diff --git a/docs/BACKLOG.md b/docs/BACKLOG.md
index ffd0ac1298..457ff244ad 100644
--- a/docs/BACKLOG.md
+++ b/docs/BACKLOG.md
@@ -318,6 +318,7 @@ are closed (status: closed in frontmatter)._
 - [ ] **[B-0520](backlog/P1/B-0520-new-surface-audit-alignment-check.md)** Mechanize new-surface audit for alignment-clause consistency
 - [ ] **[B-0522](backlog/P1/B-0522-pre-substrate-kenji-era-git-branches-inventory.md)** Pre-substrate Kenji-era git branches and worktrees inventory
 - [ ] **[B-0523](backlog/P1/B-0523-kenji-era-research-docs-cross-reference-audit.md)** Kenji-era research docs cross-reference audit (peeled from B-0139)
+- [ ] **[B-0526](backlog/P1/B-0526-branch-worktree-content-inventory.md)** Branch/worktree content inventory — Pre-substrate Kenji-era
 
 ## P2 — research-grade
 
diff --git a/docs/backlog/P1/B-0139-pre-substrate-kenji-era-otto-work-inventory-aaron-2026-05-01.md b/docs/backlog/P1/B-0139-pre-substrate-kenji-era-otto-work-inventory-aaron-2026-05-01.md
index f3db655678..9040a2d74a 100644
--- a/docs/backlog/P1/B-0139-pre-substrate-kenji-era-otto-work-inventory-aaron-2026-05-01.md
+++ b/docs/backlog/P1/B-0139-pre-substrate-kenji-era-otto-work-inventory-aaron-2026-05-01.md
@@ -8,7 +8,7 @@ last_updated: 2026-05-14
 depends_on: []
 type: friction-reducer
 decomposition: decomposed
-children: [B-0522, B-0523]
+children: [B-0522, B-0523, B-0526]
 ---
 
 # B-0139 — Pre-substrate Kenji-era inventory
@@ -73,7 +73,7 @@ Composes with task #321 (Recovery lane — branch/worktree/stash inventory + cla
 
 ## Status
 
-**In progress.** First slice landed: `tools/hygiene/audit-formal-artifacts.ts` — a TS script (Rule 0 compliant) that catalogs all formal verification artifacts (Lean4, TLA+, Z3, Alloy, formal tests) and cross-references each against docs/ for substrate-status. Finds 30 artifacts (4295 lines); 24 referenced in substrate, 6 unreferenced TLA+ specs (`AsyncStreamEnumerator.tla`, `BftConsensus.tla`, `ChaosEnvDeterminism.tla`, `ConsistentHashRebalance.tla`, `FeatureFlagsResolution.tla`, `InfoTheoreticSharder.tla`). Remaining slices: F# src/Core/ artifact inventory, docs/research/ cross-reference audit, branch/worktree content inventory, MEMORY.md backfill.
+**In progress.** First slice landed: `tools/hygiene/audit-formal-artifacts.ts` — a TS script (Rule 0 compliant) that catalogs all formal verification artifacts (Lean4, TLA+, Z3, Alloy, formal tests) and cross-references each against docs/ for substrate-status. Finds 30 artifacts (4295 lines); 24 referenced in substrate, 6 unreferenced TLA+ specs (`AsyncStreamEnumerator.tla`, `BftConsensus.tla`, `ChaosEnvDeterminism.tla`, `ConsistentHashRebalance.tla`, `FeatureFlagsResolution.tla`, `InfoTheoreticSharder.tla`). Remaining slices: F# src/Core/ artifact inventory, docs/research/ cross-reference audit, MEMORY.md backfill. Branch/worktree content inventory peeled off to B-0526.
 
 ## Verify-before-deferring note
 
diff --git a/docs/backlog/P1/B-0526-branch-worktree-content-inventory.md b/docs/backlog/P1/B-0526-branch-worktree-content-inventory.md
new file mode 100644
index 0000000000..37307af9f6
--- /dev/null
+++ b/docs/backlog/P1/B-0526-branch-worktree-content-inventory.md
@@ -0,0 +1,38 @@
+---
+id: B-0526
+priority: P1
+status: open
+title: Branch/worktree content inventory — Pre-substrate Kenji-era
+created: 2026-05-14
+last_updated: 2026-05-14
+depends_on: []
+parent: B-0139
+type: friction-reducer
+decomposition: atomic
+---
+
+# B-0526 — Branch/worktree content inventory
+
+**Priority:** P1 (lineage-continuity-substrate purpose).
+**Filed:** 2026-05-14.
+**Filed by:** Lior (decomposition of B-0139).
+**Effort:** M (archaeology of old branches).
+
+## What
+
+Inventory pre-substrate / Kenji-era past-recovery git branches and worktrees. This is an atomic slice decomposed from B-0139.
+
+Scope includes:
+
+1. **Past-recovery git branches** that haven't been triaged or merged.
+2. **Worktrees** still on disk that aren't referenced from substrate.
+3. **Branch / PR metadata** for closed-but-substantive PRs from Kenji-era.
+
+## Acceptance criteria
+
+1. **Branch/worktree inventory** of past-recovery state, with classification per item: integrated-into-main / abandoned / re-do-needed / preserve-in-substrate / discard-with-rationale.
+
+## Composes with
+
+- **B-0139** (Parent blob row).
+- **#321** (Recovery lane — branch/worktree/stash inventory).