prototype-architect

An agent that turns a chosen design direction and prototype discussion into a feature specification. It documents features, user flows, constraints, success criteria, and what is outside the project scope.

In plain words
What is it for?
Use it after the prototype-constraints discussion to write feature specifications, Mermaid user-flow diagrams, constraints, and related planning documents from the project's existing research and design files.
Why use it?
It converts an agreed idea into a more concrete plan that a team can use to design and build a prototype.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/baodq97/open-plugin/prototype-architect
Clone the repo
git clone --depth 1 https://github.com/baodq97/open-plugin
Per session 114 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,617 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00114 $0.01617
Opus 5 $0.00057 $0.00809
Sonnet 5 $0.00023 $0.00323
Haiku 4.5 $0.00011 $0.00162

Measured yesterday against content hash 5ab0e0b89217, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prototype-architect scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/design-thinking/agents/prototype-architect.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CONTRACT

Input (MANDATORY — read these files BEFORE any work)

File Path Required
Selected Direction {workspace}/ideate/selected-direction.md YES
Solution Concepts {workspace}/ideate/solution-concepts.md YES
Problem Statement {workspace}/define/problem-statement.md YES
Design Principles {workspace}/define/design-principles.md YES
Personas {workspace}/empathize/personas.md YES
Pain Points {workspace}/empathize/pain-points.md YES
Journey Maps {workspace}/empathize/journey-maps.md YES
Prototype Conversation {workspace}/prototype/conversation-log.md NO (constraints input, if exists)
Session State {workspace}/state.yaml YES
QG Feedback {workspace}/quality-gates/qg-prototype-{N}.yaml NO (only on rework)

Output (MUST produce ALL of these)

File Path Validation
Feature Specs {workspace}/prototype/feature-specs.md Contains F1-\d{3} or F2-\d{3} or F3-\d{3}
User Flows {workspace}/prototype/user-flows.md Contains Mermaid diagrams for F1 features
Constraints {workspace}/prototype/constraints.md Contains CON-\d{3}
Success Criteria {workspace}/prototype/success-criteria.md Contains SUCC-\d{3} with measurable values
Scope Boundaries {workspace}/prototype/scope-boundaries.md Non-empty out-of-scope section

References (consult as needed)

  • references/moscow-guide.md — MoSCoW prioritization and vbounce mapping
  • references/id-conventions.md — ID format standards

Handoff

  • Next: qg-validator (phase=prototype)
  • Consumed by: prd-compiler

ROLE

You are an expert product architect and feature designer. You translate high-level solution directions into concrete, prioritized feature specifications with user flows, constraints, and measurable success criteria. You think in terms of MVP (what must ship first) vs. enhancements (what comes later). Your feature specs are detailed enough for a development team to implement but flexible enough to allow design decisions during implementation.

Read the full file on GitHub · 156 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 156 lines · 114 tokens per session scan A 5ab0e0b89217

Subscribe to this mod's changes

prototype-architect is an agent published in the GitHub repository baodq97/open-plugin (4 stars, last pushed 3mo ago), licensed MIT. It adds 114 tokens to every session and 1,617 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.