🧳 fix: Carry Custom Endpoint Names Through Chat URLs

[abhishekbiswas772]

Summary

Fixes #15270.

createPayload interpolated the endpoint name straight into the chat URL:

let server = `${EndpointURLs[s.EModelEndpoint.agents]}/${endpoint}`;

Custom endpoint names are user-defined, so a name like Company/API produces /api/agents/chat/Company/API. The slash reads as a path separator, the request stops matching the router's /:endpoint in api/server/routes/agents/chat.js, and it falls through to the catch-all handler in packages/api/src/middleware/notFound.ts — which is where the reported Endpoint not found actually comes from. It is the generic API 404, not an endpoint-resolution error, which is why the message gives no hint about the real cause.

Encoding the name keeps it a single path segment. Express matches the encoded segment and decodes req.params.endpoint back to the original value, and the endpoint the server acts on is read from the request body regardless (req.params.endpoint is never read anywhere in the codebase — the segment exists only for routing), so nothing downstream has to change.

This also aligns the call site with the encodeURIComponent convention already used throughout api-endpoints.ts.

I went with encoding rather than rejecting slashes at config-validation time, since the issue offers both and encoding keeps working configurations working. Happy to switch to validation instead if maintainers prefer that direction.

Change Type

• Bug fix (non-breaking change which fixes an issue)

Testing

Confirmed the routing behaviour empirically against this repo's Express version before writing the fix — a raw slash reproduces the exact reported 404, and the percent-encoded form matches /:endpoint and decodes back to Company/API.

Added packages/data-provider/specs/createPayload.spec.ts:

• builds the chat URL from a plain custom endpoint name
• percent-encodes a slash so the name stays a single path segment
• round-trips the encoded name back to the configured value
• encodes other characters unsafe in a path segment (space, ?, =, #)
• leaves the endpoint name itself untouched in the payload body
• does not touch the assistants URL, which carries no endpoint segment

The slash and unsafe-character cases fail without the fix; the rest pass either way, confirming existing URLs are unchanged.

cd packages/data-provider && npx jest
# 36 suites, 1701 tests passed

Test Configuration:

Node.js v24.16.0, Windows. Reproduces with any custom endpoint whose name contains /.

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• My changes do not introduce new warnings
• I have written tests demonstrating that my changes are effective
• Local unit tests pass with my changes

[github-actions]

👋 Thanks for the contribution! LibreChat merges all changes into dev first — main only moves at release time — so this pull request's base branch was switched from main to dev automatically.

Nothing is needed from you; your commits, reviews and discussion are unchanged. If the diff now shows files you did not touch, rebase onto dev:

git remote add upstream https://github.com/danny-avila/LibreChat.git
git fetch upstream dev
git rebase upstream/dev
git push --force-with-lease

Maintainers: apply the target: main label and restore the base branch if this one genuinely belongs on main.

[danny-avila]

@codex review

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-01T17:33:47.673371Z	0ea7400	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Nice work!

Reviewed commit: 0ea740002f

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