These five prompts are designed to be used before you finalize any significant plan. Each one addresses a specific cluster of cognitive bias. Paste your plan summary where indicated and run the prompt as written.
No preamble needed. Start here.
Prompt 1: The Reference Class Check
Addresses: Planning fallacy, optimism bias
I'm planning [brief project description]. My current estimate is [timeline and/or budget].
Before I commit, compare this to the base rate for similar work:
1. What category does this project belong to?
2. What is the typical range of time and cost for this category, based on general patterns?
3. What are the three most common reasons this type of project takes longer than planned?
4. Given typical overrun patterns, what would a calibrated estimate look like?What to do with the output: If the calibrated estimate is meaningfully higher than your current estimate, adjust before committing. If you still prefer the original estimate, you need to name specifically why your project is different from the reference class—and that reasoning should be explicit, not intuitive.
Prompt 2: The Pre-Mortem
Addresses: Confirmation bias, optimism bias, narrative fallacy
I want to run a pre-mortem on this plan: [paste your plan or a one-paragraph summary].
Assume it is [target end date] and the plan has clearly failed—not a minor miss but an obvious failure.
Generate the five most plausible explanations for why it failed. For each:
- Describe the failure mode specifically
- Identify which assumption in the plan this failure invalidates
- Rate the probability as: high, medium, or low
Focus on common, realistic failure modes—not rare catastrophes.What to do with the output: For each high-probability failure mode, decide: revise the plan to reduce the probability, add a contingency, or document a trigger condition that will prompt reassessment if it starts materializing.
Prompt 3: The Assumption Audit
Addresses: Narrative fallacy, overconfidence, Dunning-Kruger
Here is my plan: [paste plan].
Identify the key assumptions each major milestone depends on. For each assumption, categorize it as:
- Verified: backed by direct evidence or confirmed data
- Inferred: reasonable analogy from related experience
- Untested: assumed or believed but not yet confirmed
For each untested assumption in a critical-path milestone, describe what evidence would move it to verified.What to do with the output: Untested assumptions in critical-path milestones are your highest-risk items. For each one, decide whether you can run a quick test or confirmation before committing the full plan—a short conversation, a prototype, a literature check.
Prompt 4: The Sunk Cost Trigger
Addresses: Sunk cost fallacy, status quo bias, present bias
For this plan, help me define pre-committed update triggers—conditions I can define now, before I am invested in the outcome.
Describe a specific, observable condition for each of these:
1. Timeline trigger: at what point does a delay indicate the original estimate was wrong rather than just delayed?
2. Assumption trigger: what evidence would indicate a core assumption has been invalidated?
3. Resource trigger: what signal shows the capacity estimates were significantly off?
4. Strategic trigger: what external change would make the rationale for this plan obsolete?
Make these concrete and observable, not vague.What to do with the output: Write these triggers into your plan document or project notes. Review them at the start of each week. If a trigger condition is met, the response is not panic—it is a pre-planned reassessment conversation you already agreed to have.
Prompt 5: The Steel-Man Challenge
Addresses: Confirmation bias, availability heuristic, narrative fallacy
Here is my plan: [paste plan or summary].
Steelman the case against this plan. I want the strongest possible argument that:
1. The approach is wrong—there is a better way to achieve this goal
2. The timing is wrong—this plan should be done at a different time or in a different order
3. The assumptions are wrong—the key beliefs this plan rests on are likely incorrect
Do not soften the critique. I want the strongest version of each objection.What to do with the output: A strong steelman that you cannot rebut is a signal worth taking seriously. You do not have to abandon your plan because an AI found objections—but if you cannot answer the objections, the plan has a problem you have not yet addressed.
Start here: Copy prompt 2, paste a summary of your current plan, and run it. The pre-mortem addresses more biases simultaneously than any other single prompt and takes about ten minutes.
Related reading: How to Debias Plans with AI — The CLEAR Debiasing Framework — 5 Debiasing Techniques Compared
Tags: AI-prompts, debiasing, cognitive-bias, planning, quick-win
Frequently Asked Questions
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Can I use these prompts in any AI chat tool?
Yes. These prompts work in Claude, ChatGPT, Gemini, or any AI with conversational ability. Paste your plan text or summary where indicated and run the prompt as written. Claude tends to give more structured analytical responses, which suits the adversarial and assumption-auditing prompts particularly well. -
Should I run all five prompts on every plan?
For high-stakes plans, yes—run all five. For lower-stakes plans, prioritize prompts 1 (reference class) and 2 (pre-mortem). These two address the four most common planning biases in about 20 minutes total. -
How do I use these prompts if I don't have a written plan yet?
Describe your plan in a paragraph. You do not need a formal document. The AI will work with a verbal summary. Writing the summary itself is a useful structuring exercise that often surfaces implicit assumptions before you even run the prompts.