Ensure MCP server names are validated, improve detection of errors due to invalid MCP server names

Describe the bug

PS C:\Users\satem> copilot -p "hello world"
\× Model call failed: "400 400 Bad Request\n"

\× Model call failed: "400 400 Bad Request\n"

× Model call failed: "400 400 Bad Request\n"

× Model call failed: "400 400 Bad Request\n"

× Model call failed: "400 400 Bad Request\n"

× Model call failed: "400 400 Bad Request\n"

× Execution failed: Failed to get response from the AI model; retried 5 times (total retry wait 
   time: 90.0143845786254 seconds)

PS C:\Users\satem>

Affected version

No response

Steps to reproduce the behavior

No response

Expected behavior

No response

Additional context

No response

I had the same problem, but updating to the latest version fixed it.

npm install -g @github/copilot@latest

Try running

I'm sorry.
After communicating with copilot several times, the problem recurred,
so it seems the above alone is not enough.

same stuff

For me, mcp name with a space caused the problem. Fixed by removing the space.

@jazzbearz

@jazzbearz you are God sent. Yes MCP names with space caused the problem. I fixed it and it worked. see below:

 Welcome to GitHub Copilot CLI
 Version 0.0.331 · Commit eb0ae04

 Copilot can write, test and debug code right from your terminal. Describe a
 task to get started or enter ? for help. Copilot uses AI, check for mistakes.

 Windows support is experimental. If you encounter issues, consider running
 Copilot inside Windows Subsystem for Linux (WSL). Please report any issues
 using /feedback.

 ● Logged in as user: ...

 ● Configured MCP servers: Chrome DevTools

 ● Connected to GitHub MCP Server

 ╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
 │ > hello                                                                                                                                                                                                                                 │
 ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

 × Model call failed: "400 400 Bad Request\n"

 × Model call failed: "400 400 Bad Request\n"

 ● Operation cancelled by user

 ● MCP configuration saved successfully! Changes will take effect immediately.

 ● Configured MCP servers: ChromeDevTools

 ● Connected to GitHub MCP Server

 ╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
 │ > hello                                                                                                                                                                                                                                 │
 ╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

 ● Hello! 👋 I'm GitHub Copilot CLI,

@ekolawole

@ekolawole @yanskun @kukirokuk @jazzbearz : first, thank you all for opening helping one another understand the problem and arriving at a workaround! 🫶 🙇

Outside of improving the /mcp add and /mcp edit commands to validate server name doesn't contain spaces, I'm going to see if we can improve detecting errors raised being due to the server name in cases where people modify their MCP configuration.

@andyfeller

@andyfeller
Thank you for letting us know that there seems to be a problem with the naming of the MCP Server.

I'm not sure if this will help, but I thought I'd share.
My MCP Server name didn't appear to have spaces.

$ cat ~/.copilot/mcp-config.json

{
  "mcpServers": {
    "deepwiki": {
      "type": "sse",
      "url": "https://mcp.deepwiki.com/sse"
    },
    "context7": {
      "type": "http",
      "url": "https://mcp.context7.com/mcp"
    },
    "serena": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "--from",
        "git+http://github.com/oraios/serena",
        "serena-mcp-server",
        "--context",
        "ide-assistant",
        "--project",
        "${PWD}"
      ],
      "env": {}
    },
    "sentry": {
      "type": "http",
      "url": "https://mcp.sentry.dev/mcp"
    },
    "notion": {
      "type": "http",
      "url": "https://mcp.notion.com/mcp"
    },
    "chrome-devtools": {
      "type": "stdio",
      "command": "npx",
      "args": ["chrome-devtools-mcp@latest"]
    }
  }
}

Also,
after getting 400,
you can exit the session,
then use copilot --continue to open the same prompt and it will be successful.

@yanskun

I'm not sure if this will help, but I thought I'd share.
My MCP Server name didn't appear to have spaces.

That is verify interesting; thank you, @yanskun 🙇

I'd be grateful for any help examining your local logs for any additional insights into errors or what else might have arose to indicate why it was failing if name only contained a-zA-Z0-9_-. Also, any request IDs you'd share. 🤔

This has shipped in 0.0.337! http://github.com/github/copilot-cli/releases/tag/v0.0.337

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Ensure MCP server names are validated, improve detection of errors due to invalid MCP server names #110

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Ensure MCP server names are validated, improve detection of errors due to invalid MCP server names #110

Description

Describe the bug

Affected version

Steps to reproduce the behavior

Expected behavior

Additional context

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yanskun commented on Sep 29, 2025

yanskun commented on Sep 29, 2025

kukirokuk commented on Oct 1, 2025

jazzbearz commented on Oct 1, 2025

ekolawole commented on Oct 1, 2025

andyfeller commented on Oct 7, 2025

yanskun commented on Oct 8, 2025

andyfeller commented on Oct 8, 2025

RyanHecht commented on Oct 8, 2025

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