ticket: preflight memory root marker

.yoi/tickets/open/20260607-062902-memory-root-uses-yoi-memory-marker/item.md

@@ -6,9 +6,9 @@ status: open
 kind: task
 priority: P1
 labels: [memory, workspace, worktree, config]
-workflow_state: intake
+workflow_state: ready
 created_at: 2026-06-07T06:29:02Z
-updated_at: 2026-06-07T06:29:02Z
+updated_at: 2026-06-07T07:45:01Z
 assignee: null
 legacy_ticket: null
 ---

.yoi/tickets/open/20260607-062902-memory-root-uses-yoi-memory-marker/thread.md

@@ -4,4 +4,70 @@
 
 Created by LocalTicketBackend create.
 
+---
+
+<!-- event: plan author: hare at: 2026-06-07T07:44:53Z -->
+
+## Plan
+
+## Preflight / implementation intent
+
+Classification: implementation-ready after `narrow-yoi-worktree-sparse-exclusions` landed.
+
+Intent:
+- Keep `.yoi` as the Yoi project records/workspace marker.
+- Stop using `.yoi` alone as the memory root marker.
+- Resolve repo-local memory through an explicit `memory.workspace_root` or an ancestor `.yoi/memory` marker, so child worktrees can contain `.yoi/tickets`/`.yoi/workflow` without becoming independent memory roots.
+
+Current code map:
+- `crates/memory/src/workspace.rs`
+  - `WorkspaceLayout::resolve(cfg, default_root)` currently uses `cfg.workspace_root.unwrap_or(default_root)`.
+  - `memory_dir()` is `<root>/.yoi/memory`; `knowledge_dir()` and `workflow_dir()` are also rooted under `<root>/.yoi`.
+  - Tests currently assert fallback to default root.
+- `crates/pod/src/pod.rs`
+  - Memory extract/consolidation/tools/resident setup call `WorkspaceLayout::resolve(&memory_cfg, &self.pwd)`.
+- `crates/yoi/src/memory_lint.rs`
+  - CLI lint works with explicit workspace path and may need to keep explicit workspace behavior.
+- `manifest::MemoryConfig` currently uses `Option<MemoryConfig>` presence as enablement and `workspace_root: Option<PathBuf>` as the explicit root. There is not yet a separate `enabled = false` field.
+
+Implementation direction:
+- Add a small resolver in `memory::WorkspaceLayout` or nearby that:
+  - honors explicit `memory.workspace_root` exactly as today;
+  - when no explicit root exists, walks ancestors from the default root and selects the nearest ancestor that contains `.yoi/memory`;
+  - does not select a directory merely because it contains `.yoi`;
+  - if no ancestor `.yoi/memory` exists, uses an explicit, documented fallback that does not silently interpret `.yoi` alone as the memory root. Prefer fail/no-marker behavior for automatic memory operations over creating child-worktree memory; if a lazy-create path is needed, keep it tied to explicit configuration rather than implicit `.yoi` presence.
+- Preserve `.yoi/knowledge`/`.yoi/workflow` project-record lookup semantics as much as possible; be explicit if moving memory root also changes knowledge/workflow layout root in a way that needs follow-up.
+- Do not implement user-data overlay fallback unless it is already supported and clearly smaller.
+- If adding a manifest `enabled` field would be broad, do not do it in this slice; document that current explicit disable is represented by absence of `[memory]` and keep the ticket focused on `.yoi/memory` marker resolution.
+
+Tests to add/update:
+- Explicit `workspace_root` still wins.
+- No explicit root + ancestor `.yoi/memory` selects that ancestor.
+- Child worktree containing `.yoi/tickets`/`.yoi/workflow` but no `.yoi/memory` does not select the child as memory root.
+- `.yoi` alone does not select a memory root.
+- Existing explicit workspace/lint behavior remains sensible.
+
+Validation:
+- Run `cargo test -p memory workspace --lib` or equivalent focused memory tests.
+- Run relevant `cargo test -p pod memory --lib` if Pod memory setup tests are affected.
+- Run `cargo test -p yoi memory --lib` if memory lint behavior changes.
+- Run `cargo fmt --check`, `git diff --check`, and `target/debug/yoi ticket doctor`.
+
+---
+
+<!-- event: intake_summary author: INSOMNIA at: 2026-06-07T07:45:01Z -->
+
+## Intake summary
+
+Implementation-ready after narrowed worktree sparse exclusions: keep `.yoi` as project records marker, resolve repo-local memory from explicit `memory.workspace_root` or nearest ancestor `.yoi/memory`, and ensure `.yoi` alone does not make child worktrees independent memory roots.
+
+---
+
+<!-- event: state_changed author: INSOMNIA at: 2026-06-07T07:45:01Z from: intake to: ready reason: intake_ready field: workflow_state -->
+
+## State changed
+
+Ticket intake complete; workflow_state intake -> ready.
+
+
 ---