0004-service-capabilities-and-aggregations.md•842 B
# ADR 0004: Service Capabilities (Root, Conformance, Queryables) and Aggregations
Status: Accepted
Date: 2025-09-18
## Context
- Clients benefit from discovering service capabilities and queryable fields.
- Some APIs support Aggregations extension for counts/histograms.
## Decision
- Add tools:
- get_root: id/title/description/links/conformance
- get_conformance: list conformance classes; optional check param
- get_queryables(collection_id optional): return queryable fields
- get_aggregations: run a search and return aggregations (if supported)
- Fail gracefully when endpoints/extensions are not available.
## Consequences
- Better adaptability across catalogs and richer UX.
- Requires detection of conformance and conditional behavior.
## Alternatives considered
- Hard-code assumptions per catalog (rejected; brittle).