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Macaw-4bit-MLX

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Macaw-4bit-MLX generates the correct first Pythonic tool call through MLX-LM 0.31.3, but after a successful role:tool result it repeats the identical call indefinitely. This persists when the result is formatted as read_file: created-on-host, when the tools array is removed, and when tool_choice is set to none. Adding "tool_parser_type":"pythonic" was necessary for structured OpenAI output.

HTTP_STATUS=$(
curl -sS
-o /tmp/macaw-roundtrip-no-tools-response.json
-w '%{http_code}'
http://127.0.0.1:8138/v1/chat/completions
-H 'Content-Type: application/json'
--data-binary @/tmp/macaw-roundtrip-no-tools.json
)

echo "HTTP status: $HTTP_STATUS"
jq . /tmp/macaw-roundtrip-no-tools-response.json
HTTP status: 200
{
"id": "chatcmpl-dc6d4d94-c6c1-4e85-8683-6290d797a21b",
"system_fingerprint": "0.31.3-0.32.0-macOS-27.0-arm64-arm-64bit-Mach-O-applegpu_g16g",
"object": "chat.completion",
"model": "default_model",
"created": 1786038850,
"choices": [
{
"index": 0,
"finish_reason": "tool_calls",
"message": {
"role": "assistant",
"tool_calls": [
{
"function": {
"name": "read_file",
"arguments": "{"path": "/workspace/host-test.txt"}"
},
"type": "function",
"id": "f2ce30fa-9e1b-4d6d-b81d-14f11c601610"
}
]
}
}
],
"usage": {
"prompt_tokens": 71,
"completion_tokens": 17,
"total_tokens": 88,
"prompt_tokens_details": {
"cached_tokens": 0
}
}
}

HTTP_STATUS=$(
curl -sS
-o /tmp/macaw-roundtrip-tool-none-response.json
-w '%{http_code}'
http://127.0.0.1:8138/v1/chat/completions
-H 'Content-Type: application/json'
--data-binary @/tmp/macaw-roundtrip-tool-none.json
)

echo "HTTP status: $HTTP_STATUS"
jq . /tmp/macaw-roundtrip-tool-none-response.json
HTTP status: 200
{
"id": "chatcmpl-45ac9601-5714-4114-afbc-b4524945020f",
"system_fingerprint": "0.31.3-0.32.0-macOS-27.0-arm64-arm-64bit-Mach-O-applegpu_g16g",
"object": "chat.completion",
"model": "default_model",
"created": 1786038868,
"choices": [
{
"index": 0,
"finish_reason": "tool_calls",
"message": {
"role": "assistant",
"tool_calls": [
{
"function": {
"name": "read_file",
"arguments": "{"path": "/workspace/host-test.txt"}"
},
"type": "function",
"id": "4cb4f39a-5fa8-4720-a6fe-96633abe379e"
}
]
}
}
],
"usage": {
"prompt_tokens": 136,
"completion_tokens": 17,
"total_tokens": 153,
"prompt_tokens_details": {
"cached_tokens": 0
}
}
}