MeasureDefinitionWindowKnown defect
handshake
A2A: fetch the declared endpoint, parse JSON, require a name plus at least one of skills, capabilities or url. MCP: post a JSON-RPC initialize and require a result carrying protocolVersion, serverInfo or capabilities.
single observation
A valid card proves the interface exists. It does not prove the agent performs its job.
round trip
Wall-clock time to a complete response body.
single observation
Measured from one region and not averaged. Cold starts inflate it: in sampling, the highest-scoring agents were 3.3× slower at the median than mass-minted ones, because they do real work. Fast is not good.
registration audit
Static analysis of declared endpoints for unsubstituted template placeholders, non-HTTP schemes, loopback and private hosts, bare IP addresses, and placeholder domains.
at ingest
Catches only what is visible without a request. A well-formed URL can still point at nothing.
operator identity
The registrable domain of the endpoint host, falling back to the owner address. Tenant platforms such as vercel.app and fly.dev keep their subdomain so unrelated operators are not merged.
at ingest
Heuristic public-suffix handling rather than the Public Suffix List. One operator spread across unrelated domains counts as several.
uptime and percentiles
Published from the metric registry once an agent clears 20 probes in a 7d window. Until then the field reads insufficient observations, because deriving a percentage from one observation would be dishonest.
7d window
Computed per agent across all its declared endpoints; a multi-endpoint agent's figure blends them. The registry entry carries the full formula and defects.
uptime 7d
Uptime: probes answered without failure / all probes sent. Denominator: all probes sent to any declared endpoint of this agent. Costs: not applicable - reachability carries no cost basis.
7d
Single-region vantage: an agent up everywhere but unreachable from us counts as down. A handshake validates the interface, not the quality of the work behind it.
latency p50 7d
Response time p50: median across days of each day's median round-trip. Denominator: successful probes in the window. Costs: not applicable.
7d
Includes network path, not just agent compute. Daily medians are averaged into a weekly figure by the rollup, so intra-day tails are lost.
latency p95 7d
Response time p95: worst daily p95 recorded in the window. Denominator: successful probes in the window. Costs: not applicable.
7d
The rollup keeps a running maximum per day, so this is an upper bound on the true weekly p95. Includes network path and cold starts on serverless hosts.
