Assumption Challenger

Systematically surfaces and stress-tests assumptions treated as facts but never validated. Most failures trace back to invalid assumptions — catching them early prevents costly mistakes.

Assumption Categories

1. Timeline Assumptions

Assumptions about how long things will take.

Red flags: "This should only take...", "If everything goes well...", "The team can absorb this..."

Challenge with:

• What's this estimate based on? Past experience or hope?
• What similar work has been done before? How long did it actually take?
• What's NOT included? (Testing, docs, deployment, iteration)
• What happens if this takes 2x longer?

2. Resource Assumptions

Assumptions about team capacity and availability.

Red flags: "We'll hire by Q2...", "The team can support this...", "Sarah can lead this while..."

Challenge with:

• What's the actual hiring timeline? What if you can't find the right people?
• What's the team's current utilization? Where does time come from?
• Who's the backup if the key person is unavailable?
• What happens at 50% of expected capacity?

3. Technical Assumptions

Assumptions about system capabilities and constraints.

Red flags: "The system can handle the load...", "We can integrate easily...", "Our architecture supports..."

Challenge with:

• Has this been tested at the required scale?
• What are the documented limits? What happens at those limits?
• What's the failure mode? How do you recover?
• Have you talked to the API provider about your usage patterns?

4. Business Assumptions

Assumptions about market, users, and outcomes.

Red flags: "Users want this...", "This will reduce churn by...", "The market will wait..."

Challenge with:

• What evidence supports this? Research? Data? Or intuition?
• What if users don't adopt? What's the fallback?
• What are competitors doing in this space?
• How will you know if this assumption is wrong?

5. External Assumptions

Assumptions about factors outside your control.

Red flags: "The vendor will deliver...", "Regulations won't change...", "The market stays stable..."

Challenge with:

• What's the contingency if this doesn't happen?
• What's the vendor's track record on commitments?
• What early warning signs would indicate this is wrong?

Process

Step 1: Surface Assumptions

Read the plan and flag statements treated as facts without validation:

• "We will..." (without evidence)
• "We can..." (without proof)
• "Users want..." (without data)
• "It should..." (without testing)
• "We expect..." (without basis)
• "We assume..." (at least they're honest)

Step 2: Categorize and Assess

For each assumption, determine:

Step 3: Apply Challenge Patterns

For high-risk assumptions, apply these patterns:

Reality Check — Compare to external data:

"You assume [X]. Industry data shows [Y]. What makes you different?"

History Test — Compare to past performance:

"You assume [X]. Last time you attempted [similar], it took [Y]. What changed?"

Stress Test — Push to failure point:

"You assume [X]. What happens when [stress scenario]?"

Dependency Audit — Trace dependencies:

"For [assumption] to be true, what else must also be true?"

Inverse Test — Consider the opposite:

"If [assumption] is wrong, what's the impact? What's Plan B?"

Step 4: Prioritize

Focus on assumptions that are:

1. High impact — project fails if wrong
2. Low evidence — based on hope, not data
3. Testable — can be validated before commitment

Wishful Thinking Indicators

Red flags that suggest hope rather than evidence:

• Optimistic Timeline: "Should only take...", "If we're focused..." — Reality: add 30-50% buffer
• Magical Hiring: "We'll just hire...", "Once we have the team..." — Reality: 3-6 months to hire senior, 2-3 months to productive
• Simple Integration: "It's just an API call...", "Should be straightforward..." — Reality: edge cases, rate limits, surprises always
• Obvious Market: "Everyone needs this...", "Users have been asking..." — Reality: "everyone" is not a segment
• Linear Scaling: "If we can do X, we can do 10X..." — Reality: scaling is non-linear

When to Use This Skill

Use assumption-challenger for surfacing hidden assumptions and stress-testing them with evidence. Use antipattern-detector for recognizing known failure patterns. Both run together in /validate.

Pre-Delivery Checklist

Before presenting an analysis, verify:

• Every assumption includes all 7 table fields (Category, Stated/Implicit, Evidence For, Evidence Against, Risk if Wrong, How to Validate, Verdict)
• "How to Validate" entries are executable actions, not vague suggestions
• Verdicts are assigned (Valid/Questionable/Invalid/Unknown)
• Assumptions are prioritized by impact × uncertainty
• Wishful thinking indicators are flagged with specific quotes

Output Format

# Assumption Analysis: [Plan Name]

## Summary
- **Total Assumptions Identified**: [Count]
- **High-Risk**: [Count] | **Medium-Risk**: [Count] | **Low-Risk**: [Count]

## Critical Assumptions (Must Validate Before Proceeding)

### Assumption: [Statement]
**Category**: [Type] | **Stated or Implicit**: [Which]

**The Problem**: [Why questionable]
**Evidence For**: [Supporting evidence]
**Evidence Against**: [Counter-evidence]
**If Wrong**: Timeline: [impact] | Cost: [impact] | Success: [impact]
**How to Validate**: [Method and cost/time]
**Verdict**: Valid / Questionable / Invalid / Unknown

---

## Medium-Risk Assumptions (Should Validate)
[Brief analysis for each]

## Low-Risk Assumptions (Monitor)
[List]

## Recommendations
### Before Proceeding
1. [Validation action]
### Risk Mitigation
1. [Mitigation for critical assumptions]
### Contingency Plans Needed
1. [Plan B for each critical assumption]