schema

schema is a skill for Claude Code from elct9620/ai-coding-skills. It costs 73 tokens per session (1,398 once invoked), scanned A, original, Apache-2.0.

A guide for designing database structures and API contracts—the agreed shapes of data sent between systems or layers. It covers tables, columns, indexes, request and response formats, and serialization between layers.

In plain words
What is it for?
Use it for migrations, REST or GraphQL endpoints, data-transfer objects, request and response shapes, serialization, or schema normalization and optimization.
Why use it?
It helps keep boundary data explicit, consistent, and constrained when database or API structures change.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the coding plugin — 9 skills, 4 commands shipped together

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/elct9620/ai-coding-skills/schema
Any agent
npx skills add elct9620/ai-coding-skills --skill schema
Clone the repo
git clone --depth 1 https://github.com/elct9620/ai-coding-skills

Made for: Claude Code.

Or install coding, the plugin that ships this one along with the rest of its 9 skills, 4 commands.

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 schema

README.md
[![agentmods](https://agentmods.dev/badge/skills/elct9620/ai-coding-skills/schema.svg)](https://agentmods.dev/skills/elct9620/ai-coding-skills/schema)
Your own site
<a href="https://agentmods.dev/skills/elct9620/ai-coding-skills/schema"><img src="https://agentmods.dev/badge/skills/elct9620/ai-coding-skills/schema.svg" alt="Measured on agentmods" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,398 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 $0.00073 $0.01398
Opus 5 $0.00036 $0.00699
Sonnet 5 $0.00015 $0.00280
Haiku 4.5 $0.00007 $0.00140

Measured 5d ago against content hash 72c9852aab24, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

schema 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 5d 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.

skills/schema/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

  • Designing the domain objects that the schema persists? → Use domain-modeling
  • Schema change requires code restructuring? → Use refactoring
  • Unsure which architectural layer the DTO belongs in? → Use architecture

Applicability Rubric

Condition Pass Fail
Database structure change Adding/modifying tables, columns, or indexes No persistence changes
API contract work Designing or changing request/response shapes No API boundary changes
Data boundary crossing Serialization/deserialization between layers Data stays within single layer
Schema restructuring Normalizing, denormalizing, or optimizing existing schemas No structural changes needed

Apply when: Any condition passes

Core Principles

Schema Design Principles

Principle Description Violation Sign
Single Source of Truth Each fact stored exactly once Same data duplicated across tables without clear denormalization rationale
Explicit Contracts Schemas defined clearly, with non-obvious values (status codes, control bytes, enum semantics) described inline at the boundary Implicit structures, untyped fields, or values that require service code to interpret
Boundary Alignment Schema matches system boundary responsibilities Schema leaks internal details or couples unrelated concerns
Minimal Exposure Expose only what consumers need Internal fields visible in API responses, over-fetching by default

Schema Types

Type Clean Architecture Layer Purpose Boundary with Domain Modeling
Database Schema Infrastructure Persist and query data efficiently Translates domain entities into storage format
API Contract Interface Adapters Define external communication shape Maps domain output to external representation
DTO Interface Adapters Transfer data between layers Decouples domain model from transport format

Read the full file on GitHub · 132 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. 5d ago First seen · 132 lines · 73 tokens per session scan A 72c9852aab24

Subscribe to this mod's changes

schema is a skill published in the GitHub repository elct9620/ai-coding-skills (5 stars, last pushed 10d ago), licensed Apache-2.0. It adds 73 tokens to every session and 1,398 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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