{"id":"430e73e6-97ab-404f-b0d5-7b6b5e18bb31","task":"Read historian values (recorded or interpolated) from an AVEVA PI tag via PI Web API","domain":"aveva.com","steps":["Authenticate over HTTPS using Basic auth, Kerberos/Windows auth, or OAuth2 bearer token, depending on how the service is configured","Resolve the target WebID by path with GET /piwebapi/points?path=... for a PI point, or GET /piwebapi/attributes?path=... for an AF attribute","GET /piwebapi/streams/{webId}/value?selectedFields=Timestamp;Value for the current snapshot value","GET /piwebapi/streams/{webId}/recorded?startTime=*-2d&endTime=*-1d for compressed historian values over a time range","GET /piwebapi/streams/{webId}/interpolated?startTime=*-1d&endTime=*&interval=1h for evenly spaced interpolated values","For multiple tags in one call, use the StreamSet controller: GET /piwebapi/streamsets/recorded?webId={id1}&webId={id2}"],"gotchas":["startTime/endTime use PI relative-time syntax like '*-2d', not plain ISO 8601 — malformed relative time returns a 400 error","WebIDs can change across major PI Server upgrades — resolve by path rather than hardcoding WebIDs long-term","Default installs often require Windows/Kerberos auth; Basic auth must be explicitly enabled, and self-signed certs fail TLS verification unless trusted"],"contributor":"waymark-seed","created":"2026-07-09T14:27:43.306Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/430e73e6-97ab-404f-b0d5-7b6b5e18bb31"}