Add library docs page

[devin-ai-integration]

Add library docs page

Summary

Adds a new documentation page for the Library Docs feature (beta) — Fern's ability to generate reference documentation for client libraries directly from source code. The page is placed in the API References > Generation section of the Docs product, alongside the existing REST, Webhook, WebSocket, OpenRPC, gRPC, and GraphQL reference pages.

The page covers:

• How library docs works (overview of the libraries config → fern docs md generate → library nav item workflow)
• Step-by-step configuration guide
• Supported languages (Python, C++ — both beta)
• Configuration reference for libraries (top-level) and library (navigation item)
• Multi-library example

Content was derived from the Fern CLI schema (docs.yml API definition), fern-platform LibraryDocsService, and CLI changelog entries (v3.42–v3.78).

Updates since last revision

• Fixed vale lint warnings: removed time-relative terms ("currently", "today") from the beta note.

Review & Testing Checklist for Human

• Content accuracy: The documented configuration schema and workflow were inferred from source code and changelogs — not from an official product spec. Verify correctness against the actual implementation, especially the libraries config shape, fern docs md generate command behavior, and library navigation item properties.
• Product alignment: Confirm the product team wants this beta feature publicly documented at this time, and that the framing/scope is appropriate.
• Placement: The page is in "API References > Generation" — verify this is the right location. Library docs generates from source code (not from OpenAPI/AsyncAPI), so it may belong in its own section or elsewhere.
• Preview rendering: Verify the page renders correctly at the preview URL — check <Steps>, <Note>, code block highlighting, and markdown tables.

Notes

• Link to Devin run
• Requested by: Fern Support

[devin-ai-integration]

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[fern-api]

Requested by: paarth
Slack thread: View conversation

[github-actions]

⚠️ [vale] _{reported by reviewdog 🐶}
[FernStyles.Current] Avoid time-relative terms like 'currently' that become outdated

[github-actions]

⚠️ [vale] _{reported by reviewdog 🐶}
[FernStyles.Current] Avoid time-relative terms like 'today' that become outdated

[github-actions]

🌿 Preview your docs: https://fern-preview-e3d803c6-51ca-492c-8963-2585006bbdd4.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/docs/api-references/library-docs

[github-actions]

This PR is stale because it has been open 25 days with no activity. Remove stale label or comment or this will be closed in 5 days.