Cannot get MCP init on Google's Antigravity

[rolandorojas]

Laravel Package Version

1.8.1

Laravel Version

12.39.0

PHP Version

8.4.11

System Info

Windows 11 (x64) with Laragon

Description

I've been trying to set up Boost in Google's Antigravity, but keep getting a Error: calling "initialize": EOF or Error: calling "initialize": invalid trailing data at the end of stream error.

Here is my mcp_config.json using the same settings that work with Codex, Kilo, Junie, and (ironically) Gemini CLI.

mcp_config.json

{
    "mcpServers": {
        "laravel-boost": {
            "command": "C:\\laragon\\bin\\php\\php-8.4\\php.exe",
            "args": [
                "C:\\Projects\\MyProjectName\\artisan",
                "boost:mcp"
            ]
        }
    }
}

Antigravity version

Antigravity Version: 1.11.3
VSCode OSS Version: 1.104.0 (user setup)
Commit: 379750caac7172d89d256835378d03e766682227
Date: 2025-11-19T01:34:49.332Z
Electron: 37.3.1
Chromium: 138.0.7204.235
Node.js: 22.18.0
V8: 13.8.258.31-electron.0
OS: Windows_NT x64 10.0.26200
Language Server CL: 834030306

Steps To Reproduce

1. Open Antigravity
2. Switch to editor mode
3. Click the "Additional Options" (...) icon on the Agent panel and select "MCP Servers"
4. Add the MCP server config
5. Click "Refresh"

[pushpak1300]

Working in my testing in mac with above config. 😕

[backstageel]

I have the same error as @rolandorojas using Archlinux and Laravel Sail.
My MCP settings are:

{
    "mcpServers": {
        "laravel-boost": {
            "command": "./vendor/bin/sail",
            "args": [
                "artisan",
                "boost:mcp"
            ]
        }
    }
}

And yes, sail is up

[yahya-allouhaibi]

@pushpak1300 can you please take a screenshot of your raw config file and share it

[jw7712]

I had the same issue on linux, but the comments above helped me fix it.
I changed this:

{
    "mcpServers": {
        "laravel-boost": {
            "command": "/usr/bin/php8.4",
            "args": [
                "artisan",
                "boost:mcp"
            ],
            "env": {}
        }
    }
}

to

{
    "mcpServers": {
        "laravel-boost": {
            "command": "/usr/bin/php8.4",
            "args": [
                "/var/www/my-laravel-app/artisan",
                "boost:mcp"
            ],
            "env": {}
        }
    }
}

i was just using artisan without the full path, this was my original entry.
Using the full path to the artisan location did the trick.

[aykun1907]

I can confirm that It's most likely a path issue especially if you are trying to let it access a local package that was installed priorly.

[wangjia184]

It does not work for me even I configured absolute path, ( I also tried relative path and configures PATH env variables)

{
    "mcpServers": {
        "ida-pro-mcp": {
            "command": "D:\\IDAProfessional9.1\\python311\\python.exe",
            "args": [
                "D:\\IDAProfessional9.1\\python311\\Lib\\site-packages\\ida_pro_mcp\\server.py"
            ],
            "env": {}
        }
    }
}

Error: calling "initialize": invalid trailing data at the end of stream.

The same MCP server works in other IDE

[backstageel]

OK, this config worked for me:

{
  "mcpServers": {
    "laravel-boost": {
      "command": "docker",
      "args": [
        "exec",
        "-i",
        "enviro360-laravel.test-1",
        "php",
        "/var/www/html/artisan",
        "boost:mcp"
      ]
    }
  }
}

enviro360 is the name of my project

[kishwordulal1234]

same issue {
"mcpServers": {
"kali-tools": {
"command": "C:\Users\kishw\AppData\Local\Programs\Python\Python313\python.exe",
"args": [
"C:\Users\kishw\Desktop\zotak\mcp_server_fixed.py",
"--server",
"http://192.168.101.16:5000"
]
}
}
} i even gave it full python path still no any fix at first i used this {
"kali-tools": {
"command": "python",
"args": [
"C:\Users\kishw\Desktop\zotak\mcp_server.py",
"--server",
"http://192.168.101.13:5000"
]
}
}

i tried it is quider z.dev cursor vs code windsurf all work perfectly but this antigravity thing is not working i used this for all "kali-tools": {
"command": "python",
"args": [
"C:\Users\kishw\Desktop\zotak\mcp_server.py",
"--server",
"http://192.168.101.13:5000"
]
}
}

[KhaiHuynhVN]

Same error. My Custom MCP Server work perfect in Cursor. Please fix

[pushpak1300]

I suspect this issue is with the antigravity MCP client rather than Boost, since Boost already fully supports the MCP protocol, and if the client is not implementing it correctly we unfortunately cannot make it work from our side.

Edit: One more thing i realise even though antigravity agent doesn't support mcp correctly but underlying vscode mcp client works without any issue.(with sail with php and with docker)

[github-actions]

Thank you for reporting this issue!

As Laravel is an open source project, we rely on the community to help us diagnose and fix issues as it is not possible to research and fix every issue reported to us via GitHub.

If possible, please make a pull request fixing the issue you have described, along with corresponding tests. All pull requests are promptly reviewed by the Laravel team.

Thank you!

[3ddelano]

Yes this is an issue with how the antigravity mcp client handles the mcp connections on windows. For my python mcp server (unrelated to laravel) the below change fixed the issue:

import sys
if sys.platform == "win32":
    sys.stdout.reconfigure(newline="\\n")

[smraikai]

Same issue for me.

I get "Error: calling "initialize": EOF."

MacOS.

[samehdoush]

Same issue for me.

I get "Error: calling "initialize": EOF."
Windows 11