Active Storage Validations is a Ruby gem for adding validation rules to files attached through Rails Active Storage. Rails developers use it to check whether uploaded images, videos, audio files, PDFs, and other attachments meet requirements such as type, size, dimensions, duration, or quantity.
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.
git 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/rules/igorkasyanchuk/active_storage_validations/spec-validators)<a href="https://agentmods.dev/rules/igorkasyanchuk/active_storage_validations/spec-validators"><img src="https://agentmods.dev/badge/rules/igorkasyanchuk/active_storage_validations/spec-validators/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.
<a href="https://agentmods.dev/rules/igorkasyanchuk/active_storage_validations/spec-validators"><img src="https://agentmods.dev/badge/rules/igorkasyanchuk/active_storage_validations/spec-validators.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00000 | $0.00395 |
| Opus 5.5 | $0.00000 | $0.00158 |
| Sonnet 5.5 | $0.00000 | $0.00079 |
| Haiku 4.5 | $0.00000 | $0.00040 |
Grade A, and why
spec-validators 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.
What it actually says
Validator specs
- Follow shared conventions in
spec.mdc(namedsubject,describe/context,described_class). - Boot via
require "rails_helper"(or rely on.rspec); helpers are auto-included forspec/validators. - Prefer
RSpec.describe ActiveStorageValidations::SomeValidator. - Set
let(:validator_test_class)to the dummy namespace (e.g.Size::Validator) andlet(:params) { {} }. - Compose shared behavior with
it_behaves_like, not Concern modules:"ASVAttachable","ASVErrorable","checks validator validity""works fine with attachables","is performance optimized""works with all rails common validation options"- comparison:
"comparison less_than option",less_than_or_equal_to,greater_than,greater_than_or_equal_to,between,equal_to
- Use
ValidatorHelpersexpectations:is_expected_to_be_valid,is_expected_not_to_be_valid,is_expected_to_include_error_message,is_expected_to_have_error_options. Integration / stacked-validator examples must passvalidator:(e.g.validator: :size). The filter iserror.options[:validator_type] == (kwargs[:validator] || validator_sym)— keep the parentheses. - Dummy models live under
test/dummy/app/models/<validator>/. - Cross-validator stacking belongs in
spec/validators/integration/orspec/integration/, not in a single-validator file. - Use
describefor named units/topics (#check_validity!,:less_than) andcontextfor situations (when …,with …,without …).
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 Changed 829a602208e9
- 1mo ago First seen · 22 lines · 0 tokens per session scan A 2e11e6cf85ca
spec-validators is a cursor rule published in the GitHub repository igorkasyanchuk/active_storage_validations (1,193 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 395 tokens. 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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