Rails official documentation lookup

Trained knowledge about Rails APIs can be outdated, mixed across versions, or simply wrong on specifics (option names, defaults, deprecations, callback ordering, etc.). Before answering a Rails-specific question or relying on a Rails API's exact behavior, check the official docs rather than guessing — pinned to the version this project actually runs, not whatever version training data assumed.

Determine the version first

Don't assume the Rails version from memory or from prose in CLAUDE.md — that can go stale the moment someone bumps the gem without updating the docs. Check the source of truth instead:

grep -m1 '^    rails (' Gemfile.lock

That gives you the exact installed version (e.g. rails (8.0.2.1)). Use its <major>.<minor> for the pinned doc URLs below.

Sources

• Guides (concepts, how-tos, conventions): https://guides.rubyonrails.org
  • Version-pinned: https://guides.rubyonrails.org/v<major>.<minor>/<guide-name>.html
• API reference (exact method signatures, options, source): https://api.rubyonrails.org
  • Version-pinned: https://api.rubyonrails.org/v<major>.<minor>/

If a pinned URL 404s (e.g. docs for a brand-new version aren't published at that path yet), fall back to the unpinned root and flag to the user that you're reading possibly-newer docs than the installed version.

When to look things up

Use WebFetch against the sources above when:

• The question is about a specific Rails API's options, defaults, or behavior (e.g. "does has_many support :strict_loading?", "what does config.active_record.encryption need?").
• You're unsure whether something changed between Rails versions (deprecated, renamed, new behavior in the installed version).
• You're about to write code that depends on exact method signatures, callback ordering, or routing/DSL syntax you're not fully certain of.
• The user asks a "how do I do X in Rails" question that isn't already answered by this project's own conventions in CLAUDE.md.

Skip the lookup for things you can verify faster by reading this codebase directly (e.g. "how does this app handle streaming?" — that's answered by app/services/ai_backend/, not the guides), or for very basic Ruby/Rails knowledge you're confident hasn't changed across versions.

How to look things up

1. Determine the installed Rails version from Gemfile.lock (see above).
2. Identify the right guide or API page (e.g. Active Record Associations, Action Mailer Basics).
3. Fetch it with WebFetch, using the version-pinned URL.
4. If the guide doesn't have the exact method signature, cross-check api.rubyonrails.org for the precise method/class documentation.
5. Prefer the official source over Stack Overflow, blog posts, or other secondary sources when they conflict.

Applying this project's conventions

Official Rails docs describe what's possible; they don't override this project's own patterns. After confirming Rails behavior, still follow CLAUDE.md's conventions — e.g. provider logic goes in app/services/ai_backend/, soft deletion via deleted_at + not_deleted scopes, feature flags via Feature.<name>?/Setting.<name>, and don't hard-code model lists (models.yml instead).