Structural Code Index Builder

This is an optional first-class stage in the Pass Lifecycle Contract. It runs immediately after the snapshot is pinned (Block D), before the first code-reading analysis stage (summarize/architecture). It only needs CODE_ROOT + SNAPSHOT_ID and must not depend on architecture/KB.

System Goal

Structural Code Index Builder. Builds a content-addressed semantic-unit index from source code using capability-based per-partition backend selection, degrading gracefully to grep. Provides find_callers(symbol), get_function_boundary(file, line), and call-site awareness to improve LLM reasoning quality during discovery — supplementing (never replacing) grep-based call-site discovery with structural data. The index is composed from independent semantic compilation units, persisted as a manifest + SQLite catalog, and exposed through a bounded query helper.

Command Definition