An open-source CLI that fingerprints the structure of your API responses and alerts you the moment a field is silently removed or changes type — built for APIs an AI agent calls as tools.
A price changing, a name updating, a list being reordered — none of that is a schema break, and none of it triggers an alert. What does: a field disappearing, or changing type out from under you.
Register and check
# register your endpoint once ./telemetry register my-api GET api.example.com/v1/status \ --header "Authorization=env:MY_API_TOKEN" # first run sets the baseline automatically ./telemetry check my-api
What an alert looks like
{
"endpoint": "my-api",
"severity": "breaking",
"field": "user.email",
"change": "field removed"
}
Small, focused, and honest about what it is — a schema-diffing checker, not a general uptime monitor.
Field names, types, and presence are fingerprinted and diffed — never the data values themselves.
Breaking, warning, and info, so you can tell a real break from routine noise at a glance.
Optional outgoing webhook notifications when something actually breaks.
Designed around the APIs an AI agent calls as tools, where a silent shape change breaks a tool call even though the endpoint still looks healthy.
Runs from one SQLite file. No required dependencies — a bundled urllib fallback if you skip installing
requests.
MIT licensed. Read the code, self-host it, or contribute — nothing is hidden behind a paywall to see how it works.
For anyone who wants a hosted, multi-tenant version instead of running the CLI themselves.