lmd

A single-binary LM Studio replacement for Apple Silicon.

lmd owns every part of the local-LLM workstation experience:

• broker on 127.0.0.1:5400 exposes an OpenAI-compatible HTTP API over any MLX model on disk
• JIT model routing spawns a dedicated SwiftLM child per model, allocates ports from a pool, shuts them down under memory pressure
• sensor sampling to memory.jsonl (was swiftmon) for historical thermal/battery/power data
• fan control via the macos-smc-fan privileged helper (XPC), scaled by in-flight request count so fans ramp gradually during inference and cool down slowly after
• multi-tab TUI (monitor, library, bench, events) rendered in raw terminal mode
• benchmark orchestrator for long-running model comparison jobs

One subsystem for unified logs (io.goodkind.lmd). One daemon (lmd-serve). One interactive tool (lmd-tui).

Install

make install

This:

1. Builds release binaries for all targets.
2. Copies them to ~/.local/bin/ (override with PREFIX=/opt/...).
3. Writes ~/Library/LaunchAgents/io.goodkind.lmd.serve.plist from the template with your install path substituted in.
4. launchctl bootstraps the agent into the current GUI session.

The broker starts running immediately and at every subsequent login.

Binaries

Binary	Role	Lifecycle
lmd	Dispatcher. lmd serve, lmd tui, lmd bench, lmd qa execs the right sibling.	Short-lived (the user runs it).
lmd-serve	Broker + sensor sampler + fan control.	24/7 LaunchAgent.
lmd-tui	Interactive dashboard (monitor / library / bench / events tabs).	Foreground while the user wants it open.
lmd-bench	Benchmark orchestrator. Long runs that survive terminal close.	Foreground or detached via nohup.
lmd-qa	TUI QA harness for CI (three drivers: tmux, pty, iTerm).	CI only.

The broker on 5400 speaks the OpenAI API. Point Cursor, humanify, or anything else at http://127.0.0.1:5400 and it just works.

Environment

Defaults live in deploy/io.goodkind.lmd.serve.plist.example. All lmd-serve environment variables:

Var	Default	Meaning
LMD_HOST	127.0.0.1	Broker bind host.
LMD_PORT	5400	Broker bind port.
LMD_BUDGET_GB	80	Max GB of models resident at once. Evictions happen above this.
LMD_IDLE_MINUTES	15	After this many minutes idle, unload a chat (SwiftLM) model.
LMD_EMBEDDING_IDLE_MINUTES	60	Idle timeout for in-process MLX embedding backends (often longer than chat).
LMD_SAMPLE_INTERVAL	15	Seconds between sensor samples.
LMD_DATA_DIR	~/Library/Application Support/io.goodkind.lmd	Where memory.jsonl lands.
LMD_SWIFTLM_BINARY	~/Sites/SwiftLM/.build/arm64-apple-macosx/release/SwiftLM	SwiftLM inference engine to spawn.

The client-side dispatcher also reads LMD_HOST and LMD_PORT for lmd status, lmd load, lmd unload, etc.

Embeddings

POST /v1/embeddings accepts an OpenAI-shaped body (model, input as a string or array of strings, optional encoding_format, must not set stream).

Models are classified as chat or embedding when the catalog scans disk: sentence_bert_config.json or modules.json, config.json architectures (BERT family, Snowflake Arctic Embed, and similar), model_type hints, plus name patterns such as embed or bge. See ModelCatalog.inferModelKind in SwiftLMRuntime.

GET /v1/models and GET /swiftlmd/loaded include a kind field per entry (chat or embedding). Chat requests against an embedding id return HTTP 400.

Embedding inference uses MLXEmbedders in process (SwiftLMEmbed, weights from the same directories as chat models). Example model id style: Snowflake/snowflake-arctic-embed-l when that layout exists under ~/.lmstudio/models.

Smoke test from the dispatcher: lmd embed -h then lmd embed -m <id> -t "hello".

Observability

Everything structured flows through os.Logger under subsystem io.goodkind.lmd:

# Live tail.
log stream --subsystem io.goodkind.lmd --info

# Last hour with category filter.
log show --predicate 'subsystem == "io.goodkind.lmd" AND category == "FanCoordinator"' --last 1h

# NDJSON for parsing.
log show --subsystem io.goodkind.lmd --last 30m --style ndjson

Data artifacts (memory.jsonl, bench results/*.json) are separate from logs. See plan/logging-migration.md.

Develop

SwiftPM pulls macos-smc-fan from https://github.com/agoodkind/macos-smc-fan.git on branch main. A normal clone of this repo is enough for swift build.

make build              # release build of everything
make test               # unit + snapshot + integration tests
make tui-qa             # interactive TUI QA: tmux + pty + iTerm drivers
make log-audit          # enforce the Apple-native logging policy
make run-tui            # launch the TUI in foreground
make run-serve          # run the broker in foreground (bypasses launchd)
make restart-serve      # pick up a new broker binary under launchd
make uninstall          # remove binaries + LaunchAgent

Layout

lmd/
  Sources/
    AppLogger/           shared os.Logger + swift-log bridge
    SwiftLMCore/         model descriptors, shared types
    SwiftLMBackend/      SwiftLM child-process lifecycle
    SwiftLMEmbed/        MLX embedding backends (MLXEmbedders)
    SwiftLMRuntime/      router, bench config + orchestrator, fan + event bus
    SwiftLMMonitor/      macmon client, sensor sampler, battery reader
    SwiftLMTUI/          tab protocol, panels, ANSI + input parsers
    lmd/                 dispatcher (lmd <subcommand>)
    lmd-serve/           broker + sampler + fan daemon
    lmd-tui/             interactive dashboard
    lmd-bench/           benchmark runner
    lmd-qa/              three-driver TUI QA harness
  Tests/
    SwiftLMTUITests/     tab render snapshots
    SwiftLMRuntimeTests/ bench, router, fan logic
    IntegrationTests/    binary launch + SIGINT
    Fixtures/            shared inputs (log categories, tuiqa coverage)
  deploy/
    io.goodkind.lmd.serve.plist.example   LaunchAgent template
    homebrew/                              brew formula
  plan/
    logging-migration.md                   Apple-native logging policy
    GENERALIZATION.md                      architecture roadmap

Related projects

• SwiftLM upstream MLX inference engine; lmd-serve spawns one child per loaded model.
• macos-smc-fan Swift package linked by FanCoordinator for XPC to the privileged helper (install the helper daemon from that repo).
• fancurveagent the LaunchAgent that owns fans when lmd-serve is not running. lmd-serve boots it out on takeover and re-bootstraps it on release.