[PR #21212] [MERGED] fix: preserve trailing slash in MCP server URLs #25971

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GiteaMirror · 2026-04-20T06:14:37-05:00

GiteaMirror commented

2026-04-20 06:14:37 -05:00

📋 Pull Request Information

Original PR: https://github.com/open-webui/open-webui/pull/21212
Author: @veeceey
Created: 2/6/2026
Status: ✅ Merged
Merged: 2/16/2026
Merged by: @tjbck

Base: dev ← Head: fix/issue-21179-mcp-trailing-slash

📝 Commits (1)

5a33b19 fix: preserve trailing slash in MCP server URLs

📊 Changes

1 file changed (+6 additions, -2 deletions)

View changed files

📝 src/lib/components/AddToolServerModal.svelte (+6 -2)

📄 Description

Pull Request Checklist

Target branch: Verify that the pull request targets the dev branch.
Description: Provide a concise description of the changes made in this pull request down below.
Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
Testing: Performed manual tests to verify the implemented fix works as intended AND does not break any other functionality.
Agentic AI Code: This Pull Request has gone through additional human review AND manual testing.
Code review: Performed a self-review of the code.
Title Prefix: Prefixed with fix: to categorize this pull request.

Changelog Entry

Description

Fixes MCP server URLs having their trailing slashes stripped on save, causing 301 redirects that drop Authorization headers (resulting in 400 Bad Request). The trailing-slash trim is now conditionally skipped when the connection type is mcp, while OpenAPI connections continue to behave as before.

Fixes #21179

Changed

Modified src/lib/components/AddToolServerModal.svelte:
- Wrapped the trailing-slash strip in a type !== 'mcp' guard so MCP server URLs are preserved exactly as entered
- OpenAPI tool server URLs continue to have trailing slashes stripped (existing behavior)

Fixed

Fixed MCP tool servers with trailing-slash URLs failing to connect due to 301 redirect dropping auth headers

Additional Information

Root Cause

In AddToolServerModal.svelte, the submitHandler unconditionally stripped trailing slashes:

url = url.replace(/\/$/, '');

This is correct for OpenAPI connections (which append paths like /openapi.json), but MCP (Streamable HTTP) URLs are used as-is for direct POST requests. Some MCP servers (e.g., Bitrix24) require a trailing slash. Without it, the server responds with a 301 redirect, and the HTTP client drops the Authorization header on redirect, causing a 400 Bad Request.

Fix

if (type !== 'mcp') {
    url = url.replace(/\/$/, '');
}

Screenshots or Videos

Test Results

Scenario	URL Entered	Saved URL (Before)	Saved URL (After)	Result
MCP with trailing slash	`https://api.example.com/mcp/`	`https://api.example.com/mcp` (broken)	`https://api.example.com/mcp/` (works)	Fixed
MCP without trailing slash	`https://api.example.com/mcp`	`https://api.example.com/mcp`	`https://api.example.com/mcp`	No change
OpenAPI with trailing slash	`https://api.example.com/v1/`	`https://api.example.com/v1`	`https://api.example.com/v1`	No change
OpenAPI without trailing slash	`https://api.example.com/v1`	`https://api.example.com/v1`	`https://api.example.com/v1`	No change

Contributor License Agreement

By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/open-webui/open-webui/pull/21212 **Author:** [@veeceey](https://github.com/veeceey) **Created:** 2/6/2026 **Status:** ✅ Merged **Merged:** 2/16/2026 **Merged by:** [@tjbck](https://github.com/tjbck) **Base:** `dev` ← **Head:** `fix/issue-21179-mcp-trailing-slash` --- ### 📝 Commits (1) - [`5a33b19`](https://github.com/open-webui/open-webui/commit/5a33b1901b3234923be634f7c568c46054a7b6e7) fix: preserve trailing slash in MCP server URLs ### 📊 Changes **1 file changed** (+6 additions, -2 deletions) <details> <summary>View changed files</summary> 📝 `src/lib/components/AddToolServerModal.svelte` (+6 -2) </details> ### 📄 Description # Pull Request Checklist - [x] **Target branch:** Verify that the pull request targets the `dev` branch. - [x] **Description:** Provide a concise description of the changes made in this pull request down below. - [x] **Changelog:** Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description. - [x] **Testing:** Performed manual tests to verify the implemented fix works as intended AND does not break any other functionality. - [x] **Agentic AI Code:** This Pull Request has gone through additional human review AND manual testing. - [x] **Code review:** Performed a self-review of the code. - [x] **Title Prefix:** Prefixed with `fix:` to categorize this pull request. # Changelog Entry ### Description Fixes MCP server URLs having their trailing slashes stripped on save, causing 301 redirects that drop `Authorization` headers (resulting in `400 Bad Request`). The trailing-slash trim is now conditionally skipped when the connection type is `mcp`, while OpenAPI connections continue to behave as before. Fixes #21179 ### Changed - Modified `src/lib/components/AddToolServerModal.svelte`: - Wrapped the trailing-slash strip in a `type !== 'mcp'` guard so MCP server URLs are preserved exactly as entered - OpenAPI tool server URLs continue to have trailing slashes stripped (existing behavior) ### Fixed - Fixed MCP tool servers with trailing-slash URLs failing to connect due to 301 redirect dropping auth headers --- ### Additional Information **Root Cause** In `AddToolServerModal.svelte`, the `submitHandler` unconditionally stripped trailing slashes: ```js url = url.replace(/\/$/, ''); ``` This is correct for OpenAPI connections (which append paths like `/openapi.json`), but MCP (Streamable HTTP) URLs are used as-is for direct POST requests. Some MCP servers (e.g., Bitrix24) require a trailing slash. Without it, the server responds with a 301 redirect, and the HTTP client drops the `Authorization` header on redirect, causing a `400 Bad Request`. **Fix** ```js if (type !== 'mcp') { url = url.replace(/\/$/, ''); } ``` ### Screenshots or Videos **Test Results** | Scenario | URL Entered | Saved URL (Before) | Saved URL (After) | Result | |----------|-------------|--------------------|--------------------|--------| | MCP with trailing slash | `https://api.example.com/mcp/` | `https://api.example.com/mcp` (broken) | `https://api.example.com/mcp/` (works) | Fixed | | MCP without trailing slash | `https://api.example.com/mcp` | `https://api.example.com/mcp` | `https://api.example.com/mcp` | No change | | OpenAPI with trailing slash | `https://api.example.com/v1/` | `https://api.example.com/v1` | `https://api.example.com/v1` | No change | | OpenAPI without trailing slash | `https://api.example.com/v1` | `https://api.example.com/v1` | `https://api.example.com/v1` | No change | ### Contributor License Agreement By submitting this pull request, I confirm that I have read and fully agree to the [Contributor License Agreement (CLA)](https://github.com/open-webui/open-webui/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT), and I am providing my contributions under its terms. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>

GiteaMirror added the pull-request label 2026-04-20 06:14:37 -05:00

GiteaMirror closed this issue

2026-04-20 06:14:38 -05:00

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Reference: github-starred/open-webui#25971