get_runtime_capabilities was returning `accelerators = ["cpu",
"vulkan"]` and `whisper.supports_gpu = true` regardless of build
config or runtime state. On a macOS build it falsely advertised
"vulkan" (the backend actually resolves via MoltenVK as Metal); on a
whisper-disabled build it claimed GPU support for an engine that
hadn't been linked.
Added `compose_accelerators(whisper_enabled, loader_available, target)`
— a pure helper that always emits "cpu" first and appends the
platform-appropriate GPU name only when whisper is compiled in AND the
Vulkan loader resolves. `supported_accelerators()` wraps it with the
live `cfg!(feature = "whisper")`, loader probe, and target OS.
`get_runtime_capabilities` now calls `supported_accelerators()` and
sets `whisper.supports_gpu = cfg!(feature = "whisper")`. Parakeet
stays CPU-only.
Five tests in `commands::models::tests` cover the permutation matrix:
whisper on/off, loader present/missing, macOS vs other. Both feature
configurations (`--features whisper` and `--no-default-features`)
build and pass tests.
Macos Metal-loader resolution on real hardware stays on the
ship-gate checklist — the detection logic is verifiable from Linux
but runtime behaviour is not.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Jake
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