sdd-design

A command that turns written feature requirements into a technical design specification. The design covers architecture, approved technologies, and non-functional needs such as security, speed, and scale.

In plain words
What is it for?
Use it after requirements are written to plan the architecture, data and service boundaries, technologies, security considerations, performance needs, and implementation approach.
Why use it?
It connects what a feature must do with a concrete plan for building it within the project’s existing structure and technology choices.

Command 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 commands/nahisaho/codegraphmcpserver/sdd-design
Clone the repo
git clone --depth 1 https://github.com/nahisaho/CodeGraphMCPServer

Made for: Claude Code.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,746 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 $0.00000 $0.03746
Opus 5 $0.00000 $0.01873
Sonnet 5 $0.00000 $0.00749
Haiku 4.5 $0.00000 $0.00375

Measured 2d ago against content hash c30264e24b15, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sdd-design 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 2d 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/commands/sdd-design.md · 735 lines

How it starts

The opening of the file, as written. The whole thing — 735 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SDD Design Command

Generate technical design from requirements.


Instructions for Claude

You are executing the /sdd-design [feature-name] command to create a technical design specification.

Command Format

/sdd-design authentication
/sdd-design payment-processing
/sdd-design user-dashboard

Your Task

Generate a comprehensive technical design that implements the requirements while adhering to constitutional governance.


Process

1. Read Context (Article VI)

CRITICAL: Read these files BEFORE designing:

# Steering Context
steering/structure.md    # Architecture patterns to follow
steering/tech.md         # Technology stack to use
steering/product.md      # Product goals and users

# Requirements
storage/specs/{{feature-name}}-requirements.md  # What to implement

Extract:

  • Architecture pattern (monolith, microservices, library-first)
  • Approved technologies (languages, frameworks, databases)
  • Requirements to implement
  • Non-functional requirements (performance, security, scale)

2. Verify Requirements Exist

Check if requirements file exists:

If NOT found:

❌ **Requirements file not found**

Expected: storage/specs/{{feature-name}}-requirements.md

Please run `/sdd-requirements {{feature-name}}` first.

Design cannot proceed without requirements (Article V: Traceability).

If found: Proceed with design


3. Generate Design Document

Use template from templates/design.md:

A. Architecture Design (C4 Model)

Create 3 levels of C4 diagrams:

Level 1: Context Diagram

  • Show system in context
  • External users
  • External systems
  • Integration points

Level 2: Container Diagram

  • Major deployable units
  • Databases
  • Message queues
  • External APIs

Level 3: Component Diagram

  • Internal components of main container
  • Controllers, services, repositories
  • Data flow between components

Example:

### C4 Model: Container Diagram

Read the full file on GitHub · 735 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. 2d ago First seen · 735 lines · 0 tokens per session scan A c30264e24b15

Subscribe to this mod's changes

sdd-design is a command published in the GitHub repository nahisaho/CodeGraphMCPServer (12 stars, last pushed 8mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 3,746 tokens. 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.