doubt-driven-development

The saved excerpt is a snapshot from when this skill was listed. The external source remains the complete and most current version.

---
name: doubt-driven-development
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.
---

# 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.

- **Do NOT add this skill to a persona's `skills:` frontmatter.** A persona that follows Step 3 would spawn another persona — the orchestration anti-pattern explicitly forbidden by `../../references/orchestration-patterns.md` ("personas do not invoke other personas").
- **If you find yourself applying this skill from inside a subagent context** (where Claude Code prevents nested subagent spawn): the preferred path is to surface to the user that doubt-driven cannot run nested and let the main session handle it. As a last resort only, a degraded self-questioning fallback exists — rewrite ARTIFACT + CONTRACT as a fresh self-prompt with a hard mental separator from your prior reasoning, and walk Steps 1–5. This is **not fresh-context review** (you carry your own context with you), so flag the result as degraded and prefer escalation whenever the user is reachable.

## The Process

Copy this checklist when applying the skill:

```
Doubt cycle:
- [ ] Step 1: CLAIM — wrote the claim + why-it-matters
- [ ] Step 2: EXTRACT — isolated artifact + contract, stripped reasoning
- [ ] Step 3: DOUBT — invoked fresh-context reviewer with adversarial prompt
- [ ] Step 4: RECONCILE — classified every finding against the artifact text
- [ ] Step 5: STOP — met stop condition (trivial findings, 3 cycles, or user override)
```

### Step 1: CLAIM — Surface what stands

Name the decision in two or three lines:

```
CLAIM: "The new caching layer is thread-safe under the
        read-heavy workload described in the spec."
WHY THIS MATTERS: a race here corrupts user data and is
                  hard to detect in QA.
```