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 skills add sandeepmvl/rails-skills --skill 17-rails-upgrade-6-to-7git clone --depth 1 https://github.com/sandeepmvl/rails-skillsWrote 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/skills/sandeepmvl/rails-skills/17-rails-upgrade-6-to-7)<a href="https://agentmods.dev/skills/sandeepmvl/rails-skills/17-rails-upgrade-6-to-7"><img src="https://agentmods.dev/badge/skills/sandeepmvl/rails-skills/17-rails-upgrade-6-to-7/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/skills/sandeepmvl/rails-skills/17-rails-upgrade-6-to-7"><img src="https://agentmods.dev/badge/skills/sandeepmvl/rails-skills/17-rails-upgrade-6-to-7.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 | $0.00129 | $0.01083 |
| Opus 5 | $0.00064 | $0.00541 |
| Sonnet 5 | $0.00026 | $0.00217 |
| Haiku 4.5 | $0.00013 | $0.00108 |
Grade A, and why
rails-upgrade-6-to-7 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 12d 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 — 105 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rails 6 → 7 Upgrade
Bigger hop than 7→8. Webpacker is gone. Zeitwerk autoloader is mandatory. Hotwire arrives. Treat it as a multi-week project for a non-trivial app.
The opinion
Dual-boot with
next_rails. Hop 6.0 → 6.1 → 7.0 → 7.1. Migrate off Webpacker as a separate project before or after — never inline with the version bump. Choose importmap-rails (default) or jsbundling-rails based on app size. Adopt Hotwire (Turbo+Stimulus) gradually if you have a heavy jQuery legacy.
The hop sequence
6.0 → 6.1 → 7.0 → 7.1
Core patterns
Pattern 1: 6.0 → 6.1
Key changes:
- Multi-DB support (
connects_to). - Stricter
enumsemantics. where.missing(:assoc)shortcut.delegated_typeshipped.
Hop, fix deprecations, ship.
Pattern 2: 6.1 → 7.0 — the big one
Required:
- Ruby 2.7+.
- Zeitwerk autoloader (was already in 6.0 as default — but 7.0 removes Classic).
Breaking-ish:
- Webpacker deprecated; replaced by importmap-rails or jsbundling-rails (esbuild / rollup / webpack still available).
- spring-watcher-listen removed.
- ActiveRecord Encryption ships (
encrypts :col).
Webpacker decision matrix:
| App | Pick |
|---|---|
| Server-rendered Rails + sprinkle of JS | importmap-rails (no Node build) |
| React/Vue SPA mixed in | jsbundling-rails with esbuild |
| Heavy CSS preprocessing | cssbundling-rails |
| Legacy Webpacker app, can't migrate yet | shakapacker (community fork) |
# Migrating from Webpacker (illustrative — full migration is its own skill)
# 1. Remove Webpacker, add importmap-rails
gem "importmap-rails"
# 2. bin/rails importmap:install
# 3. Move app/javascript/packs/* → app/javascript/*
# 4. Update layouts: <%= javascript_importmap_tags %>
# 5. Remove webpacker files, bin/webpack, etc.
Pattern 3: 7.0 → 7.1
Key changes:
Rails.error.reportarrives.async_count,load_async.- Trilogy gem for MySQL.
composed_ofdeprecated; use Attributes API.
Mild hop; mostly deprecation cleanup.
What ships with it
1 file 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.
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.
- 12d ago First seen · 105 lines · 129 tokens per session scan A ec22cee7236a
rails-upgrade-6-to-7 is a skill published in the GitHub repository sandeepmvl/rails-skills (21 stars, last pushed 3mo ago), licensed MIT. It adds 129 tokens to every session and 1,083 once invoked, about $0.0006 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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