What is active-record-patterns?

A guide to using Active Record, Rails' database layer, for models, queries, relationships, transactions, locking, and migrations.

Use it when designing database models and associations, composing queries, processing large batches, protecting concurrent changes, or writing production-safe migrations.

It helps avoid duplicate database queries, unsafe updates during races, broken money handling, and migrations that are difficult to run safely.

active-record-patterns — Skill for Claude Code by slbug

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 slbug/claude-ruby-grape-rails --skill active-record-patterns

Clone the repo

git clone --depth 1 https://github.com/slbug/claude-ruby-grape-rails

Made for: Claude Code.

Or install ruby-grape-rails, the plugin that ships this one along with the rest of its 52 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/active-record-patterns/github.svg)](https://agentmods.dev/skills/slbug/claude-ruby-grape-rails/active-record-patterns)

Your own site

<a href="https://agentmods.dev/skills/slbug/claude-ruby-grape-rails/active-record-patterns"><img src="https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/active-record-patterns/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/slbug/claude-ruby-grape-rails/active-record-patterns"><img src="https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/active-record-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 390 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.

Model	Per session	Once invoked
Fable 5.1	$0.00050	$0.00390
Opus 5.5	$0.00020	$0.00156
Sonnet 5.5	$0.00010	$0.00078
Haiku 4.5	$0.00005	$0.00039

Measured 1mo ago against content hash 238de1ed6d0f, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

active-record-patterns 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 1mo 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/skills/active-record-patterns/SKILL.md · 40 lines

What it actually says

Active Record Patterns

Iron Laws

Use decimal or integer cents for money.
Prevent N+1 queries with intentional preload strategy.
Put invariants inside transactions and use locks when races matter.
Prefer after_commit for external side effects.
Keep schema constraints aligned with application validations.

Default Moves

use foreign keys and indexes deliberately
choose includes, preload, or eager_load intentionally
use find_each for large backfills and batch work
use optimistic or pessimistic locking where correctness depends on it
make migrations reversible and production-safe

References

Need	Reference
transactions, locking, partial-failure recovery	`${CLAUDE_SKILL_DIR}/references/transactions.md`
validation patterns, `update_columns` audit trails	`${CLAUDE_SKILL_DIR}/references/validations.md`
query composition, scopes, subqueries, batched inserts	`${CLAUDE_SKILL_DIR}/references/queries.md`
production-safe migration recipes	`${CLAUDE_SKILL_DIR}/references/migrations.md`
PostgreSQL full-text + trigram + hybrid search	`${CLAUDE_SKILL_DIR}/references/fulltext-search.md`

Sequel ORM (non-Active Record) work → /rb:sequel-patterns (Sequel ORM patterns)

Files

What ships with it

5 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.

1mo ago First seen · 40 lines · 50 tokens per session scan A 238de1ed6d0f

Subscribe to this mod's changes

active-record-patterns is a skill published in the GitHub repository slbug/claude-ruby-grape-rails (7 stars, last pushed 16d ago), licensed MIT. It adds 50 tokens to every session and 390 once invoked, about $0.0002 per session on Opus 5.5. 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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