Azure DevOps MCP Server Connected but CLI Commands Fail with "Dangerous Request.Path" Error

[fdambrosio]

Describe the bug

Description:

The ADO MCP server appears connected when using mcp show, and works correctly in Visual Studio Code, but fails when invoked via the Copilot CLI with a consistent error about "dangerous Request.Path values."

Steps to Reproduce:

1. Ensure ADO MCP server is configured and running (mcp show confirms connection)
2. Open Copilot CLI in the repo
3. Invoke any ADO MCP command that includes email addresses (e.g., WIQL query filtering by AssignedTo)
4. Observe the error response

Expected Behavior:

MCP commands that work in VS Code should also work in Copilot CLI without modification.

Actual Behavior:

Commands fail with:

Error executing WIQL query: {"$id":"1","innerException":null,"message":"A potentially dangerous Request.Path value was detected from the client (:).","typeName":"System.Web.HttpException, System.Web"...}

Error Occurs With:

• azure-devops-mcp-wit_query_by_wiql when filtering by [System.AssignedTo] (email contains :)
• azure-devops-mcp-wit_my_work_items (generic path issue)
• Any query/command that includes colons in parameters

Environment:

• Copilot CLI version:
  1.0.49
• Model: claude-haiku-4.5
• ADO MCP server: connected (verified via mcp show)
• OS: macOS
• VS Code: works fine with same MCP configuration

Hypothesis:

The CLI may be handling URL encoding/path escaping differently than VS Code, or the MCP server proxy in CLI has stricter security validation that prevents colons in certain contexts.

Requested:

• Debug/fix MCP server communication in CLI to match VS Code behavior
• Or document if email filtering requires URL encoding in CLI (e.g., %3A for :)

I'm using a mcp server allowed by organization:

"azure-devops-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@azure-devops/mcp@latest",
"${input:ado_org}"
],
...
"env": {
"ADO_MCP_AUTH_TOKEN": "{env:ADO_MCP_AUTH_TOKEN}"
},

Affected version

No response

Steps to reproduce the behavior

No response

Expected behavior

No response

Additional context

No response