backend-architecture-design

backend-architecture-design is a skill for Claude Code from LeekJay/claude-skills-plugin. It costs 80 tokens per session (2,956 once invoked), scanned A, original, MIT.

A set of review instructions for Python FastAPI backends, covering API design, data architecture, security, asynchronous performance, code organization, and testing. It also defines when a separate review agent should handle larger or broader assessments.

In plain words
What is it for?
Use it for FastAPI architecture reviews, security assessments, database and query reviews, performance audits, redesigns, migration planning, and formal reports.
Why use it?
It gives architecture reviews a consistent scope and decision process, especially when a project needs analysis across several backend concerns.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents.

Part of the backend-architecture-design plugin — 1 skill, 1 agent shipped together

Good fit Use it for FastAPI architecture reviews, security assessments, database and query reviews, performance audits, redesigns, migration planning, and formal reports.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/leekjay/claude-skills-plugin/backend-architecture-design
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.

Any agent
npx skills add LeekJay/claude-skills-plugin --skill backend-architecture-design
Clone the repo
git clone --depth 1 https://github.com/LeekJay/claude-skills-plugin

Made for: Claude Code.

Or install backend-architecture-design, the plugin that ships this one along with the rest of its 1 skill, 1 agent.

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 backend-architecture-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/leekjay/claude-skills-plugin/backend-architecture-design/github.svg)](https://agentmods.dev/skills/leekjay/claude-skills-plugin/backend-architecture-design)
Your own site
<a href="https://agentmods.dev/skills/leekjay/claude-skills-plugin/backend-architecture-design"><img src="https://agentmods.dev/badge/skills/leekjay/claude-skills-plugin/backend-architecture-design/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 backend-architecture-design

Your own site · 80×15
<a href="https://agentmods.dev/skills/leekjay/claude-skills-plugin/backend-architecture-design"><img src="https://agentmods.dev/badge/skills/leekjay/claude-skills-plugin/backend-architecture-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,956 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 $0.00080 $0.02956
Opus 5 $0.00040 $0.01478
Sonnet 5 $0.00016 $0.00591
Haiku 4.5 $0.00008 $0.00296

Measured 10d ago against content hash f892f2686a04, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

backend-architecture-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 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.

plugins/backend-architecture-design/skills/backend-architecture-design/SKILL.md · 418 lines

How it starts

The opening of the file, as written. The whole thing — 418 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Backend Architecture Design & Review

Comprehensive Python FastAPI backend project architecture review from six key dimensions: API design, data architecture, security, async performance, code organization, and testing & quality.

Decision Framework

Default behavior: For backend architecture review tasks, prefer Sub-Agent mode for thorough analysis.

🔴 Mandatory Sub-Agent Triggers (ANY ONE triggers delegation)

  1. Full architecture review: User requests comprehensive backend architecture analysis
  2. Multi-dimension analysis: Needs evaluation across 2+ dimensions (API, security, performance, etc.)
  3. Security assessment: Any security-related review or audit request
  4. Database optimization: N+1 detection, query optimization, schema review
  5. Redesign request: User mentions "redesign", "restructure", "overhaul", "major refactor"
  6. Performance audit: Async performance analysis, bottleneck detection
  7. Report generation: User wants a formal architecture review report
  8. Migration planning: Database migration, API versioning, framework upgrade
  9. Large codebase: Project has 20+ API endpoints or 30+ source files

🟢 Main Conversation Handling (ALL conditions must be met)

  1. Single dimension: Only checking one specific aspect (e.g., "is this endpoint RESTful?")
  2. Quick question: Simple questions like "is this pattern okay?" or "should I use Depends here?"
  3. Small scope: Looking at 1-3 specific files or endpoints
  4. No report needed: Just need quick feedback, not a formal report

Decision Flow

Check for ANY 🔴 mandatory trigger?
  ├─ YES → ✅ USE SUB-AGENT MODE immediately
  │         subagent_type="backend-architecture-design:backend-architecture-design"
  └─ NO → Check if ALL 🟢 simple conditions are met?
           ├─ YES → Handle in main conversation
           └─ NO → ✅ USE SUB-AGENT MODE (default behavior)

Quick Reference Examples

User Description Trigger Signal Decision
"Review the backend architecture" 🔴 Full review Sub-Agent
"Is this endpoint naming correct?" 🟢 Quick question, small scope Main conversation
"Check API design and security" 🔴 Multi-dimension Sub-Agent
"Review authentication implementation" 🔴 Security assessment Sub-Agent
"Find N+1 queries in the project" 🔴 Database optimization Sub-Agent
"Should I use async here?" 🟢 Quick question Main conversation
"Generate architecture report" 🔴 Report generation Sub-Agent
"Is this Pydantic model okay?" 🟢 Quick question, small scope Main conversation

Read the full file on GitHub · 418 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 418 lines · 80 tokens per session scan A f892f2686a04

Subscribe to this mod's changes

backend-architecture-design is a skill published in the GitHub repository LeekJay/claude-skills-plugin (4 stars, last pushed 9mo ago), licensed MIT. It adds 80 tokens to every session and 2,956 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.

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