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.
npx agentmods add instructions/igorkasyanchuk/active_storage_validations/agents-mdgit clone --depth 1 https://github.com/igorkasyanchuk/active_storage_validationsWrote 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.
[](https://agentmods.dev/instructions/igorkasyanchuk/active_storage_validations/agents-md)<a href="https://agentmods.dev/instructions/igorkasyanchuk/active_storage_validations/agents-md"><img src="https://agentmods.dev/badge/instructions/igorkasyanchuk/active_storage_validations/agents-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.03583 | $0.03583 |
| Opus 5 | $0.01792 | $0.01792 |
| Sonnet 5 | $0.00717 | $0.00717 |
| Haiku 4.5 | $0.00358 | $0.00358 |
Grade A, and why
active_storage_validations AGENTS.md 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.
How it starts
The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Active Storage Validations — Guide for AI Coding Agents
This is the codebase of the active_storage_validations gem: Active Model validators for Rails Active Storage attachments (presence, content type, size, dimensions, duration, aspect ratio, PDF pages, etc.).
It is a gem, not a Rails application. Specs boot a Combustion dummy app under test/dummy/.
Architecture Overview
lib/active_storage_validations.rb # Entry point + infer_file_field_accept / command_timeout config
lib/active_storage_validations/
*_validator.rb # Validators (ActiveModel::EachValidator)
base_comparison_validator.rb # Shared comparison options (<, <=, >, >=, between, equal_to)
shared/asv_*.rb # Shared concerns used by validators
analyzer/ # Media metadata extractors (image/video/audio/pdf)
analyzer/content_type_analyzer/ # Spoofing sniffers: File + Magika backends
extensors/ # Blob metadata + Marcel helpers
matchers/ # Opt-in RSpec/Minitest matchers (consumer-facing)
form_builder.rb # Infers HTML accept from content_type validators
railtie.rb / engine.rb # Rails integration + locale loading
config/locales/*.yml # I18n error messages (all locales must stay in sync)
spec/ # RSpec suite (validators, matchers, analyzers, form_builder, integration)
test/dummy/ # Combustion Rails app + per-validator models
gemfiles/ # Per-Rails-version Bundler Gemfiles (not Appraisal)
benchmark/ # Optional ips / require suite (not shipped in the gem)
docs/upgrade_to_*.md # Upgrade guides
Key integration points (railtie.rb):
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.
- 4d ago First seen · 247 lines · 3,583 tokens per session scan A b6d6866981b2
active_storage_validations AGENTS.md is an instructions file published in the GitHub repository igorkasyanchuk/active_storage_validations (1,191 stars, last pushed 12d ago), licensed MIT. It adds 3,583 tokens to every session, about $0.0179 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.
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