Merge pull request #225 from manecke/feature/granularity-for-mandate-related-attestations

adr: add decision record on atomic granularity for mandate-related at…

Author: Saramandus

adr/Atomic-Granularity-for-Mandate-Related-Attestations.md

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+# Atomic Granularity for Mandate-Related Attestations
+
+**Authors:**
+
+- Consortium Architecture Working Group AMS Track 4
+
+- Boris Lingl, boris.lingl@datev.de
+- Alexander Manecke, a.manecke@telekom.de
+- Ignacio Ripoll, ignacio.ripoll@corpme.es
+- Iris Speiser, iris.speiser@datev.de
+- Marlene Urbschat, marlene.urbschat@datev.de
+
+## Context
+
+Individuals may hold multiple powers, mandates, or authorizations on behalf of an organization.
+
+The consortium needed to determine whether mandate-related attestations should contain multiple faculties or be limited to a single authorization scope.
+
+The core trade-off is between expressiveness and implementation simplicity.
+
+## Decision
+
+Mandate-related attestations shall be atomic.
+
+Each attestation shall contain exactly one faculty or one service authorization.
+
+Multiple powers shall be represented by multiple attestations rather than by composite authorization structures.
+
+## Consequences
+
+### What becomes easier?
+
+- Simpler issuance and validation processes.
+- Clear and unambiguous authorization semantics.
+- Improved interoperability across participants.
+- Easier lifecycle management of individual permissions.
+
+### What becomes more difficult?
+
+- Multiple attestations may be required for a single representative.
+- Presentation and management of large authorization sets may become more complex.
+- Real-world mandate structures may require aggregation mechanisms.
+
+### How do we address the risks introduced by this change?
+
+- Allow wallets and verifiers to present and process multiple attestations together.
+- Define guidance for bundling and presenting related attestations.
+- Reassess granularity requirements as additional use cases emerge.
+
+## Advice
+
+- 2026-06-11: Consortium Working Group: Prefer simple, composable attestations over complex multi-purpose credentials.
+- 2026-06-11: Technical Participants: Atomic credentials simplify interoperability and validation logic.