AFM — local AI infrastructure for Apple Silicon

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What's new

AFM v0.9.17

AFM turns an Apple Silicon Mac into a private, OpenAI-compatible AI server. Run Hugging Face MLX models or Apple’s on-device Foundation Model, then connect the clients and SDKs you already use.

• Native Swift executable—no Python runtime for serving
• Local inference—no cloud account or API key
• Chat, streaming, tools, structured output, reasoning, and logprobs
• Vision OCR, speech, embeddings, and a built-in WebUI
• Prefix caching, concurrent decode, speculative decoding, and metrics
• Importable Swift packages for apps that need in-process inference

AFM is for Apple Silicon Macs running current macOS/Xcode toolchains. MLX model weights download from Hugging Face the first time you use them.

Install

Note

Stable v0.9.17 is the recommended release. It adds automatic Qwen 3.8 MTP sidecar discovery and quant-matched download behavior, plus expanded Qwen 3.8 tool-calling qualification. Install afm-next only to preview changes made after v0.9.17.

The qualified nightly and v0.9.17 are essentially the same build. Nightly nightly-20260816-bc343f6 was promoted to this stable release; the differences are release versioning and distribution packaging, not runtime functionality. Use the stable release unless a newer nightly explicitly lists post-v0.9.17 changes you need.

	Stable (v0.9.17)	Nightly (afm-next)
Homebrew	brew install scouzi1966/afm/afm	brew install scouzi1966/afm/afm-next
pip	pip install macafm	pip install --extra-index-url https://maclocal-ai.pages.dev/afm/wheels/simple/ macafm-next
Release notes	v0.9.17	Latest nightly

Install a previous version

Older stable releases are kept as pinned formulae in the Homebrew tap and as version-pinned wheels on PyPI. This is useful for reproducing an issue against a specific build or rolling back without waiting for a new release.

Homebrew (pinned stable formulae): afm@<version> — available for 0.9.0, 0.9.1, and 0.9.3–0.9.10.

brew install scouzi1966/afm/afm@0.9.10
brew uninstall afm
brew link afm@0.9.10
afm --version

Homebrew (pinned nightly formulae): afm-next@<full-version> — for example, afm-next@0.9.15-next.20260808.e70cc52. See the Homebrew tap for available pinned nightlies.

brew install scouzi1966/afm/afm-next@0.9.15-next.20260808.e70cc52

pip (version-pinned wheels): install any published release by version.

pip install macafm==0.9.10
pip install --extra-index-url https://maclocal-ai.pages.dev/afm/wheels/simple/ \
  macafm-next==0.9.15.dev20260808

Start in two minutes

brew install scouzi1966/afm/afm

# Start a small MLX model and open the WebUI
afm mlx -m Qwen3-0.6B-4bit -w

AFM is now listening at http://127.0.0.1:9999/v1.

curl http://127.0.0.1:9999/v1/chat/completions \
  -H 'Content-Type: application/json' \
  -d '{
    "model": "Qwen3-0.6B-4bit",
    "messages": [{"role": "user", "content": "Explain unified memory in one paragraph."}],
    "stream": false
  }'

Or use Apple’s on-device model:

afm -w

Choose your runtime

Runtime	Best for	Start it
MLX	Open models, VLMs, agent controls, performance tuning	afm mlx -m <model>
Apple Foundation Models	Zero-download system model and .fmadapter LoRA adapters	afm
DwarfStar	Compatible fixed-schedule Metal checkpoints	afm mlx -m <owner/repo> (auto-resolved) or afm mlx -m <checkpoint.gguf> --mlx-runtime dwarfstar
Gateway	One model list for Ollama, LM Studio, Jan, and other local servers	afm --gateway

Model IDs without an organization default to mlx-community, so Qwen3-0.6B-4bit and mlx-community/Qwen3-0.6B-4bit both work.

Why AFM works well for agents

AFM is built for multi-turn, tool-using clients—not only chat demos.

Capability	What it gives you
Native tool formats	Auto-detection for JSON, Qwen XML, Gemma, GLM, Kimi, MiniMax, LFM2, and related formats
Tool choice	auto, none, required, and named-function forcing
Streaming tool deltas	OpenAI-style tool-call chunks while ordinary content continues to stream
Structured output	json_object, json_schema, and token-level xgrammar enforcement when enabled
Reasoning extraction	<think> and harmony analysis channels mapped to reasoning_content
Determinism and inspection	seed, logprobs, top_logprobs, request IDs, tracing, and raw-parser mode
Long-running reliability	Cancellation, Retry-After, token counting, fair concurrent queues, and Prometheus metrics
Prefix reuse	Radix-tree KV caching for stable system prompts and multi-turn agent loops

Pick a tool-calling mode

• Native (default): AFM detects the model’s own format and uses the narrowest parser. Use this for parity checks and benchmarks.
• Repair: add --tool-call-parser afm_adaptive_xml for JSON-in-XML fallback, type coercion, nullable-schema handling, and fuzzy tool-name matching. Add --fix-tool-args when a model renames arguments.
• Raw: add --tool-call-parser none to return the model’s tool markup as ordinary assistant content.

See MLX tool-calling modes for examples and benchmark guidance.

Connect an existing client

Most OpenAI-compatible clients need only a base URL and a placeholder API key:

Base URL: http://127.0.0.1:9999/v1
API key:  x

Copy-ready guides:

OpenCode · OpenClaw · Cline · Continue · Aider · Cursor · Hermes

OpenClaw users can also generate a provider block directly:

afm mlx -m Qwen3-Coder-Next-4bit --openclaw-config

API surface

Method	Endpoint	Purpose
POST	/v1/chat/completions	Chat, SSE streaming, tools, reasoning, structured output, logprobs
GET	/v1/models	Active model and gateway model discovery
POST	/v1/embeddings	Apple NaturalLanguage embeddings for RAG and semantic search
POST	/v1/vision/ocr	OCR, tables, barcodes, classification, saliency, and PDFs
POST	/v1/audio/transcriptions	On-device speech-to-text
POST	/v1/audio/speech	Text-to-speech using installed Apple voices
POST	/v1/tokenize	vLLM-compatible tokens and counts for the loaded MLX model
POST	/v1/count_tokens	Anthropic-style input token count
POST	/v1/batch/completions	Multiplex up to 64 completions over SSE
POST	/v1/chat/completions/{id}/cancel	Cancel an in-flight generation
GET	/metrics	Prometheus queue, token, throughput, and timing metrics
GET	/openapi.json	OpenAPI description
GET	/docs	Interactive API reference served by AFM

AFM also implements OpenAI-style file and batch-job endpoints under /v1/files and /v1/batches when the MLX batch service is active.

Apple-native tools

The CLI and HTTP server expose useful system frameworks without another service.

# OCR text or a table from an image/PDF
afm vision --file invoice.pdf --table

# Other Vision modes: text, table, barcode, classify, saliency, auto
afm vision --file photo.heic --mode classify --format json

# Speech recognition
afm speech transcribe --file meeting.wav --format srt

# Text to speech
afm speech synthesize "Hello from AFM" --voice nova --output hello.aac

# Dedicated OpenAI-compatible embeddings server (default port 9998)
afm embed

For vision-language models, add --vlm and pass one or more files with --media.

Performance controls

Defaults are a good starting point. Use these when the workload calls for them:

# Reuse prompt KV across requests
afm mlx -m <model> --enable-prefix-caching

# Save memory on long context
afm mlx -m <model> --kv-bits 8

# Fair-queue concurrent requests through one model
afm mlx -m <model> --concurrent 4

# Strict tool/JSON schemas with xgrammar
afm mlx -m <model> --enable-grammar-constraints

# Per-request device, memory, timing, and bandwidth estimates
afm mlx -m <model> --gpu-profile -s "Explain Metal kernels"

Supported checkpoints can also use speculative decoding:

• --mtp for compatible Qwen models. Qwen3.8 automatically prefetches the separately published MTP head matching the base checkpoint's quantization; use --mtp-model <repo-or-path> to override it.
• --eagle3 <drafter-directory> for supported dense Gemma4 models
• --dspark-support <support.gguf> for compatible DwarfStar DSpark workflows

Read decode optimizations before choosing a checkpoint or interpreting benchmark results.

Sampling and response controls

The MLX backend supports temperature, top_p, top_k, min_p, repetition_penalty, presence_penalty, seed, stop, logprobs, and top_logprobs.

Useful server defaults:

# Apply one JSON schema when requests omit response_format
afm mlx -m <model> \
  --guided-json '{"type":"object","properties":{"answer":{"type":"string"}},"required":["answer"]}' \
  --enable-grammar-constraints

# Disable model reasoning/thinking
afm mlx -m <model> --no-thinking

# Pin chat-template keyword arguments
afm mlx -m <model> --chat-template-kwargs '{"enable_thinking":false}'

Use AFM as a Swift package

The repository publishes focused Swift Package Manager products:

• AFMKitCore — provider contracts and core types
• AFMOpenAICompat — OpenAI-compatible request/response types
• AFMKitMLX — MLX model loading and inference
• AFMKitFoundationModels — Apple Foundation Models backend
• AFMKitFoundationModels27 — macOS 27 provider protocol adapters
• AFMKitFoundationModels27DwarfStar — opt-in DwarfStar macOS 27 adapter
• AFMKitDwarfStar — DwarfStar runtime integration
• AFMKitServices — vision, speech, and embedding services
• AFMKit — high-level headless inference facade
• AFMServer — Vapor HTTP layer
• afm — CLI executable

dependencies: [
    .package(
        url: "https://github.com/scouzi1966/maclocal-api.git",
        branch: "main"
    )
]

Start with the AFMKit public API guide and the consumer examples.

Build from source

git clone https://github.com/scouzi1966/maclocal-api.git
cd maclocal-api
./build.sh

The complete build initializes submodules, applies AFM-owned vendor patches, builds the WebUI, rebuilds Metal resources when the toolchain is available, and creates the release executable. Add --install to install it on your PATH.

Requirements

• Apple Silicon Mac
• macOS 26 or newer for the complete feature set
• Xcode 27 for development builds
• Disk and unified memory appropriate for the model you choose

Small 0.6B–4B quantized models are the easiest way to confirm a setup. Large 30B-class models need substantially more unified memory.

Documentation map

• Client setup guides
• MLX tool calling
• Vision OCR API
• Embeddings API
• Apple-native endpoints
• Model path resolution
• Decode optimizations
• AFMKit public API
• Parameter combinations and use cases
• Supported model architecture catalog
• Roadmap

Contributing

Issues, reproducible test cases, documentation improvements, and model-compatibility reports are welcome. Read AGENTS.md and CLAUDE.md before changing build, test, or vendored integration code.

If AFM is useful to you, star the repository. You may also like Vesta AI Explorer, a full-featured native macOS AI app.

License

MIT