doubt-driven-development

doubt-driven-development is a skill for Claude Code from shennawardana23/skillme. It costs 81 tokens per session (1,933 once invoked), scanned A, original, Apache-2.0.

A review practice that asks a fresh reviewer to actively look for flaws in an important decision or code change before it is finalized.

In plain words
What is it for?
Use it before uncertain architecture choices, significant code commits, production deployments, data migrations, public API changes, or claims the compiler cannot verify.
Why use it?
Long work sessions can make assumptions feel like facts. An adversarial check can expose unsafe reasoning while changes are still easy to make.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents.

Part of the skillme plugin — 137 skills, 2 commands shipped together

Good fit Use it before uncertain architecture choices, significant code commits, production deployments, data migrations, public API changes, or claims the compiler cannot verify.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/shennawardana23/skillme/doubt-driven-development
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 shennawardana23/skillme --skill doubt-driven-development
Clone the repo
git clone --depth 1 https://github.com/shennawardana23/skillme

Made for: Claude Code.

Or install skillme, the plugin that ships this one along with the rest of its 137 skills, 2 commands.

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 doubt-driven-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/shennawardana23/skillme/doubt-driven-development/github.svg)](https://agentmods.dev/skills/shennawardana23/skillme/doubt-driven-development)
Your own site
<a href="https://agentmods.dev/skills/shennawardana23/skillme/doubt-driven-development"><img src="https://agentmods.dev/badge/skills/shennawardana23/skillme/doubt-driven-development/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 doubt-driven-development

Your own site · 80×15
<a href="https://agentmods.dev/skills/shennawardana23/skillme/doubt-driven-development"><img src="https://agentmods.dev/badge/skills/shennawardana23/skillme/doubt-driven-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,933 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 $0.00081 $0.01933
Opus 5 $0.00041 $0.00966
Sonnet 5 $0.00016 $0.00387
Haiku 4.5 $0.00008 $0.00193

Measured 8d ago against content hash 179e2e6c0c33, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

doubt-driven-development 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 8d 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/doubt-driven-development/SKILL.md · 179 lines

How it starts

The opening of the file, as written. The whole thing — 179 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Doubt-Driven Development

A confident answer is not a correct one. Long sessions accumulate context that quietly turns assumptions into "facts" without anyone noticing. Doubt-driven development materializes a fresh-context reviewer — biased to disprove, not approve — before a non-trivial output stands. This is not a final code review: a final review judges a finished artifact, while this is an in-flight posture applied while course-correction is still cheap.

When to use

A decision is non-trivial when at least one is true: it introduces or modifies branching logic; it crosses a module or service boundary; it asserts a property the compiler/type system can't verify (thread safety, idempotence, ordering, invariants); its correctness depends on context a future reader can't see; its blast radius is irreversible (production deploy, data migration, public API change).

Don't use it for: mechanical operations (renaming, formatting, moving files), a clear unambiguous instruction, reading or summarizing existing code, a one-line change with obvious correctness, or when the user has explicitly asked for speed over verification. Doubting every keystroke means shipping nothing.

The process

CLAIM ──→ EXTRACT ──→ DOUBT ──→ RECONCILE ──→ STOP

1. CLAIM — name what stands

State 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 IT MATTERS: a race here corrupts user data and is hard to
                detect in QA.

If you can't write the claim that compactly, it's a vibe, not a decision — surface it before scrutinizing it.

2. EXTRACT — the smallest reviewable unit

A fresh-context reviewer needs the artifact and the contract, not the journey that produced them: the diff or function (not the whole file), the proposal in 3-5 sentences plus the constraints it must satisfy. Strip your own reasoning — handing over conclusions gets back validation of those conclusions, not independent scrutiny. If the unit is too large to hold in mind in one read (a 500-line PR), decompose first.

Read the full file on GitHub · 179 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. 8d ago First seen · 179 lines · 81 tokens per session scan A 179e2e6c0c33

Subscribe to this mod's changes

doubt-driven-development is a skill published in the GitHub repository shennawardana23/skillme (2 stars, last pushed 11d ago), licensed Apache-2.0. It adds 81 tokens to every session and 1,933 once invoked, about $0.0004 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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