OVMS tools call for Gemma 4 E4B failed

I am setting up an OVMS for Linux, OpenCode and Gemma 4 E4B.
And I see that tools call request has some another tool call format:

Expected:

{ "tool_calls": [ { "type": "function", "function": { "name": "write", "arguments": "{"content": "TEXT", "filePath": "/absolute/path/file.txt"}" } } ] }

Got:

User

Try to save some small file first

Assistant (Build · ovms.gemma-4-e4b (local) · 7.1s)

{
"tool_calls": [
{
"name": "write",
"arguments": {
"filePath": "small_file.txt",
"content": "This is a small test file."
}
}
]
}

As you can see there are some differences in JSON. Is there a way to change/customize this without code change?

How do I run ovms:

ovms --model_name gemma-4-e4b
--model_path ./gemma-4-e4b-ov-int4
--target_device $DEVICE
--port 9080
--rest_port 8080
--cache_dir ./gemma-4-e4b-ov-int4/npu_cache
--log_level $LOG_LEVEL
--tool_parser gemma4

My config:

Ubuntu 24.04.5 LTS
6.17.0-1032-oem
Intel© Core™ Ultra 7 265H × 16

OpenVINO Model Server 2026.3.0.6f3df706b

Start with the OVMS tool-parser behavior selected by --tool_parser gemma4 and compare its response with the expected tool_calls format shown in the report. Reproduce the request using Gemma 4 E4B on Linux, determine whether configuration can change the format, and consider the issue done when the returned schema matches the expected format or the customization limitation is documented.