active-record-schema-designer

active-record-schema-designer is an agent for coding agents from slbug/claude-ruby-grape-rails. It costs 34 tokens per session (151 once invoked), scanned A, original, MIT.

A design and review specialist for database schemas in Ruby applications using Active Record, the database layer commonly used by Rails. It covers tables, relationships, migrations, indexes, constraints, locking, and query loading.

In plain words
What is it for?
Use it to design or review columns, foreign keys, unique and partial indexes, migration safety, transaction boundaries, locking strategies, and preload plans for Rails or Grape applications.
Why use it?
It helps prevent duplicate data, unsafe database changes, race conditions, and slow queries before they reach production. It also checks whether the schema supports the way the application will query it.

Agent

Part of the ruby-grape-rails plugin — 23 skills, 19 agents, 17 hooks 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 agents/slbug/claude-ruby-grape-rails/active-record-schema-designer
Clone the repo
git clone --depth 1 https://github.com/slbug/claude-ruby-grape-rails

Or install ruby-grape-rails, the plugin that ships this one along with the rest of its 23 skills, 19 agents, 17 hooks.

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 active-record-schema-designer

README.md
[![agentmods](https://agentmods.dev/badge/agents/slbug/claude-ruby-grape-rails/active-record-schema-designer.svg)](https://agentmods.dev/agents/slbug/claude-ruby-grape-rails/active-record-schema-designer)
Your own site
<a href="https://agentmods.dev/agents/slbug/claude-ruby-grape-rails/active-record-schema-designer"><img src="https://agentmods.dev/badge/agents/slbug/claude-ruby-grape-rails/active-record-schema-designer.svg" alt="Measured on agentmods" height="20"></a>
Per session 34 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 151 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 $0.00034 $0.00151
Opus 5 $0.00017 $0.00076
Sonnet 5 $0.00007 $0.00030
Haiku 4.5 $0.00003 $0.00015

Measured 4d ago against content hash fe3e5c136c56, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

active-record-schema-designer 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 4d 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/ruby-grape-rails/agents/active-record-schema-designer.md · 24 lines

What it actually says

Active Record Schema Designer

Focus on:

  • correct column types
  • foreign keys and indexes
  • uniqueness and partial-index strategy
  • transaction boundaries
  • locking for race-prone invariants
  • migration safety on existing tables
  • query shape and preload strategy implied by the design
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. 4d ago First seen · 24 lines · 34 tokens per session scan A fe3e5c136c56

Subscribe to this mod's changes

active-record-schema-designer is an agent published in the GitHub repository slbug/claude-ruby-grape-rails (7 stars, last pushed 5d ago), licensed MIT. It adds 34 tokens to every session and 151 once invoked, about $0.0002 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.

Related

Other agents, from other repositories