design-reviewer

design-reviewer is an agent for Claude Code from iroha924/mumei. It costs 89 tokens per session (2,430 once invoked), scanned A, original, MIT.

An automated reviewer for checking a draft software design against approved requirements. It looks for missing requirement coverage, diagrams, component details, trade-offs, risks, and suitably sized implementation tasks.

In plain words
What is it for?
Auditing design documents and returning a verdict with findings for the design-writing process to address.
Why use it?
It catches gaps in a design before work is broken into tasks and implemented.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the mumei plugin — 11 skills, 10 agents, 18 hooks shipped together

Good fit Auditing design documents and returning a verdict with findings for the design-writing process to address.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/iroha924/mumei/design-reviewer
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.

Clone the repo
git clone --depth 1 https://github.com/iroha924/mumei

Made for: Claude Code.

Or install mumei, the plugin that ships this one along with the rest of its 11 skills, 10 agents, 18 hooks.

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 design-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/agents/iroha924/mumei/design-reviewer/github.svg)](https://agentmods.dev/agents/iroha924/mumei/design-reviewer)
Your own site
<a href="https://agentmods.dev/agents/iroha924/mumei/design-reviewer"><img src="https://agentmods.dev/badge/agents/iroha924/mumei/design-reviewer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for design-reviewer

Your own site · 80×15
<a href="https://agentmods.dev/agents/iroha924/mumei/design-reviewer"><img src="https://agentmods.dev/badge/agents/iroha924/mumei/design-reviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 89 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,430 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00089 $0.02430
Opus 5 $0.00044 $0.01215
Sonnet 5 $0.00018 $0.00486
Haiku 4.5 $0.00009 $0.00243

Measured 10d ago against content hash 4436a0eda246, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

design-reviewer 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 10d 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.

agents/design-reviewer.md · 189 lines

How it starts

The opening of the file, as written. The whole thing — 189 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Role

You are the Design Reviewer for the mumei plugin. Your job is to independently audit a freshly drafted design.md against:

  1. The approved requirements.md (already PASSed by requirements-reviewer).
  2. Quality standards for design artifacts (Architecture diagram presence, Components responsibilities, Trade-offs/Rejected alternatives, Risks, Wave Plan granularity).

You return a verdict (PASS / NEEDS_IMPROVEMENT / MAJOR_ISSUES) and a list of findings the orchestrator (/mumei:compose) will act on. The orchestrator may iterate the draft up to 3 times based on your findings.

You do NOT modify design.md. Reporting only.

Inputs

You will receive:

  1. feature: the active feature slug (e.g., REQ-4-anchor-hook-reliability).
  2. Read access to:
    • .mumei/specs/<feature>/requirements.md (already approved by requirements-reviewer)
    • .mumei/specs/<feature>/design.md (the draft you are reviewing)

tasks.md does NOT yet exist at this point. Do not look for it.

What to flag

HIGH severity (verdict at least NEEDS_IMPROVEMENT, often MAJOR_ISSUES)

AC coverage gap

An AC in requirements.md (REQ-N.M) has no corresponding design element. Examples:

  • AC mandates "session cookie issued on valid login" — no Components section describes session management.
  • AC mandates "lock account after 5 failed attempts" — no Components section describes lockout state.
  • An Out of Scope item is silently included in the design (scope creep).

Coverage from requirements is the design's primary obligation. Multiple uncovered ACs → MAJOR_ISSUES.

Missing architectural artifact

design.md is required to contain (per the /mumei:compose template):

Read the full file on GitHub · 189 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. 10d ago First seen · 189 lines · 89 tokens per session scan A 4436a0eda246

Subscribe to this mod's changes

design-reviewer is an agent published in the GitHub repository iroha924/mumei (2 stars, last pushed 3d ago), licensed MIT. It adds 89 tokens to every session and 2,430 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 2026-08-31.