ADR: Compiled-artifact cache

Status

Proposed (2026-07-14) — gated on benchmark evidence; not implemented.

Context

Contract compilation is stateless today. Before adding cache ports or mutable core state, the project needs reproducible baselines for compile/render and document inspect/render latency, output size, and hostile-input rejection cost.

Decision

1. No cache in the first safe document-template wave. Unit 3 benchmark harness (tools/templiqx-bench) records machine-readable baselines locally.
2. A cache is considered only when:
   • benchmarks identify a material, repeatable bottleneck;
   • keys include package/contract/input/context/capability/compiler fingerprints relevant to the cached artifact;
   • storage is host/store-backed outside templiqx-core and default local composition.
3. Package identity and receipts must remain valid without cache hits.

Consequences

• Hosts may implement their own caches behind typed ports without changing portable contracts.
• Performance claims require cited benchmark reports, not assumed speedups.

Alternatives considered

• In-core memoization. Rejected — breaks determinism proofs and boundary rules for default composition.
• Implicit HTTP cache headers only. Rejected — insufficient for compile artifacts and document render receipts.