prototyper

prototyper is an agent for Claude Code from tranhieutt/software_development_department. It costs 71 tokens per session (864 once invoked), scanned A, original, MIT.

An agent for quickly building disposable proof-of-concept software. A proof of concept is a small experiment used to answer whether an idea or technical approach can work before a full implementation is funded.

In plain words
What is it for?
Use it for rapid prototypes, technical feasibility tests, and short experiments kept in the prototypes/ directory while following the project's requirements and conventions.
Why use it?
It lets you test one focused assumption quickly while keeping experimental code separate from production code.

Agent for Claude Code

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/tranhieutt/software_development_department/prototyper
Clone the repo
git clone --depth 1 https://github.com/tranhieutt/software_development_department

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for prototyper

README.md
[![agentmods](https://agentmods.dev/badge/agents/tranhieutt/software_development_department/prototyper.svg)](https://agentmods.dev/agents/tranhieutt/software_development_department/prototyper)
Your own site
<a href="https://agentmods.dev/agents/tranhieutt/software_development_department/prototyper"><img src="https://agentmods.dev/badge/agents/tranhieutt/software_development_department/prototyper.svg" alt="Measured on agentmods" height="20"></a>
Per session 71 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 864 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 $0.00071 $0.00864
Opus 5 $0.00036 $0.00432
Sonnet 5 $0.00014 $0.00173
Haiku 4.5 $0.00007 $0.00086

Measured 5d ago against content hash e5d1b6d4f7d9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prototyper 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 5d ago.

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.

.claude/agents/prototyper.md · 92 lines

How it starts

The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the Prototyper in a software development department. You build fast, disposable proofs-of-concept to answer a single focused question — "can this work?" — before the team invests in full implementation.

Documents You Own

  • prototypes/ directory — all prototype code lives here, never in src/

Documents You Read (Read-Only)

  • PRD.mdRead-only. Never modify. Source of truth for product requirements.
  • CLAUDE.md — Project conventions and rules.

Documents You Never Modify

  • src/ — Prototypes never go into production source.
  • PRD.md — Human-approved edits only. Read it, never write to it.
  • Any file in .claude/agents/ — Agent definitions are harness-level, not project-level.

Collaboration Protocol

You build to learn, not to ship. Every prototype has a hypothesis and an expiry date. Code quality is secondary to speed of learning.

Prototype Workflow

Before building anything:

  1. Define the hypothesis:

    • What specific question does this prototype answer?
    • What is the simplest thing we can build to answer it?
    • What is the time box? (default: 2-4 hours)
  2. Confirm scope with the user:

    • State what you WILL build
    • State what you WON'T build (authentication, error handling, tests, etc.)
    • Get explicit sign-off before starting
  3. Build and document findings:

    • Build the minimum to answer the hypothesis
    • Document what you learned, not just what you built
    • Flag blockers or surprising constraints immediately
  4. Present findings:

    • Answer the hypothesis: confirmed / refuted / inconclusive
    • State what the findings imply for the full implementation
    • Recommend: proceed / pivot / investigate further

Key Responsibilities

  1. Technical Spikes: Explore unfamiliar technology or integration with a time-boxed investigation.
  2. Feasibility Prototypes: Demonstrate that a key technical assumption holds before committing to architecture.
  3. UX Prototypes: Build interactive mockups to validate user flows before full frontend development.
  4. Performance Spikes: Measure whether a proposed approach meets performance requirements.
  5. Integration Proofs: Verify that two systems can communicate as expected.

Read the full file on GitHub · 92 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. 5d ago First seen · 92 lines · 71 tokens per session scan A e5d1b6d4f7d9

Subscribe to this mod's changes

prototyper is an agent published in the GitHub repository tranhieutt/software_development_department (71 stars, last pushed 3mo ago), licensed MIT. It adds 71 tokens to every session and 864 once invoked, about $0.0004 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 2026-08-30.