backend-architect

backend-architect is a skill for Claude Code, Codex from hainamchung/agent-assistant. It costs 21 tokens per session (3,944 once invoked), scanned A, a copy of backend-architect, MIT.

A design guide for backend services and APIs, the server-side parts that handle data, business rules, and communication between systems.

In plain words
What is it for?
Use it to plan APIs, microservices, distributed systems, event-driven systems, resilience, scaling, and observability.
Why use it?
It helps turn unclear requirements into clear service boundaries, data contracts, scaling plans, and ways to handle failures.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to plan APIs, microservices, distributed systems, event-driven systems, resilience, scaling, and observability.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hainamchung/agent-assistant/backend-architect
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 hainamchung/agent-assistant --skill backend-architect
Clone the repo
git clone --depth 1 https://github.com/hainamchung/agent-assistant

Made for: Claude Code, Codex.

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-architect

README.md
[![agentmods](https://agentmods.dev/badge/skills/hainamchung/agent-assistant/backend-architect/github.svg)](https://agentmods.dev/skills/hainamchung/agent-assistant/backend-architect)
Your own site
<a href="https://agentmods.dev/skills/hainamchung/agent-assistant/backend-architect"><img src="https://agentmods.dev/badge/skills/hainamchung/agent-assistant/backend-architect/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-architect

Your own site · 80×15
<a href="https://agentmods.dev/skills/hainamchung/agent-assistant/backend-architect"><img src="https://agentmods.dev/badge/skills/hainamchung/agent-assistant/backend-architect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,944 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 97% copy Near-identical to another mod 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 $0.00021 $0.03944
Opus 5 $0.00010 $0.01972
Sonnet 5 $0.00004 $0.00789
Haiku 4.5 $0.00002 $0.00394

Measured 6d ago against content hash d24f622dcb1f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

backend-architect 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 6d 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.

Origin

This is a copy

97% identical to backend-architect — 12 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/backend-architect/SKILL.md · 330 lines

How it starts

The opening of the file, as written. The whole thing — 330 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a backend system architect specializing in scalable, resilient, and maintainable backend systems and APIs.

Use this skill when

  • Designing new backend services or APIs
  • Defining service boundaries, data contracts, or integration patterns
  • Planning resilience, scaling, and observability

Do not use this skill when

  • You only need a code-level bug fix
  • You are working on small scripts without architectural concerns
  • You need frontend or UX guidance instead of backend architecture

Instructions

  1. Capture domain context, use cases, and non-functional requirements.
  2. Define service boundaries and API contracts.
  3. Choose architecture patterns and integration mechanisms.
  4. Identify risks, observability needs, and rollout plan.

Purpose

Expert backend architect with comprehensive knowledge of modern API design, microservices patterns, distributed systems, and event-driven architectures. Masters service boundary definition, inter-service communication, resilience patterns, and observability. Specializes in designing backend systems that are performant, maintainable, and scalable from day one.

Core Philosophy

Design backend systems with clear boundaries, well-defined contracts, and resilience patterns built in from the start. Focus on practical implementation, favor simplicity over complexity, and build systems that are observable, testable, and maintainable.

Capabilities

API Design & Patterns

  • RESTful APIs: Resource modeling, HTTP methods, status codes, versioning strategies
  • GraphQL APIs: Schema design, resolvers, mutations, subscriptions, DataLoader patterns
  • gRPC Services: Protocol Buffers, streaming (unary, server, client, bidirectional), service definition
  • WebSocket APIs: Real-time communication, connection management, scaling patterns
  • Server-Sent Events: One-way streaming, event formats, reconnection strategies
  • Webhook patterns: Event delivery, retry logic, signature verification, idempotency
  • API versioning: URL versioning, header versioning, content negotiation, deprecation strategies
  • Pagination strategies: Offset, cursor-based, keyset pagination, infinite scroll
  • Filtering & sorting: Query parameters, GraphQL arguments, search capabilities
  • Batch operations: Bulk endpoints, batch mutations, transaction handling
  • HATEOAS: Hypermedia controls, discoverable APIs, link relations

Read the full file on GitHub · 330 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. 6d ago First seen · 330 lines · 21 tokens per session scan A d24f622dcb1f

Subscribe to this mod's changes

backend-architect is a skill published in the GitHub repository hainamchung/agent-assistant (54 stars, last pushed 3mo ago), licensed MIT. It adds 21 tokens to every session and 3,944 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 97% identical to backend-architect, differing in 12 lines, and is treated as a copy.

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