# ADR 0003: Stable Privacy Subset With Experimental Verification
## Status
Accepted
## Context
Cougr contains both defensible privacy primitives and faster-moving proof-verification helpers. Treating them as one maturity tier would overclaim guarantees.
## Decision
Cougr formally splits privacy into:
- `zk::stable` for commitments, commit-reveal, hidden-state codecs, and Merkle verification
- `zk::experimental` for advanced proof verification, circuits, channels, recursive layouts, and hazmat helpers
## Consequences
- privacy claims can stay narrow and defendable
- advanced ZK work can continue without blocking the stable subset
- compatibility promises can be scoped precisely by namespace