diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index 7548b4c..3caa54b 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -117,6 +117,8 @@ harb/
 │   ├── src/
 │   │   ├── components/  # ProtocolStatsCard, etc.
 │   │   └── views/       # LoginView, StakeView, etc.
+├── kraiken-lib/       # Shared TypeScript helpers (bigint math, ABIs, encoding) for frontend and indexer
+│   └── src/           # abis, format, ids, position, snatch, staking, subgraph, taxRates, version
 ├── containers/        # Docker configs, entrypoints
 ├── docs/              # This file, PRODUCT-TRUTH.md
 └── .woodpecker/       # CI pipeline configs