The short version: in the default mode, nothing does. Read the long version anyway — it is honest, and it should be.
Last updated: September 2026
Who we are
Context Fence is a product of Synthrun. Synthrun builds and maintains the Context Fence proxy, this website, the Homebrew tap that distributes the macOS build, the Windows release pipeline, and — one day — the hosted control plane. Everything in this policy covers all of those. If a service is ours, this policy applies; if it is not listed here, it is not part of the product.
Local-only mode collects nothing
In the default mode the proxy runs entirely on your machine. No telemetry, no crash reports, no policy uploads, no analytics from the product itself. We cannot see your tool calls because they never reach us. The audit log, the policy file, and every secret-shaped value the fence strips — all of it stays on your disk.
What never leaves the machine
- —Every tool call the agent makes, allowed or denied
- —The audit log rows and the rules that decided them
- —Your cf.policy.yml — we never see a policy file
- —Secrets the fence strips before they reach a model or a tool
- —Anything the model, your tools, or the proxy print to a local log
What the website sees
This site uses Google Analytics to count visits and see which pages people read. GA sets cookies and we see aggregate numbers only: rough visitor counts, popular pages, broad geography. We do not see your identity through it, and we do not try to. The downloads page itself reads a public release manifest from GitHub — that is a public file any visitor can read, and it contains only version numbers, file sizes, and checksums.
Do Not Track and Global Privacy Control
We honor Global Privacy Control as a decline of analytics: with the signal present, analytics stays off and the customize panel says so. Do Not Track headers are treated the same way. Essential storage is unaffected — the site cannot remember your theme or your choice without it.
International transfers
The product keeps everything on your machine, so there is nothing to transfer. The only cross-border processing is Google Analytics, and only after you opt in: Google may process aggregate visit data on infrastructure outside India, including the US, under its own terms. No other website data leaves the region by design — email replies stay with the founders.
The early access form
Submitting the early access form sends us your email address. We use it exactly once: to reply about access. No list rental, no third-party marketing, no drip campaigns. The reply comes from the founders directly, within 4 business hours. If you later ask us to delete it, we delete it — one message is enough.
Hosted control plane (not yet available)
When it ships, opting in syncs the audit log to our infrastructure so a team can review it in one place. That is the explicit trade: you send us the log, we keep it for you. The sync is off by default, the log remains on your machine regardless, and the local mode keeps collecting nothing. Fleet policies, audit sync, and Slack alerting are planned features of that plane — none of them exist in the default path.
What we never collect
- —Children's data — the product is for developers; we do not knowingly collect anything from anyone under 13
- —Biometrics, precise location, or contacts
- —Your chat history, prompts, or agent conversations
- —Model outputs, generated code, or anything the agent produces
- —Credentials or secrets — the fence's entire job is stopping those from leaking
Security
The product is local-first by construction: no telemetry endpoint, no control plane in the default path, no dependency on a model provider to enforce anything. The macOS build is ad-hoc signed and the Windows build is unsigned by design; both are published with their sha256 checksums so you can verify what you installed. We cannot claim a cloud we do not have.
Retention
Email addresses from the early access form are kept until you ask us to delete them. Website analytics are aggregate counters; there is no per-person record to retain. The audit log is yours — retention is your decision, on your disk.
Your rights
Ask us anything: what we hold about you, why, and for how long. In local mode there is no account to delete — uninstalling the app deletes everything but your own files. If the hosted plane exists by the time you read this, the same rights apply to your synced copy.
Changes to this policy
If this policy changes, the date at the top changes and this page is the notice. We will not quietly change what crosses the fence. For the default, local mode: nothing does.
Follow the packets
Pick a mode and watch what actually leaves your machine. This is the whole policy in one drawing.
Questions?
Use the early access form on the home page and say it is about privacy. The founders answer it directly — no support desk, no ticket queue.