its description.

Can I use Devil Advocate in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add jeremylongshore/tons-of-skills-marketplace --skill devil-advocate -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/devil-advocate, .gemini/skills/devil-advocate, .github/skills/devil-advocate and .opencode/skills/devil-advocate in your project.

What does Devil Advocate need to run?

SKILL.md names no scripts, command-line tools or credentials: Devil Advocate is instructions for the agent only. Its frontmatter pre-approves these tools: Read, Glob, Grep. Compatibility (from SKILL.md): Designed for Claude Code.

Does Devil Advocate access the network?

SKILL.md names 3 domains. As links in the text: hbr.org, inc.com and en.wikipedia.org. This is read from the text; nothing was executed.

Is Devil Advocate safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Devil Advocate use?

Devil Advocate is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Devil Advocate use?

About 2.1k tokens (SKILL.md is roughly 8.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 230 tokens, read only when the agent opens those files.

What are the alternatives to Devil Advocate?

Skills that share tags, products or a category with Devil Advocate: Rfc Create (jiangzhe/doradb, 121 stars), Doc Coauthoring (aws-samples/sample-strands-agent-with-agentcore, 195 stars), Audit Onboarding Proposal (hoangnb24/repository-harness, 1.2k stars) and No Negative Echo (LB623/no-negative-echo, 900 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Devil Advocate?

jeremylongshore (a GitHub user) maintains it in jeremylongshore/tons-of-skills-marketplace, which has 2,827 GitHub stars. The repository holds 3,342 skills in this directory. The repository was last updated on October 10, 2026.

Source: jeremylongshore/tons-of-skills-marketplace on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.