Foundation Sprint Magic Lenses
Try it: /pm-skills:tool-foundation-sprint-magic-lenses "Your context here"
Day 2 afternoon of a Foundation Sprint. The team evaluates each candidate approach from multiple perspectives, surfaces contradictions, and produces a top bet plus a backup plan. The Decider names both; without an explicit backup, invalidation of the top bet sends the team back to ambiguous debate.
Family contract: docs/reference/skill-families/foundation-sprint-skills-contract.md. This skill is a member of foundation-sprint-skills.
When to Use
Section titled “When to Use”- Day 2 afternoon of a Foundation Sprint.
- Approach Options is signed; the team has 3-7 candidate approaches advancing.
- The team has at least 1 team-specific custom lens prepared (per ratified spec decision; classic lenses alone are insufficient).
When NOT to Use
Section titled “When NOT to Use”- Approach Options is unresolved or under-numbered (fewer than 3). Force a third option through the approach-options skill first.
- The team has pre-committed to a top bet. Magic Lenses is a sense-making exercise; if the decision is already made, the time is better spent on Founding Hypothesis.
- The team is exhausted and cannot evaluate clearly. Postpone to Day 2 morning of a follow-up sprint rather than rush.
How to Use
Section titled “How to Use”Invoke the skill by name (/pm-skills:tool-foundation-sprint-magic-lenses on Claude Code, $tool-foundation-sprint-magic-lenses on Codex):
/pm-skills:tool-foundation-sprint-magic-lenses "Your context here"Or reference the skill file directly: skills/tool-foundation-sprint-magic-lenses/SKILL.md
What This Skill Produces
Section titled “What This Skill Produces”A single bundled artifact with six sections:
- Classic lens charts: customer, pragmatic, growth, money lenses each as a 2x2 plot or qualitative position of every approach.
- Custom lens charts: at least 1 team-specific lens (defensibility, mission fit, founder excitement, learning rate, etc.).
- Pattern review: consistent winners across lenses, contradictions, biggest trade-off the team is making.
- Top bet: the Decider’s chosen approach with rationale.
- Backup plan: the runner-up approach the team falls back to if the top bet invalidates.
- Decision rationale: one paragraph explaining why the top bet over the backup.
See references/TEMPLATE.md for the canonical structure and references/EXAMPLE.md for the Brainshelf example.
The Five Canonical Lenses
Section titled “The Five Canonical Lenses”| Lens | What it asks | Why it matters |
|---|---|---|
| Customer | Which approach do target customers immediately understand and want? | If customers don’t get it, nothing else matters |
| Pragmatic | Which approach can the team ship at quality in [build window]? | Beautiful approaches the team can’t ship are not real options |
| Growth | Which approach gives the team a story strong enough to acquire users without paid channels? | Friction at the door tells you about word-of-mouth potential |
| Money | Which approach has the cleanest path to a paying customer? | Strategic clarity must include the revenue path |
| Custom (1+ required) | Team-specific lens that captures what would otherwise be missed | Each team has a unique constraint or opportunity worth a dedicated view |
Custom lens examples: defensibility against a specific competitor, founder excitement, mission fit, learning rate, regulatory risk, partner alignment, hiring leverage.
Sequence (105 minutes)
Section titled “Sequence (105 minutes)”Step 1: Frame the lenses (5 min)
Section titled “Step 1: Frame the lenses (5 min)”Facilitator restates the 4 classic lenses and confirms the 1 or more custom lenses the team prepared. If no custom lens is prepared, this skill prompts the team to generate one before proceeding (per ratified spec decision).
Step 2: Score each approach per lens (40-60 min)
Section titled “Step 2: Score each approach per lens (40-60 min)”For each lens, plot each approach on a 2x2 of (high/low value on that lens) by (high/low feasibility for that lens). Use dot positions rather than numeric scores; arbitrary precision (3.7 vs 3.8) is a smell that the team has confused sense-making with math.
The team discusses each lens briefly before plotting. Decider does not vote in this step; the Decider supervotes at the end.
Step 3: Pattern review (15-25 min)
Section titled “Step 3: Pattern review (15-25 min)”After all lenses are plotted, the team identifies:
- Consistent winners: approaches that score in the top half of 3 or more lenses.
- Consistent losers: approaches that score in the bottom half of 3 or more lenses. These drop out.
- Contradictions: approaches that win one lens hard but lose another. These surface the trade-offs the Decider must make.
- Biggest trade-off: name it explicitly. “Boring-and-shippable vs risky-and-distinctive.” “Mass-market vs niche-defensible.” Naming the trade-off prevents the Decider from picking by vibes.
Step 4: Decider supervote on top bet (10-15 min)
Section titled “Step 4: Decider supervote on top bet (10-15 min)”The Decider names the top bet. The chosen approach should be:
- A consistent winner OR a contradictory approach the Decider explicitly chooses to take the bet on.
- Defensible in language (“we are betting [trade-off] because [reason]”).
- Aligned with the Mini Manifesto from Day 1.
Step 5: Decider names backup plan (5-10 min)
Section titled “Step 5: Decider names backup plan (5-10 min)”The Decider names the backup. The backup is NOT a second-place approach to soothe whoever advocated for it; it is the approach the team will pivot to if the top bet fails validation. The backup MUST be distinct from the top bet in strategic direction.
If the top bet and backup are too similar, the Decider has not named a real backup. The skill prompts for a more distinct alternative.
Step 6: Decision rationale (5-10 min)
Section titled “Step 6: Decision rationale (5-10 min)”The Decider authors one paragraph explaining why this top bet over this backup. The rationale will become the spine of the Founding Hypothesis’s “why we believe this” section.
Common Pitfalls
Section titled “Common Pitfalls”- Treating lens scoring as mathematical truth. Lenses are sense-making tools; if the team argues about whether an approach scores 3.7 or 3.8 on a lens, the team has lost the plot.
- Skipping the custom lens. The 4 classic lenses are generic by design. The custom lens is where the team’s specific situation shows up; skipping it produces a generic top bet.
- Falling in love with the top bet. Confidence after Magic Lenses should be calibrated, not high. The next skill, Founding Hypothesis, asks “what could prove us wrong”; the team that has fallen in love with the top bet cannot answer that question honestly.
- Skipping the backup plan. Without an explicit backup, invalidation sends the team back to ambiguous debate. The backup forces the team to acknowledge that the top bet might fail.
- Backup that is too similar to top bet. “Approach Yellow with one feature added” is not a backup; it’s an iteration. Backup must be a different strategic direction.
- Decider names top bet by enthusiasm, not by analysis. The pattern review exists to give the Decider a structured basis for the call. If the Decider picks before the pattern review, the skill provided no value.
Decider Role
Section titled “Decider Role”The Decider’s job during Magic Lenses:
- Listen during lens scoring without telegraphing preferences.
- Engage during pattern review to surface the trade-off explicitly.
- Supervote the top bet with rationale.
- Name the backup plan as a distinct strategic direction.
- Author the one-paragraph decision rationale.
Canonical Sources
Section titled “Canonical Sources”- Character Capital. “Foundation Sprint guide.” Magic Lenses section and lens definitions.
- Knapp, J., and Zeratsky, J. Click. Day 2 afternoon sequence.
- Knapp, J., and Zeratsky, J. “Introducing the Foundation Sprint.” Lenny’s Newsletter. Magic Lenses section.
Cross-Skill Usage
Section titled “Cross-Skill Usage”Prerequisites: tool-foundation-sprint-approach-options. The approach set is the load-bearing input.
The skill invokes tool-note-and-vote at least once (for the top bet supervote when scoring is ambiguous). Additional invocations may happen for the custom lens definition if the team has not pre-prepared one.
Next invocation: tool-foundation-sprint-founding-hypothesis at Day 2 end. The top bet, the backup, and the decision rationale flow directly into the Founding Hypothesis template.
Decider Checkpoint
Section titled “Decider Checkpoint”This skill ends with a Decider Checkpoint in references/TEMPLATE.md. The Decider signs off on the top bet, the backup, and the decision rationale. Without sign-off, Founding Hypothesis cannot start cleanly.
Output Template
Section titled “Output Template”Foundation Sprint Magic Lenses: [Initiative name] (Day 2 Afternoon)
Section titled “Foundation Sprint Magic Lenses: [Initiative name] (Day 2 Afternoon)”Approach labels: [List the 3-7 approaches from Approach Options with their labels.]
Customer Lens
Section titled “Customer Lens”Question: Which approach do target customers immediately understand and want?
| Approach | Customer perception | Position |
|---|---|---|
| [Label 1] | [Brief reaction] | [HV-HF / HV-LF / LV-HF / LV-LF] |
| [Label 2] | [Brief reaction] | [position] |
| [Label 3] | [Brief reaction] | [position] |
Top per Customer Lens: [Approach label(s)]
Pragmatic Lens
Section titled “Pragmatic Lens”Question: Which approach can the team ship at quality in the build window?
| Approach | Build cost | Risk |
|---|---|---|
| [Label 1] | [Low / Medium / High] | [Low / Medium / High] |
| [Label 2] | […] | […] |
Top per Pragmatic Lens: [Approach label(s)]
Growth Lens
Section titled “Growth Lens”Question: Which approach gives the team a story strong enough to acquire users without paid channels?
| Approach | Why people would tell a friend |
|---|---|
| [Label 1] | [One-line word-of-mouth story] |
| [Label 2] | […] |
Top per Growth Lens: [Approach label(s)]
Money Lens
Section titled “Money Lens”Question: Which approach has the cleanest path to a paying customer?
| Approach | Monetization story |
|---|---|
| [Label 1] | [Path to revenue] |
| [Label 2] | […] |
Top per Money Lens: [Approach label(s)]
Custom Lens [N]: [Name]
Section titled “Custom Lens [N]: [Name]”Question: [The lens-specific question the team needs answered.]
| Approach | [Lens-specific dimension] |
|---|---|
| [Label 1] | [Assessment] |
| [Label 2] | […] |
Top per [Custom Lens]: [Approach label(s)]
[Add additional custom lenses as needed. Minimum 1 custom lens required.]
Pattern Review
Section titled “Pattern Review”Consistent winners: [Approaches that scored top half of 3+ lenses.]
Consistent losers (eliminated):
- Label: [Why this approach drops out.]
Contradictions:
- [Contradiction pattern]: [Which approaches win one lens hard but lose another?]
Biggest trade-off: [Name it explicitly. The Decider’s choice is along this axis.]
Top Bet (Decider Supervote)
Section titled “Top Bet (Decider Supervote)”Top bet: [Approach label and name].
Rationale: [Two or three sentences naming the trade-off the Decider is taking. Should be defensible in language.]
Backup Plan
Section titled “Backup Plan”Backup: [Distinct approach label and name].
[One paragraph explaining when the team falls back to this. The backup MUST be strategically distinct from the top bet, not an iteration of it.]
Decision Rationale
Section titled “Decision Rationale”[One paragraph explaining why this top bet over this backup. This paragraph becomes the spine of the Founding Hypothesis’s “why we believe this” section.]
Decider Checkpoint
Section titled “Decider Checkpoint”Decider sign-off required before Founding Hypothesis writing begins.
- Decider names the top bet with explicit rationale.
- Decider names the backup as a distinct strategic direction (not an iteration).
- Decider commits to testing the top bet via the planned next step (Design Sprint, customer research, experiment).
- Decider acknowledges the trade-off being taken; the team agrees that re-litigation requires invalidation evidence, not preference shifts.
Signed: [Decider name, role], [ISO date and local time]
Example Output
Section titled “Example Output”Foundation Sprint Magic Lenses: Brainshelf (Day 2 Afternoon)
Foundation Sprint Magic Lenses: Brainshelf (Day 2 Afternoon)
Section titled “Foundation Sprint Magic Lenses: Brainshelf (Day 2 Afternoon)”The Brainshelf team’s Day 2 PM lens evaluation. Top bet and backup named.
Approach labels: A=Yellow Camera, B=Blue Library, C=Green Voice, D=Red Bookstore, E=Purple Triage.
Customer Lens
Section titled “Customer Lens”Question: Which approach do target customers immediately understand and want?
| Approach | Customer perception | Position |
|---|---|---|
| Yellow Camera | ”I get it. Point and capture.” | HV-HF (high value, high feasibility) |
| Blue Library | ”Pretty. But I don’t have books to put in it yet.” | MV-HF (medium value, chicken-and-egg) |
| Green Voice | ”Cool, but I talk to my phone in public?” | MV-LF (mixed appetite) |
| Red Bookstore | ”Wait, you do that?” (delight) | VHV-LF (very high value, narrow context) |
| Purple Triage | ”Like Pocket for books. Sure.” | MV-HF (low novelty) |
Top per Customer Lens: Yellow (broad), Red (deep delight).
Pragmatic Lens
Section titled “Pragmatic Lens”Question: Which approach can the team realistically ship at quality in 8-10 weeks?
| Approach | Build cost | Risk |
|---|---|---|
| Yellow Camera | Medium (OCR + cover-recognition; Apple Vision API available) | Acceptable |
| Blue Library | Low (CRUD + UI polish) | Low |
| Green Voice | High (voice quality + book entity resolution) | High |
| Red Bookstore | High (geofence + offline book DB) | Very high |
| Purple Triage | Low-medium (share extension + queue UI) | Low |
Top per Pragmatic Lens: Blue, Yellow.
Growth Lens
Section titled “Growth Lens”Question: Which approach gives the team a story strong enough to acquire users without paid channels?
| Approach | Why people would tell a friend |
|---|---|
| Yellow Camera | ”I just snap books, it’s the easiest tracker I’ve used.” Decent. |
| Blue Library | ”My library looks nice.” Low signal. |
| Green Voice | ”I talk to it and it just works.” High novelty IF it works. |
| Red Bookstore | ”It tells me at the bookstore if I’ve already read it.” Highest novelty. |
| Purple Triage | ”Pocket for books.” Low novelty. |
Top per Growth Lens: Red, Green (if voice quality holds), Yellow.
Money Lens
Section titled “Money Lens”Question: Which approach has the cleanest path to a paying customer?
| Approach | Monetization story |
|---|---|
| Yellow Camera | Free tier with limit; paid sync + cross-device. Familiar. |
| Blue Library | Same as Yellow; library-as-portfolio enables aesthetic premium. |
| Green Voice | Same as Yellow; voice is a free differentiator, not a paywall. |
| Red Bookstore | Bookstore mode could be a premium feature (geofence intelligence). |
| Purple Triage | Triage capacity could tier (10 / 50 / unlimited). Pocket precedent. |
Top per Money Lens: All approaches have similar models. Slight edge to Blue (visual library could be a premium aesthetic) and Red (premium context awareness).
Custom Lens 1: Defensibility Against Goodreads / Amazon
Section titled “Custom Lens 1: Defensibility Against Goodreads / Amazon”Question: If Goodreads decided to copy this in 6 months, which approach would still feel different?
| Approach | Defensible? |
|---|---|
| Yellow Camera | No. Goodreads has cover scanning today. |
| Blue Library | Partially. Brainshelf’s principles (private, no feed) make this strategically distinct. |
| Green Voice | Yes. Goodreads is unlikely to commit to voice; mobile-app-first companies dominate. |
| Red Bookstore | Yes. Goodreads is owned by Amazon; geofencing physical bookstores is awkward for them. |
| Purple Triage | Partially. The triage pattern is well-known. |
Top per Defensibility Lens: Red, Green.
Pattern Review
Section titled “Pattern Review”Consistent winners: Yellow Camera (positive on 4 of 5 lenses), Red Bookstore (positive on 4 of 5 lenses).
Consistent losers (eliminated):
- Blue Library: chicken-and-egg problem (empty library at launch); not strong enough on its own.
- Green Voice: feasibility risk too high for the differentiation it provides; voice can be a feature inside another approach later.
- Purple Triage: doesn’t carry the “did I read this?” recall pain hard enough.
Contradictions:
- Red is high on Customer + Growth + Money + Defensibility but failing Pragmatic. Hardest to ship; highest leverage if shipped.
- Yellow is positive across all five but never #1 on any single lens. Strong consistent middle.
Biggest trade-off: Boring-and-shippable (Yellow) versus risky-and-distinctive (Red).
Top Bet (Decider Supervote)
Section titled “Top Bet (Decider Supervote)”Top bet: Approach A (Yellow Camera-First Capture).
Rationale: The riskiest assumption for Brainshelf is not “is this concept appealing” (Red would tell us that). The riskiest assumption is “will people switch from doing nothing to using a tracking app at all if friction drops below 3 seconds?” Yellow tests that hypothesis most directly. If Yellow succeeds, Red becomes a Phase 2 differentiator. If Yellow fails (people don’t capture even with no friction), Red doesn’t save the product.
Backup Plan
Section titled “Backup Plan”Backup: Approach D (Red Bookstore Mode).
If the Design Sprint test of Yellow shows weak adoption (“customers nod but don’t actually capture”), Brainshelf pivots to lead with bookstore-mode delight. Recall-at-context becomes the wedge, capture follows. This is a strategically distinct direction (context-driven recall) not an iteration of Yellow.
Decision Rationale
Section titled “Decision Rationale”The team converged on Yellow over Red because the test value of Yellow is higher. Validating the core capture-speed differentiator early de-risks every downstream investment. Red is more delightful but tests a narrower (and later) part of the product. Better to know if the foundation works first.
Decider Checkpoint
Section titled “Decider Checkpoint”Decider sign-off required before Founding Hypothesis writing begins.
- Jamie names Yellow (Camera-First Capture) as the top bet.
- Jamie names Red (Bookstore Mode) as the backup, strategically distinct from Yellow.
- Jamie commits to NOT building Yellow as a Camera with Red features grafted on. They are distinct approaches with distinct testing paths.
- Jamie agrees to test the Yellow top bet via the planned Design Sprint week of May 26.
Signed: Jamie (founder, PM), 2026-05-14 15:40 PT