# Authoritative sources

- Last verified: 2026-07-19
- Review cadence: every 6 months
- Refresh triggers: OGC standard revision or a routed skill changes its interface contract

## Canonical sources

- [OGC standards catalog](https://www.ogc.org/standards/) — current geospatial interoperability standards.
- [EPSG Guidance Notes](https://epsg.org/guidance-notes.html) — authoritative coordinate reference and operation guidance.
- [Agent Skills specification](https://agentskills.io/specification) — portable skill structure and progressive disclosure.

The orchestrator does not replace specialist sources. At every handoff, load the routed skill's source registry and propagate its version, freshness, and validation requirements.