package/tree_index.json

Coordinate to item for every room, with the forest's header counts.

What it holds

One key per room. Under it, counts (threads_given, threads_with_codes, items, coded, bridge, removed, dropped, orphans, na_stretches, coverage_of_coded_items, threads_total_in_window) and index: thread id, then coordinate, then the item (item_id, parent_id, author, created_utc, dt_parent_sec, dt_thread_sec, state, code_ids, labels, sequence, coverage, meta).

Who writes it, and when

build_store.py at stage 00, merging each room's forest/tree_index.json from the coders' input.

Why it exists

build_store.py describes it as "coordinate -> item, per room, with the header counts". It supplies the created_utc that forest nodes lack, and its counts become the forest field and threads_total in rooms.jsonl. A1 recomputes the forest header totals over trees/ and compares them with the store's figures.

Where

package/tree_index.json.

Checked against: tools/build_store.py, stages/STAGE-A1-reading-room-notes.md, package/tree_index.json.