Legitimate interest assessment

Effective date: 22 October 2026

This assessment explains why Jack Runtime may collect usage telemetry and crash reports under legitimate interest (GDPR Article 6(1)(f)), and how we weigh that against your interests. The telemetry page lists every event and property.

1. Purpose of processing

Support. When you report a problem, the events show which version you ran, which harness was involved and where it failed, so we can fix it without asking you to reproduce it.
Reliability.Claude Code, Codex, Cursor and the other harnesses change their command-line tools often, sometimes weekly. Failures by harness and version tell us what broke before most people meet it.
Versions in use. Knowing which versions are still running helps us prioritise fixes and plan new releases for the versions people use.
Product decisions. Which features are used, and where people give up, decides what we build and fix next.

2. Necessity

Jack Runtime runs on your machine, so we have no server logs to learn any of this from. We considered the alternatives:

Opt-in telemetry reaches a small share of users, who are not typical of the rest; problems on the configurations nobody opted in from stay invisible.
Bug reports alone arrive late, lack the version and environment, and come only from people who take the time to write.
Crash reports alone show what crashed, not what silently failed or what works.

The events above are the least we need for these purposes. Telemetry stays on for that reason, with objection by email for anyone who has grounds to object.

3. Data minimisation

Only the events and properties on the telemetry page are sent. The product holds that list in its code and drops anything else.
Never sent: prompts, replies, chat text, file names, paths, the names you give things, your documents, command lines, environment variables or your email address.
Events are tied to a random install ID, made at first run and not derived from anything about you or your machine. Usage is reported as counts and outcomes, never content.
Your IP address is used only to work out your country and region, then discarded.

4. Safeguards

A notice the first time you use Jack Runtime says telemetry is on, what it collects and how to object.
Data goes through a relay on our own domain to PostHog and Sentry in their EU regions, which act as our processors.
Usage events are kept for one year and crash reports for 90 days.
We never sell the data, share it for advertising or use it for anything other than the purposes above.
Anyone can object by emailing [email protected] with the grounds relating to their particular situation (GDPR Article 21(1)). We review objections and reply by email. The data held under a random install ID is deleted on request.
On Enterprise, the company can turn telemetry off for everyone.

5. Balancing test

Our legitimate interest

Supporting the people who use Jack Runtime and keeping it working across harnesses that change underneath it. Without this data we would support people blind and learn about breakage from complaints.

Impact on you

Low. The data says how the product behaved, not what you worked on. It is not used to track you across websites, build an advertising profile or make decisions about you. Developer tools commonly report usage this way, and the first-run notice says so before any data matters.

You cannot switch telemetry off yourself outside Enterprise. Objection by email balances that: it is answered within one month, and an accepted objection stops collection and deletes the data held under a random install ID.

Conclusion

Our interest in supporting you and keeping Jack Runtime reliable is not overridden by your interests or rights, given how little is collected and the safeguards above. Legitimate interest is an appropriate basis for this processing.

6. Review

We review this assessment when the telemetry adds a new kind of data, and at least once a year. The date above shows the latest review.