ADR-011 Relaxed Atomicity for Diagnostic Lookup

Status: Accepted Date: 2025-10 Tags: lookup, atomicity, diagnostics

Problem

interface.md required atomic lookup (MUST use atomic script/transaction), but Firestore used non-atomic indexed queries. This created spec contradiction despite lookup being explicitly diagnostic-only—NOT a correctness guard.

Decision

Relax atomicity requirement to match diagnostic nature:

• SHOULD be atomic for multi-key stores (Redis via Lua script)
• MAY be non-atomic for indexed stores (Firestore single indexed query)
• Strong warning: lookup is for diagnostics/UI/monitoring ONLY—never gate mutations on it

Alternatives (brief)

• Require atomicity everywhere — unnecessary overhead for Firestore
• Remove lookup entirely — loses valuable diagnostic capability

Impact

• Positive: Removes spec contradiction, simplifies Firestore, preserves Redis atomicity
• Negative/Risks: None—no implementation changes needed

Links

• Code/Docs: docs/specs/interface.md (Lookup Operation), backend specs
• Related ADRs: ADR-003 (ownership verification for mutations)