system-design-skill

system-design-skill

A Claude Code plugin marketplace hosting the system-design-skill plugin: a structured system design interview that turns a rough software idea into a complete, installable Claude skill capturing everything needed to build it.

Repo layout

.claude-plugin/
  marketplace.json                    # marketplace manifest (this repo as a marketplace)
plugins/
  system-design-skill/
    .claude-plugin/
      plugin.json                     # plugin manifest
    skills/
      system-design-interview/        # the skill itself
        SKILL.md
        references/
          interview-phases.md
          question-banks.md
          tech-decisions.md
          non-functional-checklist.md
          implementation-guidance.md
          output-template.md

What it does

Adapted from the Hello Interview system design framework, but tuned for real-world building rather than interview performance. When triggered, the skill runs a focused conversation covering:

1. Context & goals
2. Functional requirements
3. Non-functional requirements
4. Capacity & scale
5. Core entities
6. API / interface
7. Data model
8. Architecture (incl. LLD bridge: domain classes + seed correctness expectations)
9. Deep dives
10. Build plan (acceptance criteria as concrete given/when/then conditions)
11. Decisions & open questions

The output is a new Claude skill (a directory with its own SKILL.md and references) that future Claude sessions can load to continue building the project with full context.

It defaults to the simplest architecture that meets requirements — no reaching for Kafka on a 100-user app — and enforces a correctness-tests-first rule for LLD: before implementing any non-trivial class or service, the test list (happy path, edge cases, error modes, invariants) is written down.

Installing

As a Claude Code plugin (recommended)

Add the marketplace, then install the plugin:

/plugin marketplace add tylerpayne/system-design-skill
/plugin install system-design-skill@tylerpayne

Or from the CLI:

claude plugin marketplace add tylerpayne/system-design-skill
claude plugin install system-design-skill@tylerpayne

The skill is invoked by trigger phrases (see below) or explicitly via /system-design-skill:system-design-interview.

Manual install (no plugin system)

Copy the skill directory into a Claude skills location:

• User-level (all projects): ~/.claude/skills/system-design-interview/
• Project-level: .claude/skills/system-design-interview/ inside your repo

cp -r plugins/system-design-skill/skills/system-design-interview ~/.claude/skills/

Claude Code picks up skills automatically from either location.

Using it

Trigger phrases include:

• "I want to build [an app / service / tool]"
• "Help me design [X]"
• "How should I architect [Y]"

The skill will ask one question at a time, recommend concrete choices with rationale, sketch the most important domain classes with seed invariants and edge cases, and produce an installable skill at the end.

Adding more plugins to this marketplace

To add another plugin to this marketplace:

1. Create plugins/<new-plugin>/.claude-plugin/plugin.json and a sibling skills/<skill>/, commands/, agents/, etc. as needed
2. Add an entry to .claude-plugin/marketplace.json under plugins:

   { "name": "new-plugin", "source": "./plugins/new-plugin", "description": "..." }
   

See the Claude Code plugin marketplace docs for the full schema.