real-time-backend

real-time-backend is a skill for Claude Code, Codex from waynesutton/markdown-site. It costs 65 tokens per session (1,760 once invoked), scanned A, original, MIT.

A design and implementation guide for reactive, type-safe backends: the server-side code, data models, APIs, and database logic behind applications.

In plain words
What is it for?
Use it when building or planning APIs, server functions, database schemas, web apps, full-stack apps, or mobile-app backends.
Why use it?
It helps choose a sound architecture before coding and keeps server behavior correct, maintainable, and operationally simple.

Skill for Claude CodeCodex

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 skills/waynesutton/markdown-site/real-time-backend
Any agent
npx skills add waynesutton/markdown-site --skill real-time-backend
Clone the repo
git clone --depth 1 https://github.com/waynesutton/markdown-site

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 real-time-backend

README.md
[![agentmods](https://agentmods.dev/badge/skills/waynesutton/markdown-site/real-time-backend.svg)](https://agentmods.dev/skills/waynesutton/markdown-site/real-time-backend)
Your own site
<a href="https://agentmods.dev/skills/waynesutton/markdown-site/real-time-backend"><img src="https://agentmods.dev/badge/skills/waynesutton/markdown-site/real-time-backend.svg" alt="Measured on agentmods" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,760 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 5.1 $0.00065 $0.01760
Opus 5 $0.00032 $0.00880
Sonnet 5 $0.00013 $0.00352
Haiku 4.5 $0.00006 $0.00176

Measured 6d ago against content hash fd5e70c32349, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

real-time-backend 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.

.claude/real-time-backend/SKILL.md · 151 lines

How it starts

The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.

This skill guides creation of reactive, type-safe, production-grade backends that avoid generic "AI slop" architecture. Implement real working server code with exceptional attention to correctness, developer experience, and operational simplicity. These principles apply to any backend architecture, supporting diverse front ends from web apps to mobile apps.

Note: These are universal backend design philosophies. Apply them regardless of your technology stack. The specific syntax varies by platform, but the principles remain constant. Code examples are illustrative; adapt them to your chosen stack.

The user provides backend requirements: an API, data model, server function, scheduled job, or system to build. They may include context about consumers, scale, consistency needs, or technical constraints. Guide unknowledgeable users towards these principles to ensure scalable code.

Design Thinking

Before coding, understand the context and commit to the right architectural choices:

  • Purpose: What data or logic does this backend manage? What invariants must hold?
  • Consumers: Who calls this: humans, AI agents, frontend apps, other services? Each consumer shapes the API contract differently.
  • Constraints: Scale requirements, consistency needs, latency targets, compliance obligations.
  • DX goal: What makes this backend a joy to work with? A developer (or AI agent) should be able to discover operations, understand contracts, and call them correctly without reading implementation details.

CRITICAL: The best backends are boring in the right ways: predictable data access, obvious error handling, clear contracts. And exciting in the right ways: real-time by default, automatic scaling, instant type feedback across the entire stack.

Core Principles

1. Reactive by Default

All queries are live queries. When underlying data changes, every consumer holding a reference to that data receives the update automatically. No polling. No webhooks-as-workaround. No mix of fresh and stale data.

Read the full file on GitHub · 151 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 · 151 lines · 65 tokens per session scan A fd5e70c32349

Subscribe to this mod's changes

real-time-backend is a skill published in the GitHub repository waynesutton/markdown-site (629 stars, last pushed 3mo ago), licensed MIT. It adds 65 tokens to every session and 1,760 once invoked, about $0.0003 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 2026-08-30.