Workspace scoped MCP configuration fail under Windows

[bluemonkmn]

Problem

Workspace-scoped MCP configuration does not work under Windows. Attempting to change a global MCP configuration to a workspace configuration causes an error.

Steps to reproduce the issue

1. Define any valid Global MCP configuration (gets saved in %USERPROFILE%.aws\amazonq\mcp.json)
2. Go to VS Code's Amazon Q extension tab
3. Click the MCP server configuration icon
4. Select the MCP server
5. Click Edit Setup
6. Change the scope selection from "Global" to "This workspace"
7. Click Save
8. See error message l;ike: ENOENT: no such file or directory, mkdir 'C:\Users\bmarty\AppData\Local\Programs\Microsoft VS Code\file:\c%3A\landmark\ox3\src\hcm.amazonq\agents'

Expected behavior

The configuration should be moved from mcp.json to the root of the workspace in a directory called .amazonq. If a file is created in that location it should be picked up.

Actual Behavior

The extension is apparently failing to combine paths correctly or process the path representing the root of the workspace as a local path leading to an error like:

ENOENT: no such file or directory, mkdir 'C:\Users\bmarty\AppData\Local\Programs\Microsoft VS Code\file:\c%3A\landmark\ox3\src\hcm.amazonq\agents'

If a file is created in the correct location, it is not honored (no MCP configuration is seen).

System details

OS: Windows_NT x64 10.0.22631
Visual Studio Code extension host: 1.102.2
Amazon Q: 1.85.0
node: 22.15.1
electron: 35.6.0

[mjkubba]

Managed to replicate the issue, using vs codium:

ENOENT: no such file or directory, mkdir 'C:\Program Files\VSCodium\file:\i%3A\workspace\test.amazonq\agents'

looks like it's appending the file path to the host path, in the OP case it's VS code and my case it's VSCodium then the path to the local workspace.

Edit: system info:

Release: 24347
Commit: e4195c69747f84abd56a7d1d82fd9fa236511d26
Date: 2024-12-12T16:24:32.848Z
Electron: 32.2.7
ElectronBuildId: undefined
Chromium: 128.0.6613.186
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Windows_NT x64 10.0.26100```

[ashishrp-aws]

fix: aws/language-servers#2038

[DiscreteTom]

+1.

Workspace MCP servers not working for me on Windows, in both JetBrains IDEs (Amazon Q v3.89.251) and VSCode (Amazon Q v1.90.0). Both using language server v1.27.0.

[megarach0]

Hi, unfortunately as of 1.93.0 we're still seeing the issue. We're still convinced it has something to do with how Windows handles file paths as the error starts with ENOENT: no such file or directory after you try to configure an mcp configuration from global to a local workspace

[alexmadsen1]

i am getting issue to "no such file or directory, mkdir 'C:\Program Files\JetBrains\PyCharm 2025.2.1.1\file:\C:\Users\alexmad\PycharmProjects\AI_Eng_Dwg_Check_Brazil_WS.amazonq\agents'" ---
Toolkit: Amazon Q For JetBrains 3.93.252
OS: Windows 11.0
IDE: PyCharm 252

[alexmadsen1]

Root Cause Analysis: Windows MCP Workspace Configuration Bug
Problem Summary
Workspace-scoped MCP configuration fails on Windows with error:

'ENOENT: no such file or directory, mkdir 'C:\Program Files\JetBrains\PyCharm\file:\C:\Users...\workspace.amazonq\agents''

Root Cause Identified
Location: plugins/amazonq/shared/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonq/lsp/util/LspEditorUtil.kt

Function: toUri() (lines 44-56)

Issue: The URI construction incorrectly handles Windows paths, creating malformed URIs that get interpreted as literal file paths during directory creation.

Problematic Code

'private fun toUri(file: File): URI {
try {
// URI scheme specified by language server protocol
val uri = URI("file", "", file.absoluteFile.toURI().path, null) // ← BUG HERE
val fallback = file.toPath().toAbsolutePath().normalize().toUri()
return if (uri.isCompliant()) uri else fallback
} catch (e: URISyntaxException) {
LOG.warn { "${e.localizedMessage}: $e" }
return file.absoluteFile.toURI()
}
}'

What Happens
Input: C:\Users\alexmad\PycharmProjects\workspace

Line 44: file.absoluteFile.toURI().path returns /C:/Users/alexmad/PycharmProjects/workspace

Line 44: URI("file", "", "/C:/Users/...", null) creates file:///C:/Users/...

Problem: When this URI string is later used as a directory path, it becomes: C:\Program Files\JetBrains\PyCharm\file:\C:\Users...\workspace.amazonq\agents

Evidence
Cross-Platform Consistency
VS Code Error: mkdir 'C:\Users\bmarty\AppData\Local\Programs\Microsoft VS Code\file:\c%3A\landmark\ox3\src\hcm.amazonq\agents'

JetBrains Error: mkdir 'C:\Program Files\JetBrains\PyCharm\file:\C:\Users\alexmad\PycharmProjects\workspace.amazonq\agents'

Pattern: [IDE_INSTALL_PATH]\file:[WORKSPACE_PATH].amazonq\agents

Platform Specificity
Only affects Windows (both VS Code and JetBrains report Windows-only)

No Linux/macOS reports suggest Windows-specific path handling issue

Both VS Code (Node.js) and JetBrains (JVM) affected → shared language server component

Operation Specificity
Only occurs during workspace MCP configuration (not global)

Fails specifically on .amazonq\agents directory creation

Same mkdir operation across both IDEs

Cross-Platform Consistency
VS Code Error: mkdir 'C:\Users\bmarty\AppData\Local\Programs\Microsoft VS Code\file:\c%3A\landmark\ox3\src\hcm.amazonq\agents'

JetBrains Error: mkdir 'C:\Program Files\JetBrains\PyCharm\file:\C:\Users\alexmad\PycharmProjects\workspace.amazonq\agents'

Pattern: [IDE_INSTALL_PATH]\file:[WORKSPACE_PATH].amazonq\agents

Platform Specificity
Only affects Windows (both VS Code and JetBrains report Windows-only)

No Linux/macOS reports suggest Windows-specific path handling issue

Both VS Code (Node.js) and JetBrains (JVM) affected → shared language server component

Operation Specificity
Only occurs during workspace MCP configuration (not global)

Fails specifically on .amazonq\agents directory creation

Same mkdir operation across both IDEs

Proposed Fix
Replace the problematic URI construction with the working fallback:
private fun toUri(file: File): URI {
return file.toPath().toAbsolutePath().normalize().toUri()
}
Why this works:

Path.toUri() correctly handles Windows paths

Already implemented as fallback in current code

Eliminates the manual URI construction that causes the bug

Alternative Minimal Fix
If preserving the current logic is preferred:
private fun toUri(file: File): URI {
try {
val fallback = file.toPath().toAbsolutePath().normalize().toUri()
return fallback // Use fallback directly on Windows
} catch (e: URISyntaxException) {
LOG.warn { "${e.localizedMessage}: $e" }
return file.absoluteFile.toURI()
}
}

Impact
Fixes: Windows workspace MCP configuration

Risk: Low - uses existing fallback logic

Testing: Verify workspace MCP works on Windows while maintaining functionality on Linux/macOS

This fix resolves the issue for both VS Code and JetBrains IDEs since they share the same language server component.

[alexmadPDE]

@rli how do i get this fix pulled in, need it for a project. I am a hardware engineer by training but starting to dabble in SW. I work for Amazon so you can message me direct. [alexmadsen1] is my personal github and [alexmadPDE] is my work git hub account.

[alexmadPDE]

created pull request with fix
Fix Windows URI construction bug causing ENOENT errors in workspace-s… #6035 #7774

[megarach0]

@ashishrp-aws Any chance we can take a look at that PR?