/tool-design-sprint-prototype-plan

name: tool-design-sprint-prototype-plan
description: Day 4 (Thursday) move of a Design Sprint that produces the planning artifact for the day. Output covers the prototype role plan (Maker, Stitcher, Writer, Asset Collector, Interviewer), prototype brief (what to build, fidelity bar, time allocation per role), canonical Five-Act Interview script (Welcome, Context, Intro, Tasks, Debrief), trial-run checklist, and Friday participant confirmation tracker. The actual prototype build is craft work outside the skill's AI invocation surface. Use Thursday morning after Wednesday's storyboard is signed off.
license: Apache-2.0
metadata:
  classification: tool
  version: "1.0.0"
  updated: 2026-07-04
  tool: design-sprint
  move: prototype-plan
  category: discovery
  frameworks:
    - design-sprint
    - sprint
  timebox_minutes: 90
  roles:
    - facilitator
    - design
    - engineering
    - researcher
    - pm
  prerequisites:
    - tool-design-sprint-decide-and-storyboard
  inputs:
    - storyboard (from Wednesday)
    - sprint questions (from Monday)
    - founding hypothesis (optional; from a prior Foundation Sprint)
    - prototype medium choice (from the brief)
  outputs:
    - prototype role plan
    - prototype brief
    - interview script (Five-Act)
    - trial-run checklist
    - participant confirmation tracker
  author: product-on-purpose

<!-- PM-Skills | https://github.com/product-on-purpose/pm-skills | Apache 2.0 -->

Design Sprint Prototype Plan (Thursday morning)

Thursday is the prototype build day. This skill produces the morning planning artifact that makes the build run; it does NOT build the prototype itself. The skill assigns roles, locks the fidelity bar, drafts the Five-Act interview script, defines the trial-run gate, and confirms Friday participants. The actual building (Figma frames, slideware decks, role-play scripts, paper assemblies) is craft work the team owns through the rest of Thursday.

Family contract: [`docs/reference/skill-families/design-sprint-skills-contract.md`](../../docs/reference/skill-families/design-sprint-skills-contract.md). This skill is a member of `design-sprint-skills`.

When to Use

• It is Thursday morning of the Design Sprint and Wednesday's storyboard is signed off.
• The Friday participant tracker needs a Thursday-morning confirmation check; cancellations now trigger buffer activation.
• The interview script needs to be drafted (or refined from a prior sprint's template) before the interviewer can mock-run it Thursday afternoon.
• The team needs role assignments before parallel build work begins; ad-hoc assignment Thursday afternoon wastes 1-2 hours.

When NOT to Use

• Wednesday is not closed. Return to `tool-design-sprint-decide-and-storyboard`; without a locked storyboard, the prototype has no spec.
• The team is trying to use this skill to build the prototype. The prototype is craft work (per Ratified Decision 1 in the DS integration plan). This skill plans Thursday; the build happens in Figma, Keynote, paper, or whatever the medium is.
• The team has decided to skip Friday's trial run. Trial run is the gate that catches "prototype is unreachable" or "interview script confuses customer" before live interviews start. Skipping it converts Friday into a debugging session.
• Friday participant cancellations have triggered cohort-shrinks-to-fewer-than-4. Pause the sprint and decide whether to postpone Friday or accept a reduced-evidence test.

What This Skill Produces

A single bundled artifact with five sections:

1. **Prototype role plan**: assigns 5 canonical roles (Maker, Stitcher, Writer, Asset Collector, Interviewer) across the team. Roles can double up on small teams; cannot triple up except for Asset Collector. 2. **Prototype brief**: one-page spec covering what to build (storyboard panels in scope), fidelity bar (what "real enough" means for the medium), time allocation per role, and what's explicitly NOT being built. 3. **Interview script (Five-Act)**: canonical Five-Act structure (Welcome, Context, Intro, Tasks, Debrief) with team-supplied task wording derived from the storyboard. The act sequence is fixed; only Tasks is heavily customized. 4. **Trial-run checklist**: the gates the prototype must pass Thursday afternoon (canonically 16:00-17:00) before Friday begins. Each gate is a yes/no item the interviewer or Maker confirms. 5. **Participant confirmation tracker**: Thursday morning re-confirmation of all 5 Friday slots; cancellations trigger buffer-slot activation; failures cascade to a cohort-decision moment.

See `references/TEMPLATE.md` for the canonical structure and `references/EXAMPLE.md` for the Brainshelf book-catalog Thursday morning artifact.

Five Canonical Roles

Sprint book Chapter 16 defines these 5 roles. The skill assigns them; the humans fill them.

| Role | What they do | Typical owner | |---|---|---| | Maker | Builds the prototype surface (Figma frames, Keynote slides, role-play props). Owns visual and interaction work. | Design lead | | Stitcher | Connects the Maker's surfaces into a coherent end-to-end flow (Figma interactions, Keynote transitions, role-play sequence). | Design lead OR engineering lead | | Writer | Writes prototype copy (button labels, body text, error states, microcopy). Critical for credibility; bad copy breaks trust. | PM OR researcher | | Asset Collector | Sources images, icons, sample data (book covers, names, dates, fake-but-believable data). | Anyone with free hands; often whoever isn't on the critical path. | | Interviewer | Runs Friday's interviews. Spends Thursday afternoon drafting and mock-running the Five-Act script. | Researcher OR PM with interview experience. |

On a 4-person team, Maker and Stitcher typically merge (one design owner); Writer and Asset Collector can merge; Interviewer is always a dedicated role.

Five-Act Interview Structure

Canonical structure from Sprint book Chapter 17. The act sequence is fixed; the Tasks act is heavily cus