01 — Layer Definition Canon — Readback

Readback status: PASS (no repair needed)

The GPT-uploaded canon knowledge/dev/design/registries-pivot-os-agency/layer-definition-dynamic-drilldown-canon-2026-06-03.md is searchable and fully readable via MCP this session:

• search_knowledge("Layer là cấp danh sách sinh ra từ node cha khi count > 1") → top hit, score 1.41.
• batch_read(full=true) → returned all 1,732 chars, truncated=false, revision 1.

The prior tool-safety block on immediate read-back was transient; the document persisted correctly. No reupload/repair was required. A shorter checkpoint copy was therefore NOT created (would duplicate canon).

The canon (verbatim summary)

Layer là một cấp danh sách sinh ra từ một node cha khi node cha có count > 1. Layer không phải cấp cố định 1/2/3/4/5 — nó là kết quả của một phép phân nhóm tiếp theo do PG/pivot quyết định. Nếu node count > 1 và còn grouping_dimension hợp lệ → có layer con. Nếu count = 1 hoặc hết grouping_dimension → đi vào final substrate (DB/table/registry/birth/IU/KG/DOT/events/governance/audit của chính object đó).

Backend decides has_children, child_layer_kind, next_pivot_code, drilldown_query_ref, final_substrate_ref. Missing grouping/parent ⇒ PIVOT_MISSING, never silent hardcode fallback.

Reconciliation with older RP docs (conflict scan)

Source	Says	Conflict?	Resolution
04-dynamic-drilldown-layer-model.md	count>1 ⇒ child layer, variable depth	none	identical principle
00-master-design-v0.1.md §2	Điều 26 fixed 5-Layer (L1..L5)	apparent	L1/2/3 are UX labels; the 5-layer is a human-facing generalization of the recursive rule, NOT a backend depth cap
Điều 26 law	5-Layer model	apparent	same resolution

Final canon note (authoritative)

• Human-facing UI labels (Layer 1/2/3) MAY be fixed for UX clarity.
• Backend layer generation is dynamic + recursive, driven by pivot_definitions.parent_code + grouping dimension, never by hardcoded depth or naming convention.
• The two senses of count > 1 must not be conflated: here it is a UI navigation trigger (expose a child layer); the governance sense (candidacy, M-DEF-10) is separate and untouched by this surface.

Citable as canon in future Agent/GPT work.