[BUG] Azure MCP server fails in Antigravity with invalid character 'X' and connection closed during tools/call
Nobody has claimed this yet.
- Dominant language
- C#
- Stars
- 3.7k
- Forks
- 624
- Avg merge
- 2d 20h
- Merged PRs (30d)
- 220
Description
### Describe the bug
When configuring and running the Azure MCP server (both Node.js and Python variants), the MCP client fails to communicate with the server.
Although the server starts without engine/version errors, any tool invocation results in a connection failure with a JSON parsing error.
This appears to indicate that the MCP server is either:
emitting non-JSON output on stdout, or
closing the connection prematurely during MCP protocol communication
### Expected behavior
MCP server should successfully initialize via stdio
MCP client should be able to call tools without connection termination
Responses should be valid JSON-RPC messages as per MCP protocol
### Actual behavior
On tool invocation, the following error occurs:
```
Failure in MCP tool execution: connection closed: calling "tools/call": client is closing: invalid character 'X' looking for beginning of value
```
This happens consistently across both Node and Python implementations.
### Reproduction Steps
1. Configure MCP server (Node version):
```json
{
"mcpServers": {
"azure-mcp": {
"command": "/home/bharat/.nvm/versions/node/v22.21.1/bin/node",
"args": [
"/home/bharat/.nvm/versions/node/v22.21.1/bin/azmcp",
"server",
"start"
]
}
}
}
```
2. Alternatively, configure using Python (`uvx`):
```json
{
"mcpServers": {
"Azure MCP Server": {
"command": "uvx",
"args": [
"--from",
"msmcp-azure",
"azmcp",
"server",
"start"
]
}
}
}
```
3. Start Antigravity and ask question regarding azure enviorment like, what are all the function apps in my subscription.
4. Observe failure
### Environment
* MCP Client: Antigravity
* OS: Ubuntu (Latitude 5480)
* Node.js: v22.21.1
* npm: 10.9.4
* Python: (via `uvx`, version can be added if needed)
* Azure MCP package:
* Node: `@azure/mcp@latest`
* Python: `msmcp-azure`
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the failure with the Node @azure/mcp entry point and the Python msmcp-azure command shown in the issue, using Antigravity over stdio. Inspect the server output during initialization and tools/call for the reported invalid character and connection closure. Done means both variants initialize and return valid JSON-RPC responses for tool calls.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- azure, node.js, python
- Domain
- api, cloud
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 50/100