Evidence Card — First-Hand Upstream Vespa Codebase & Anchor Audit

Direct workspace verification of upstream directories and anchor files in “ supporting the core Zettelkasten notes, bridges, and invariant cards.

Verified Upstream Anchors

1. Proton & LID Space (vespa/searchcore, vespa/searchlib, vespa/vespalib):
   • vespa/searchcore/src/vespa/searchcore/proton/ (1,210 files, ~131k LOC)
   • vespa/searchlib/src/vespa/searchlib/attribute/ & vespa/searchlib/src/vespa/searchlib/tensor/ (2,492 files, ~305k LOC)
   • Grounds proton-lid-space-and-attribute-vectors, hnsw-single-pass-prefiltering, and inv-lid-monotonic-generation-guard.
2. Stateless Container & Searcher Chain (vespa/container-search, vespa/jdisc_core):
   • vespa/container-search/src/main/java/com/yahoo/search/searchchain/Execution.java (1,202 files, ~171k LOC in container-search)
   • Grounds jdisc-stateless-searcher-chain-execution and inv-jdisc-searcher-stateless-fill-discipline.
3. Cross-Language Tensor & Config Bridges (vespa/vespajlib, vespa/eval, vespa/config-model):
   • vespa/vespajlib/src/main/java/com/yahoo/tensor/serialization/TypedBinaryFormat.java
   • vespa/eval/src/vespa/eval/eval/tensor_function.h
   • vespa/config-model/src/main/java/com/yahoo/vespa/model/content/engines/ProtonEngine.java
   • Grounds vespa-tensor-type-system-and-algebra, bridge-java-cpp-tensor-serialization, and bridge-config-model-to-proton-subscription.