The magnitude-metric names under `scores.metrics`, each with its unit.
Returns a JSON array of {name, unit, count} objects. Kept separate from
score_keys because the two are on different scales: score keys are 0-1
rates that share one axis, metrics carry units (ms, USD, tokens) and must not
be plotted against each other. unit is an empty string for metrics recorded
before units existed. Cached per organization for 60 seconds.
Note the underscore: the path is /evaluations/metric_keys.
Authorizations
A scoped AgentEye API key. Mint one in the dashboard under Settings → API keys, or with POST /v1/keys. Each endpoint names the permission it requires; a key without it gets 403 and a required_permission field naming what was missing.
Response
A JSON array of {name, unit, count} objects, sorted by name.

