Add docs for fern docs link check CLI command

 (#5514)

Co-authored-by: fern-api[bot] <115122769+fern-api[bot]@users.noreply.github.com>
Co-authored-by: Devin Logan <devinannlogan@gmail.com>

Author: fern-api[bot]

fern/products/cli-api-reference/pages/commands.mdx

@@ -29,6 +29,7 @@ hideOnThisPage: true
 | [`fern docs md check`](#fern-docs-md-check) | Validate MDX syntax in documentation files |
 | [`fern docs theme export`](#fern-docs-theme-export) | Export theme-eligible fields from `docs.yml` into a standalone directory |
 | [`fern docs theme upload`](#fern-docs-theme-upload) | Upload a theme to Fern's registry |
+| [`fern docs link check`](#fern-docs-link-check) | Check for broken links on a live documentation site |
 | [`fern docs theme list`](#fern-docs-theme-list) | List all themes for your organization |
 
 ## SDK generation commands  
@@ -281,8 +282,6 @@ hideOnThisPage: true
     Use `fern check` to validate your API definition and Fern configuration, including [`fern.config.json`](/learn/sdks/overview/project-structure#fernconfigjson), `generators.yml`, and `docs.yml`. It checks for broken links, invalid API examples, configuration errors, and more. When all checks pass, the command produces no output.
 
      Most `fern check` rules — including [`broken-links`](/learn/docs/configuration/site-level-settings#check-configuration) — validate against the navigation tree built from your **local** config and do not crawl your live deployed site or follow external URLs. The exception is the [`missing-redirects` rule](/learn/docs/seo/redirects#catching-missing-redirects), which compares your local navigation against the previously published state and therefore requires `fern login` or `FERN_TOKEN`.
-    
-    To check links on a published site, use the link checker in the [Fern Dashboard](https://dashboard.buildwithfern.com/) instead. When all checks pass, the command produces no output.
 
     <CodeBlock title="terminal">
     ```bash
@@ -300,6 +299,10 @@ hideOnThisPage: true
         missing-redirects: error
     ```
 
+    <Info>
+      To check links on a published site, use [`fern docs link check`](#fern-docs-link-check) or the link checker in the [Fern Dashboard](https://dashboard.buildwithfern.com/) instead.
+    </Info>
+
     ### api
 
     Use `--api <api>` to specify which API you'd like to check. 
@@ -466,6 +469,73 @@ hideOnThisPage: true
 
   </Accordion>
 
+  <Accordion title="fern docs link check">
+
+    Use `fern docs link check` to scan a live documentation site for broken links. The command crawls the published site, checks every link, and reports broken (404) and blocked (403) URLs along with their source pages.
+
+    <CodeBlock title="terminal">
+    ```bash
+    fern docs link check [--url <url>] [--output <format>]
+    ```
+    </CodeBlock>
+
+    <Info>
+      Unlike the [`broken-links` rule](#fern-check) in `fern check`, which validates only internal links in your local YAML navigation tree, `fern docs link check` checks all links — internal and external — on your live deployed site.
+    </Info>
+
+    By default, the command auto-detects your docs URL from the `instances` in `docs.yml`. When all links are valid, the command exits with a success message.
+
+    The command first scrapes every page on the site, then checks each link it finds. When broken links are found, the output includes a summary and a grouped list of broken URLs with status codes and source file paths.
+
+    ```plaintext
+    ◆ Checking links on your-org.docs.buildwithfern.com...
+
+      Scraping pages [████████████████████] 100% | 42/42
+      Checking links [████████████████████] 100% | 240/240
+
+    Finished in 2 minutes, 23 seconds
+
+    Summary
+        Pages scanned    42
+        Links checked    240
+        ✓ Working        228
+        ✗ Broken         8 (external)
+        ⚠ Blocked        4
+
+    ─────────────────────────────────────
+
+    External Broken Links (8)
+
+      ✗ https://example.com/removed-page → 404
+            fern/pages/quickstart.mdx
+            fern/pages/overview.mdx
+
+      ✗ https://example.com/old-endpoint → 404
+            fern/pages/integrations.mdx
+    ```
+
+    ### url
+
+    Use `--url` to specify which docs site to check. This is useful when you have multiple instances or want to check a preview deployment.
+
+    ```bash
+    fern docs link check --url https://your-org.docs.buildwithfern.com
+    ```
+
+    ### output
+
+    Use `--output` to control the output format. Supported values are `text` (default), `json`, and `csv`.
+
+    ```bash
+    # JSON output for programmatic use
+    fern docs link check --output json
+
+    # CSV output for spreadsheets or reporting
+    fern docs link check --output csv
+    ```
+
+  </Accordion>
+
   <Accordion title="fern docs md check">
 
     Use `fern docs md check` to validate MDX syntax across all documentation pages referenced in your navigation configuration, including `docs.yml`, versioned configuration files, and product-specific YAML files.

fern/products/docs/pages/changelog/2026-05-14.mdx

@@ -0,0 +1,16 @@
+---
+tags: ["configuration"]
+---
+
+## CLI link checker
+
+You can now check for broken links on your live documentation site directly from the Fern CLI with `fern docs link check`. The command scrapes every page on your published site, checks all internal and external links, and reports broken (404) and blocked (403) URLs along with the source pages where they appear.
+
+```bash
+fern docs link check --url https://buildwithfern.com/learn
+fern docs link check --url https://elevenlabs.io/docs
+```
+
+This complements the existing [`broken-links` rule](/learn/docs/configuration/site-level-settings#check-configuration) in `fern check`, which validates internal links against your local YAML navigation tree. Use `fern docs link check` after publishing to catch live 404s and broken external URLs that local validation can't detect.
+
+<Button intent="none" outlined rightIcon="arrow-right" href="/learn/cli-api-reference/cli-reference/commands#fern-docs-link-check">Read the docs</Button>

fern/products/docs/pages/component-library/writing-content/markdown-basics.mdx

@@ -74,7 +74,14 @@ In [versioned docs](/learn/docs/configuration/versions), the same path lands on
 
 ### Validating links
 
-The [`broken-links` rule](/learn/docs/configuration/site-level-settings#check-configuration) — run by [`fern check`](/learn/cli-api-reference/cli-reference/commands#fern-check), including during `fern docs dev` — validates each internal link against the navigation tree built from your **local** YAML. It does not crawl your deployed site or follow external URLs. To check links on a published site, use the [Fern Dashboard](https://dashboard.buildwithfern.com/).
+Fern provides two ways to catch broken links. The [`broken-links` rule](/learn/docs/configuration/site-level-settings#check-configuration) — run by [`fern check`](/learn/cli-api-reference/cli-reference/commands#fern-check), including during `fern docs dev` — validates each internal link against the navigation tree built from your **local** YAML. To check links on a published site, use [`fern docs link check`](/learn/cli-api-reference/cli-reference/commands#fern-docs-link-check) or the [Fern Dashboard](https://dashboard.buildwithfern.com/).
+
+| | `fern check` broken-links rule | `fern docs link check` |
+|---|---|---|
+| What it checks | Internal links in your **local** YAML navigation tree | All links on your **live deployed** site |
+| External links | Not checked | Checked |
+| Requires a published site | No | Yes |
+| When to use | In CI, before publishing | After publishing, to catch live 404s and broken external URLs |
 
 ### API link syntax