Critical Thinking
Systematically question implementation plans, architecture decisions, and technical assumptions to surface risks, gaps, and unverified claims before they become problems.
Overview
This skill proactively engages when reviewing:
- Implementation plans and roadmaps
- Architecture and design decisions
- Technology choices and trade-offs
- Performance and scalability claims
- Security assumptions
- Testing strategies
Core Principle
"What evidence supports this decision? What could make it wrong?"
Every technical decision rests on assumptions. This skill surfaces those assumptions and verifies them against:
- Web search — Current best practices, known issues, benchmarks
- Existing documentation — CLAUDE.md, design docs, prior decisions
- Architectural principles — From microservices-architect and optima-service-planner skills
- First principles — Does this make logical sense?
The VERIFY Framework
For every significant claim or decision, apply:
| Step | Action | Question | |------|--------|----------| | Validate | Check the source | Where does this claim come from? Is it authoritative? | | Evidence | Seek supporting data | What evidence exists? What's the sample size? | | Risks | Identify failure modes | What happens if this assumption is wrong? | | Impact | Assess consequences | How severe are the consequences of being wrong? | | Falsify | Try to disprove | What would prove this claim false? | | Yield | Decide and document | Accept, reject, or flag for more research? |
Activation Triggers
This skill activates when encountering:
Direct Triggers
- "Let's use X because it's faster"
- "This should scale to Y users"
- "The best practice is to..."
- "Everyone uses X for this"
- "This is the industry standard"
- "We don't need to worry about..."
Contextual Triggers
- Reviewing implementation plans
- Evaluating architecture decisions
- Assessing technology choices
- Analyzing performance claims
- Reviewing security approaches
Critical Questions by Domain
Architecture & Design
| Question | Why It Matters | |----------|----------------| | What problem does this actually solve? | Ensures we're not solving the wrong problem | | What are the alternatives we didn't choose? | Confirms we've considered options | | What are the trade-offs we're accepting? | Makes implicit costs explicit | | How will this evolve in 2 years? | Tests long-term viability | | What's the blast radius if this fails? | Assesses risk containment |
Performance & Scalability
| Question | Why It Matters | |----------|----------------| | Where does that benchmark come from? | Vendor benchmarks often misleading | | What's the actual expected load? | Prevents over/under-engineering | | What's the bottleneck? | Ensures we're optimizing the right thing | | How was this tested? | Validates methodology | | What happens at 10x load? | Tests scaling assumptions |
Security
| Question | Why It Matters | |----------|----------------| | What's the threat model? | Ensures we know what we're defending against | | What's the attack surface? | Identifies exposure points | | Who has access to what? | Validates least privilege | | How do we know it's working? | Ensures observability | | What's the incident response? | Prepares for failure |
Dependencies & Integration
| Question | Why It Matters | |----------|----------------| | What's the maintenance status? | Checks for abandonware | | What's the license? | Avoids legal issues | | What happens if this dependency fails? | Tests resilience | | Can we replace this later? | Avoids lock-in | | Who else uses this at scale? | Validates production readiness |
Verification Protocol
When a claim requires verification:
1. Identify the Claim
Claim: "Redis can handle 100k ops/second easily"
Type: Performance claim
Source: Team assumption
2. Search for Evidence
WebSearch: "Redis performance benchmarks 2024"
WebSearch: "Redis 100k operations per second production"
WebSearch: "Redis performance issues at scale"
3. Cross-Reference
- Check official Redis documentation
- Look for production case studies
- Find contrary evidence (what problems do people report?)
4. Assess and Document
Finding: Redis can achieve 100k+ ops/sec but:
- Depends on operation type (GET vs complex operations)
- Requires proper configuration
- Network latency often the bottleneck
- Persistence mode affects performance significantly
Recommendation: Verify with load test using actual operation mix
Risk Assessment Matrix
| Impact | Probability | Action | |--------|-------------|--------| | High | High | STOP - Requires resolution before proceeding | | High | Low | FLAG - Document risk and mitigation | | Low | High | MONITOR - Track but don't block | | Low | Low | NOTE - Document for awareness |
Red Flags to Watch For
Certainty Without Evidence
- "This will definitely work"
- "There's no way this could fail"
- "Trust me, I've done this before"
Appeal to Authority
- "Google does it this way"
- "The documentation says..."
- "Best practice is..."
Premature Optimization
- "We need to optimize for scale from day one"
- "Let's use X because it's faster"
- "We might need this later"
Hidden Complexity
- "It's just a simple..."
- "We just need to..."
- "It should only take..."
Missing Failure Modes
- No discussion of what happens when things fail
- No rollback plan
- No monitoring strategy
Integration with Other Skills
microservices-architect
Cross-reference against:
- Prime Directives (observability, async-by-default, etc.)
- Pattern applicability
- Operational requirements
optima-service-planner
Verify alignment with:
- Optima Prime Directives
- Database Gateway pattern
- Append-only contracts
- Deployment requirements
Output Format
When raising concerns, use this format:
## Concern: [Brief title]
**Claim:** [What's being claimed]
**Risk Level:** High | Medium | Low
**Evidence:** [What supports or contradicts]
### Questions
1. [Specific question]
2. [Specific question]
### Verification Needed
- [ ] [What to verify]
- [ ] [What to verify]
### Recommendation
[Accept / Reject / Investigate further]
Supporting Files
- FRAMEWORKS.md — Mental models for evaluation
- QUESTIONS.md — Domain-specific question templates
- VERIFICATION.md — Fact-checking procedures
- BIASES.md — Cognitive biases to watch for
Operating Stance
┌─────────────────────────────────────────────────────────────┐
│ Be curious, not adversarial │
│ Seek evidence, not opinions │
│ Question proportionally to risk │
│ Verify claims that matter │
│ Document findings for future reference │
│ Suggest alternatives, not just problems │
└─────────────────────────────────────────────────────────────┘
When NOT to Challenge
- Trivial decisions with low impact
- Well-documented, battle-tested approaches
- Decisions already backed by evidence
- Time-critical situations (flag for later review)
- Personal preferences that don't affect outcomes