A lot of better thinking starts with one small move: slowing the question down.

That sounds simple, but it is surprisingly easy to skip. We jump from a problem to an answer, from a plan to a launch date, from a disagreement to a verdict. The Cognitive Bias Lab Critical Thinking Tools plugin is designed to add a small, useful pause in exactly those moments.

Quick idea: this plugin gives Codex and Claude Code a practical thinking toolkit. You bring the messy decision, forecast, disagreement, or plan. The assistant chooses a structured tool and turns the next step into something clearer.

The point is not to make anyone perfectly rational. Human judgment does not work that way. The point is to make the next question a little better.

What the plugin is

The plugin packages 12 critical thinking workflows from Cognitive Bias Lab into reusable assistant skills. Each workflow gives the assistant a clear structure to follow, so the output is not just a generic list of pros and cons.

Each tool asks the assistant to include:

• The tool result
• Likely bias risks
• What evidence would change the conclusion
• A next action
• A short science note

That last part matters. These tools are grounded in psychology, decision science, forecasting research, and intelligence analysis, but they are presented carefully: as judgment aids, not magic debiasing cures.

Canonical repository:

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https://github.com/cognitive-bias-lab/cognitive-bias-lab-plugins

Install it

Claude Code

Copy this into your terminal:

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claude plugin marketplace add cognitive-bias-lab/cognitive-bias-lab-plugins --scope user
claude plugin install critical-thinking-tools@cognitive-bias-lab

Then start a new Claude Code session and ask for a tool by name, or describe the decision you are working through.

Official Claude marketplace directory links are coming once the plugin is accepted and listed there.

Codex

Codex users can use the same public repository as the plugin source of truth. The repository includes the Codex marketplace file at .agents/plugins/marketplace.json and the plugin package at plugins/critical-thinking-tools/.

Open the plugin directory in Codex:

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/plugins

Choose the Cognitive Bias Lab marketplace when it is available in your workspace, then install Critical Thinking Tools.

The official Codex Plugin Directory publishing flow is still becoming available, so the official Codex directory link is coming when public publishing opens.

Use it

The easiest way is to copy one of these prompts and replace the bracketed part with your real situation.

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Use the critical thinking toolkit to choose the right tool for this situation:
[describe the decision, forecast, plan, belief, or disagreement]

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Run a pre-mortem for this plan:
[paste the plan, launch, migration, course, or project]

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Play devil's advocate against this decision:
[paste the decision and the strongest reason for it]

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Build an outside-view checklist for this forecast:
[paste the estimate, timeline, budget, or probability claim]

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Help me compare competing explanations for this observation:
[paste the metric drop, incident, behaviour change, or evidence]

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Create a decision journal for this choice:
[paste the options, context, probabilities, and what I am leaning toward]

A good request gives the assistant three things: the context, the current best answer, and what would make the decision hard.

The 12 tools

1. Devil's advocate

Use this when a decision feels a little too comfortable. It challenges assumptions, looks for disconfirming evidence, and separates objections from action items.

Copyable starter:

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Run a devil's advocate review of this decision. Separate serious objections from fixable concerns, then give me the next action.

2. Pre-mortem

Use this before a plan starts. Imagine the plan has failed, list the likely causes, rank preventability, and turn risks into safeguards.

Good for launches, courses, projects, migrations, events, and anything with hidden execution risk.

3. Outside view

Use this when estimates are built mostly from optimism and local detail. It asks for reference classes, base rates, similar past cases, and planning fallacy checks.

Good for timelines, budgets, forecasts, project scopes, and probability estimates.

4. Competing hypotheses

Use this when several explanations could fit the facts. It builds an evidence-versus-hypotheses matrix inspired by Analysis of Competing Hypotheses.

Good for metric drops, customer behaviour changes, incidents, investigations, and root-cause analysis.

5. Consider the opposite

Use this when you want to test a belief or interpretation. It deliberately generates reasons the preferred answer may be wrong.

Good for confirmation bias checks, controversial opinions, early conclusions, and recommendation reviews.

6. Steelman

Use this when disagreement is getting lazy. It reconstructs the strongest fair version of an opposing position before evaluating it.

Good for debates, product disagreements, policy arguments, and writing that needs intellectual honesty.

7. Socratic ladder

Use this when the thought is still fuzzy. It climbs through terms, evidence, assumptions, alternatives, implications, and confidence.

Good for unclear beliefs, hard trade-offs, coaching conversations, and reflective learning.

8. Base-rate audit

Use this when a number sounds persuasive but the denominator is missing. It checks priors, sample size, selection effects, and vivid anecdote traps.

Good for statistics, risk claims, test results, market claims, and evidence based on a few memorable examples.

9. Causal story dissection

Use this when a story says X caused Y. It separates correlation, mechanism, confounds, missing data, and alternative causes.

Good for analytics, policy claims, health-adjacent claims, business narratives, and post-hoc explanations.

10. Calibration forecasting

Use this when a claim should become a probability. It turns beliefs into forecasts, tracks uncertainty, and makes future updating easier.

Good for predictions, roadmap bets, market expectations, hiring outcomes, and personal planning.

11. Decision journal

Use this before a meaningful decision. It records context, options, probabilities, reasons, and review criteria so you can learn later without outcome bias taking over.

Good for career moves, purchases, launches, hiring, investments, and strategic choices.

12. Groupthink red-team

Use this before a group locks in. It creates safer dissent prompts, anonymous objection rounds, role rotation, and final challenge checks.

Good for leadership meetings, strategy reviews, hiring panels, product reviews, and any team where agreement arrived suspiciously fast.

What it is not

This plugin is not a therapist, lawyer, doctor, financial adviser, or oracle. It will not remove bias from human thinking. Nothing does.

It is better understood as a structured thinking companion: a way to make uncertainty visible, stress-test the story, and turn vague concerns into concrete next steps.

For medical, legal, financial, safety, or mental health decisions, use it alongside qualified expert advice.

Why I made it

Cognitive Bias Lab is about making biases easier to experience, notice, and work with. The website has simulations, practice tools, quizzes, and bias pages. The plugin extends that idea into the places where people already make decisions: code editors, planning sessions, project notes, and messy drafts.

You do not need to memorize every bias to think better. Often you just need the right prompt at the right moment:

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What would make this wrong?
What usually happens in similar cases?
What are we not saying because the group already seems aligned?
What would we write down now so future-us can judge the decision fairly?

That is the spirit of the plugin: not certainty, but better questions.

Marketplace links

The public GitHub repository is live now: cognitive-bias-lab/cognitive-bias-lab-plugins.

• Claude marketplace listing: coming soon
• Codex Plugin Directory listing: coming soon

Until then, the GitHub repository is the canonical source for installation and updates.