doubt-driven-development

doubt-driven-development is a skill for Claude Code, Codex from peterblazejewicz/claude-plugins. It costs 74 tokens per session (4,168 once invoked), scanned A, a copy of doubt-driven-development, MIT.

A review approach that challenges important technical decisions from a fresh perspective before they are finalized. It looks for reasons a design or implementation might be wrong rather than simply approving it.

In plain words
What is it for?
Use it for architecture changes, branching logic, module or service boundaries, concurrency, cancellation, public APIs, production deployments, and database migrations.
Why use it?
Long work sessions can turn assumptions into apparent facts, while overlooked risks in cross-system or irreversible changes can be costly later.

Skill for Claude CodeCodex

Part of the dotnet-skills plugin — 24 skills, 9 commands, 4 agents shipped together

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.

agentmods
npx agentmods add skills/peterblazejewicz/claude-plugins/doubt-driven-development
Any agent
npx skills add peterblazejewicz/claude-plugins --skill doubt-driven-development
Clone the repo
git clone --depth 1 https://github.com/peterblazejewicz/claude-plugins

Made for: Claude Code, Codex.

Or install dotnet-skills, the plugin that ships this one along with the rest of its 24 skills, 9 commands, 4 agents.

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/peterblazejewicz/claude-plugins/doubt-driven-development.svg)](https://agentmods.dev/skills/peterblazejewicz/claude-plugins/doubt-driven-development)
Your own site
<a href="https://agentmods.dev/skills/peterblazejewicz/claude-plugins/doubt-driven-development"><img src="https://agentmods.dev/badge/skills/peterblazejewicz/claude-plugins/doubt-driven-development.svg" alt="Measured on agentmods" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,168 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 92% copy Near-identical to another mod 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 $0.00074 $0.04168
Opus 5 $0.00037 $0.02084
Sonnet 5 $0.00015 $0.00834
Haiku 4.5 $0.00007 $0.00417

Measured 4d ago against content hash 116b14b6591a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 4d 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.

Origin

This is a copy

92% identical to doubt-driven-development — 40 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/dotnet-skills/skills/doubt-driven-development/SKILL.md · 258 lines

How it starts

The opening of the file, as written. The whole thing — 258 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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, project, or service boundary (MyApp.CoreMyApp.Infrastructure, a Minimal API surface, a queue consumer)
  • It asserts a property the type system or compiler cannot verify (thread safety, idempotence, ordering, invariants, nullable-reference honesty, async cancellation correctness)
  • Its correctness depends on context the future reader cannot see
  • Its blast radius is irreversible (production deploy, destructive EF Core migration, public/library 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 thread-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, dotnet format)
  • Following a clear, unambiguous user instruction
  • Reading or summarizing existing code
  • One-line changes with obvious correctness
  • Pure tooling operations (running dotnet test, 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.

Read the full file on GitHub · 258 lines

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. 4d ago First seen · 258 lines · 74 tokens per session scan A 116b14b6591a

Subscribe to this mod's changes

doubt-driven-development is a skill published in the GitHub repository peterblazejewicz/claude-plugins (7 stars, last pushed 2mo ago), licensed MIT. It adds 74 tokens to every session and 4,168 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to doubt-driven-development, differing in 40 lines, and is treated as a copy.

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