feat: add anchor validation to internal link checker

[RiskeyL]

Summary

Extend tools/check-links.py to validate the #anchor portion of internal links, not just the file portion. Previously the checker stripped anchors before resolving, so a link like /foo/bar#stale would pass as long as /foo/bar existed.

The checker now extracts anchors from:

• Markdown headings (with GFM duplicate-suffixing for repeats)
• Custom {#id} and <a id="..."> syntax
• Mintlify <Tab title="..."> and <Accordion title="...">, which generate per-tab anchors from the title attribute

Same-page #anchor links are validated against the source file. API reference paths (/api-reference/...) are skipped because their anchors come from OpenAPI specs rather than MDX content; supporting those would require resolving and parsing the spec referenced in docs.json.

Anchors fixed as a side effect

The new check surfaced 29 broken anchors across en/zh/ja, fixed in the second commit. They fall into three groups:

• Stale anchor slugs after heading renames or typos in en sources (e.g., #variable → #variables, URL-encoded colon in a Weaviate migration anchor).
• English anchors carried into zh/ja translations where the headings had been translated (e.g., #model-provider → #モデルプロバイダー / #模型提供商).
• Section-numbered references in datasource-plugin.mdx pointing to a "Hello World Guide" structure that no longer matches the current tool-plugin.mdx. Both link text and anchors updated.

[mintlify]

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Project	Status	Preview	Updated (UTC)
dify-core-product	🟢 Ready	View Preview	Apr 16, 2026, 12:51 PM

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[Copilot]

Pull request overview

Extend the docs link-checking tool to validate internal link fragments (#anchors) by extracting valid anchors from MDX/Markdown content, and fix newly-detected broken anchors across EN/JA/ZH docs.

Changes:

• Add per-file anchor extraction + validation to tools/check-links.py (headings, custom IDs, <a id="">, and Mintlify Tab/Accordion titles).
• Skip anchor validation for /api-reference/... links where anchors are not derived from page MDX.
• Update multiple documentation pages to use the correct (translated/updated) anchor slugs.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tools/check-links.py	Adds anchor extraction, caching, and validation for internal links with fragments.
en/use-dify/knowledge/test-retrieval.mdx	Fixes internal anchor to match updated heading slug in the indexing/retrieval settings page.
en/self-host/troubleshooting/weaviate-v4-migration.mdx	Fixes a percent-encoded anchor to the canonical slug form.
en/develop-plugin/features-and-specs/plugin-types/tool.mdx	Updates card links to correct anchors (variables, custom-output-variables).
en/develop-plugin/dev-guides-and-walkthroughs/datasource-plugin.mdx	Updates links to tool-plugin sections with current heading slugs.
ja/use-dify/nodes/user-input.mdx	Updates same-page anchor to match Japanese heading slug.
ja/use-dify/knowledge/test-retrieval.mdx	Fixes anchor/link text to match current Japanese section heading.
ja/self-host/troubleshooting/weaviate-v4-migration.mdx	Updates troubleshooting anchor to Japanese heading slug.
ja/develop-plugin/features-and-specs/plugin-types/tool.mdx	Updates card links to match Japanese section anchors.
ja/develop-plugin/features-and-specs/plugin-types/model-schema.mdx	Updates card links to match Japanese section anchors.
ja/develop-plugin/dev-guides-and-walkthroughs/datasource-plugin.mdx	Updates links to tool-plugin sections with current Japanese heading slugs.
zh/use-dify/nodes/user-input.mdx	Updates same-page anchor to match Chinese heading slug.
zh/self-host/troubleshooting/weaviate-v4-migration.mdx	Updates troubleshooting anchor to Chinese heading slug.
zh/develop-plugin/features-and-specs/plugin-types/tool.mdx	Updates card links to match Chinese section anchors.
zh/develop-plugin/features-and-specs/plugin-types/model-schema.mdx	Updates card links to match Chinese section anchors.
zh/develop-plugin/dev-guides-and-walkthroughs/datasource-plugin.mdx	Updates links to tool-plugin sections with current Chinese heading slugs.

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