Shakedown runs entirely on the user's own Mac. The surface area is small: a handful of short shell scripts plus inline Python heredocs, no external dependencies beyond what ships with macOS, and no daemons or persistent components. The default ./run makes no outbound network calls and runs no third-party code. Everything is local and auditable: the scripts are pure bash and Python, no minified or obfuscated code, short enough to read end to end in a few minutes. Two opt-in exceptions, both off by default and disclosed below: the --gpu phase compiles a small Metal kernel at runtime, and the --llama phase clones and builds llama.cpp and reaches the network.

• Verification/scripts/thermal-load.sh invokes sudo powermetrics for read-only thermal, CPU-frequency, and ambient-temp sampling. This is the only script that requires elevation, and powermetrics is the only command run under sudo.
• No other script asks for, requires, or uses elevated privileges.
• All other data collection is unprivileged: SHA-256 over a fixed in-memory 1 MB buffer for the CPU workload (deterministic; no I/O), hardware facts via system_profiler / ioreg / sysctl, and battery state via ioreg AppleSmartBattery.
• Writes are confined to the repo's Reports/ directory and short-lived tempfiles under /var/folders/.../shakedown-* (the system per-user temp area). Nothing is written elsewhere.
• The default ./run makes no outbound network requests. The opt-in --llama phase is the sole exception (it clones llama.cpp and may download a model); see below. Reports stay on the local disk unless the user chooses to share them.

Three phases go past "interpreted, offline" scripts. The first is on by default but never touches the network; the other two are opt-in and off unless you ask for them. Nothing pre-compiled is ever shipped in the repo.

• Phase 12 memory bandwidth (default). memory-bandwidth.sh prefers a vendored STREAM triad: it compiles stream-triad.c with the clang from the Command Line Tools, runs it, and deletes the binary. The C source is in the repo and short enough to read. No network, no shipped binary, no privileges. If clang is unavailable it falls back to the pure-Python memmove proxy.
• --gpu (opt-in, offline). gpu-variance.sh compiles a small Metal compute kernel with swiftc at runtime. The Metal and Swift source is inline in the script's heredoc; read it before running. The compiled binary lives in a per-user tempfile deleted on exit, the kernel runs read-mostly FMA math over a scratch buffer, and it makes no network calls. Skips cleanly if swiftc or a Metal device is unavailable.
• --llama (opt-in, reaches the network). This is the only phase that leaves the machine and runs third-party code. llama-bench.sh clones llama.cpp at a pinned ref into ~/.cache/shakedown/llama, builds it with cmake, may download a small GGUF model (a pinned LLAMA_MODEL_URL, or a local LLAMA_MODEL you provide), and runs llama-bench. It is off unless you pass --llama, and it skips cleanly when git / cmake / the network / a model is unavailable. The clone is pinned and the cache is reused, so you can audit exactly what was fetched. The auto-download is not integrity-checked unless you set LLAMA_MODEL_SHA256 (a complete but corrupted or tampered download would otherwise be cached and run); for a guaranteed-consistent model, point LLAMA_MODEL at a local .gguf you trust. To keep the run fully offline and free of third-party code, simply don't pass --llama.

If you submit a report to the (planned) hosted aggregator:

• Serial numbers are SHA-256 hashed by default. inventory.sh and battery.sh emit serial_hash instead of the raw serial. The plaintext is included only if you set INCLUDE_PLAINTEXT_SERIAL=1. Even then, ./run keeps the plaintext in the local copy only and never writes it to the submission copy.
• The hash is obfuscation, not anonymization. Apple's serial space has limited entropy (~10⁸ combinations per chassis SKU); a determined operator could rainbow-table the original. Use the hash for deduplication assumptions, not untraceability. A future aggregator deployment should rotate to HMAC-SHA-256 with a deployment-secret salt. See Reports/SCHEMA.md.
• _raw_* fields in the inventory and battery JSON contain full system_profiler / ioreg dumps that may include paired Bluetooth device IDs, Wi-Fi SSIDs, USB device serials, and other environment fingerprints. ./run strips these from the submission copy. They remain in Reports/local/<filename>.json (gitignored) for your own debugging.
• store_location, purchase_date are null by default and only populated if you opt in.
• submission_safe: true is the orchestrator's assertion that none of the above leaked through. Always check it before submitting.

If you find a security issue in Shakedown, please report it privately rather than opening a public issue:

• Open a private security advisory at https://github.com/ugglr/mac-shakedown/security/advisories/new.

Please include the affected script(s), macOS version, and reproduction steps. A response should arrive within a few days.