✨ feat: Add server-side support for APP_TITLE and APP_DESCRIPTION metadata

[ucodia]

Summary

• Adds a new APP_DESCRIPTION environment variable that allows operators to customize the HTML <meta name="description"> tag content at runtime, following the same pattern as the existing APP_TITLE env var.
• Both APP_TITLE and APP_DESCRIPTION are now injected server-side into the HTML at startup, so crawlers and social-sharing previews see the correct values without JavaScript.
• The PWA manifest.webmanifest is dynamically served with name, short_name, and description reflecting the configured values.
• Shared default constants (defaultAppTitle, defaultAppDescription) ensure consistent fallback values across the codebase.
• Client-side hooks are preserved for SPA navigation and dev mode.

Change Type

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Testing

Test Configuration:

1. Set APP_TITLE=My App and APP_DESCRIPTION=My custom description in .env
2. Start the backend
3. SEO/server-side: curl http://localhost:3080/ — confirm <title>My App</title> and <meta name="description" content="My custom description" appear in the raw HTML (no JS required)
4. PWA manifest: curl http://localhost:3080/manifest.webmanifest — confirm "name": "My App", "short_name": "My App", and "description": "My custom description"
5. Config API: visit http://localhost:3080/api/config — confirm "appTitle": "My App" and "appDescription": "My custom description" are present
6. Client-side: Load the app in a browser, inspect the <title> and <meta name="description"> tags, confirm they match the configured values
7. Defaults: Remove both env vars, restart — confirm the title defaults to "LibreChat" and the description defaults to "LibreChat - An open source chat application with support for multiple AI models"
8. Unit tests: cd packages/api && npx jest appMetadata — 12 tests pass

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have made pertinent documentation changes
• My changes do not introduce new warnings
• Local unit tests pass with my changes
• A pull request for updating the documentation has been submitted: docs: add APP_DESCRIPTION option and clarify APP_TITLE description. LibreChat-AI/librechat.ai#543

[danny-avila]

Here's an automated review I ran:

What's Good

The approach is straightforward, follows the existing APP_TITLE pattern, and touches all the right layers: backend payload, shared type definition, frontend hook, and .env.example.

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Issues to Fix Before Merge

1. No real test coverage
The only test file change adds a cleanup line to an afterEach block inside a permanently-skipped describe block. Zero tests actually run. Neither the backend payload behavior nor the frontend DOM mutation is tested.

2. The SEO pitch doesn't hold up
Setting <meta name="description"> via JavaScript after a network request means crawlers (Google, Bing, social link previewers) will read the static index.html default, not the operator-configured value. If this is meant for branding/SEO, the implementation won't deliver. This needs to be documented clearly so operators aren't misled.

3. Inconsistent backend pattern
process.env.APP_DESCRIPTION || undefined is a confusing way to express "omit this key when unset." The rest of the file uses an explicit if block for optional env vars (see CUSTOM_FOOTER). Should match that pattern.

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Minor/Polish

• .env.example entry shows # APP_DESCRIPTION= with no example value or hint at what the default is
• The ?? '' coercion in the useEffect is redundant given the !appDescription guard immediately after
• The JSDoc comment narrates what the code does, which the project style guide explicitly discourages
• The useEffect depends on the entire startupConfig object when it only reads one field from it

[ucodia]

Thanks for the feedback @danny-avila

I did not indeed realize that a JS runtime update the DOM would defeat SEO in crawling/no JS scenarios. This actually reveals a more systematic issue with how LibreChat update the <title> tag as well. Doing a SEO check on my published stack revealed that meta title was still LibreChat.

This does need rework so I will think of a different strategy which may benefit all SEO and metadata related elements, including the app manifest.

[ucodia]

@danny-avila updated accordingly so that it works for SEO as you highlighted and added relevant tests. In fact this was already not happening with the APP_TITLE value which was injected at runtime. Since the app title and description also exists in the web manifest I went ahead and also updated them. Admittedly this is a wider scope than my original PR intended!