Frequently asked questions
Short, direct answers to the questions people ask most about Anomalous — cost, privacy, safety, requirements, and how it differs from other Mac tools.
General
Is Anomalous free?
Yes. The sensor that watches your Mac is free and open source. Detecting anomalies, learning your Mac's baselines, and reading the anomaly report never cost anything. Only the optional cloud "Get Help" triage is paid, where an escalation spends a few cents of a prepaid balance. The watching is free; only asking an expert cloud model to resolve a specific problem costs money. See Accounts, tokens & Get Help.
How is it different from Activity Monitor or iStat Menus?
Those tools are gauges: they show CPU, memory, GPU, and network and then stop, leaving you to be the analyst. Anomalous is the judge instead, described in its own materials as "Activity Monitor with a 'So what?' and 'Now what?' layer." It stays silent when nothing is wrong, and only when something genuinely is surfaces a plain-language card: what the process is, whether this is normal for it, why it is hot, and one safe thing to do. It is not a cleaner, not a dashboard, and never a chatbot.
Will it constantly nag me?
No. Silence is the default state and the brand. Most of the time the menu-bar glyph shows "All systems nominal" and says nothing. A finding has to clear a deliberately high confidence bar before it becomes a card or a notification; lower-confidence observations are kept quietly in a transparency panel rather than thrown at you.
Under the hood
Only findings scored >= 0.8 (high confidence) surface a card; medium (>= 0.5) and low are retained silently. No single statistical detector alerts on its own, corroboration between rules, magnitude, and machine-wide context together decide confidence. Multiple flags on one process collapse into a single card so you never get five notifications for one underlying event.
Privacy & safety
Is it safe to install?
Yes. The download is a signed and notarized macOS app, and the sensor is open source (Apache-2.0), so the code that composes every network payload is public and auditable. Trust is the product: the client is open specifically so you can read it instead of taking a promise on faith.
What data leaves my Mac?
Almost none, and nothing identifiable. Detection, baselines, judgment, your acknowledgments, and the journal all stay on the machine. Only three flows ever transmit: two are anonymous and opt-in (anomaly signatures and unknown-process lookups), and the third is the paid Get Help triage, the only one tied to your account, and only for billing and results. File paths, command-line arguments, usernames, and hostnames never leave your Mac.
Can I verify what was sent?
Yes. Before any payload goes on the wire, the exact bytes are written to a local send log you can open from Finder and diff against what the server says it received. Auditable beats approvable. See Privacy & transparency for how to read it.
Under the hood
Command lines are excluded everywhere because they routinely carry credentials, and anonymous signature timestamps are truncated to the hour to resist timing correlation. On the server, anonymous endpoints require no auth and have no user columns downstream, while triage sits behind Sanctum authentication, the two flows are structurally never conflated. The account token can never traverse cleartext to a remote host, and a shipped build can only be pointed at localhost. The sensor source is at github.com/msitarzewski/anomalous-mac; the public data corpus is at github.com/msitarzewski/anomalous-corpus (it may still be private today, but PRs are welcome).
Requirements
What do I need to run it?
A Mac and the free signed download. There is no account required to watch your Mac, detection, baselines, and the anomaly report run entirely on-device and offline. An account only comes into play if you choose to use the paid Get Help triage.
Does it slow down my Mac?
Anomalous is built to be quiet. It samples running processes roughly every 90 seconds, keeps its analysis on-device, and shows nothing while your Mac is behaving. It is a menu-bar app designed to sit in the background and stay out of the way, not a heavy always-scanning utility.
Do I need a special Mac for the AI explanations?
No. The detector that decides what is wrong runs everywhere; the on-device model only phrases the verdict in plain language. On Macs with Apple's on-device Foundation Models (macOS 26 and later) you get the model-written card; on Macs without it, the app degrades to a deterministic card built from its knowledge map. Either way the model is the explainer, never the detector, so it cannot invent a problem.
Do I need an account?
Only for paid Get Help. Account creation is invite-gated at launch, so you need a valid invite code. The Mac app registers with just your email plus the code and receives an account token; email is captured for receipts and balance recovery, not required to run the free sensor.
Billing
What does Get Help cost?
Each Get Help escalation charges a flat fee of about 50 cents from your prepaid balance. If an identical case has been resolved before and is cached, you are refunded 40 cents so it costs only 10 cents. You pay for a diagnosis, not for the service trying, if triage fails or cannot produce a real answer, the full charge is refunded automatically.
How do I add funds?
Your balance is prepaid. You add between $5 and $200 through a Stripe-hosted checkout page, so no card data ever touches Anomalous. The dashboard shows your balance and a recent-activity ledger. See your account for setup.
Why isn't my top-up showing up yet?
Starting a checkout does not move money, credit is applied only after Stripe confirms the payment via its webhook. That normally takes a moment; if your balance has not updated, the confirmation has not arrived yet. Crediting is idempotent, so a retried confirmation never double-credits you.
What happens if my balance is too low?
If you cannot afford the fee, the escalation is declined with an "insufficient balance" response and nothing is charged. Add funds and try again.
Under the hood
Your balance is never stored as an editable number; it is computed as the sum of signed cent-deltas in an append-only ledger (reasons: topup, triage_charge, refund, cache_discount, adjustment). The 50-cent charge is taken atomically under a per-user row lock at submission, so concurrent escalations cannot race one balance into unbounded paid inference; insufficient funds returns HTTP 402. Top-ups are credited exactly once, keyed on the Stripe checkout session id.