# Adversarial Decision Review

Cross-examines each non-trivial decision with a fresh-context review before it stands.

- Repository: https://github.com/addyosmani/agent-skills (112533 stars)
- Category: AI and agents
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add addyosmani/agent-skills --skill doubt-driven-development -g -a claude-code -y`
Codex: `npx skills add addyosmani/agent-skills --skill doubt-driven-development -g -a codex -y`
Cursor: `npx skills add addyosmani/agent-skills --skill doubt-driven-development -g -a cursor -y`
Gemini CLI: `npx skills add addyosmani/agent-skills --skill doubt-driven-development -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add addyosmani/agent-skills`

## Description

Subjects every non-trivial decision to a fresh-context adversarial review before it stands. Use when you want every assumption cross-examined before proceeding, when stress-testing a plan for hidden failure modes, when correctness matters more than speed, when working in unfamiliar code, when stakes are high (production auth, security-sensitive logic, a high-stakes migration, irreversible operations), or any time a confident output would be cheaper to verify now than to debug later.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Doubt-Driven Development

## Overview

A confident answer is not a correct one. Long sessions accumulate context that quietly turns assumptions into "facts" without anyone noticing. Doubt-driven development is the discipline of materializing a fresh-context reviewer, biased to **disprove**, not approve, before any non-trivial output stands.

This is not `/review`. `/review` is a verdict on a finished artifact. This is an in-flight posture: non-trivial decisions get cross-examined while course-correction is still cheap.

## When to Use

A decision is **non-trivial** when at least one of these is true:

- It introduces or modifies branching logic
- It crosses a module or service boundary
- It asserts a property the type system or compiler cannot verify (thread safety, idempotence, ordering, invariants)
- Its correctness depends on context the future reader cannot see
- Its blast radius is irreversible (production deploy, data migration, public API change)

Apply the skill when:

- About to make an architectural decision under uncertainty
- About to commit non-trivial code
- About to claim a non-obvious fact ("this is safe", "this scales", "this matches the spec")
- Working in code you don't fully understand

**When NOT to use:**

- Mechanical operations (renaming, formatting, file moves)
- Following a clear, unambiguous user instruction
- Reading or summarizing existing code
- One-line changes with obvious correctness
- Pure tooling operations (running tests, listing files)
- The user has explicitly asked for speed over verification

If you doubt every keystroke, you ship nothing. The skill applies only to non-trivial decisions as defined above.

## Loading Constraints

This skill is designed for the **main-session orchestrator**, where Step 3 (DOUBT, detailed below) can spawn a fresh-context reviewer.

The rest: https://github.com/addyosmani/agent-skills/blob/HEAD/skills/doubt-driven-development/SKILL.md