GPT-OSS

10 MLX aliases · OpenAI's GPT-OSS 20B & 120B — MXFP4 / 4 / 8-bit · Harmony-native tool calling.

OpenAI's GPT-OSS line in MLX form — both the 20B and the 120B in MXFP4 / 4-bit / 8-bit quants, plus the safeguard-tuned 20B. Harmony-native tool calling (use the harmony tool-call parser) and Harmony reasoning streams. mxfp4-q8 is the recommended-by-OpenAI low-bit format — the 20B runs comfortably on a 32 GB Mac; the 120B wants a Mac Studio with 96 GB+.

family

GPT-OSS

aliases

10

lines

1

install

rapid-mlx serve <alias>

OpenAI base URL

http://localhost:8000/v1

GPT-OSS 20B & 120B · 10 aliases

20B and 120B in MXFP4 / 4-bit / 8-bit, plus the safeguard-tuned 20B. mxfp4-q8 is the recommended-by-OpenAI low-bit format. Harmony-native tool calling + Harmony reasoning streams.

parser: harmony

Notes & caveats

• 100% tool-call format compliance — Harmony was designed end-to-end for tools.
• 20B-mxfp4-q8 is the everyday pick; step up to 120B-mxfp4-q8 on 96 GB+ unified memory.
• Reasoning streams via the harmony reasoning parser into reasoning_content on /v1/responses.

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