Remove a Window Panel (kill it completely)

Deleting a window panel/overlay means removing it from every place the registration system spreads it across — then proving zero residue. A panel that "looks deleted" but leaves a stale OverlayId, a dangling opener, or a tile is a half-kill. No shims. No back-compat aliases. No fallback opener that forwards to the replacement. No commented-out block or // removed X tombstone. No dead panel name left in a comment.

Read the overlay-system skill first if you don't know how the overlay layer is wired. This skill is the reverse operation. Editing the WindowPanel component primitive itself (drag, resize, tray) → the window-panels skill, not this one.

The keystone strategy — pull the union member, let TypeScript hunt

OverlayId is keyof typeof OVERLAY_CATALOGUE — the keys of features/overlays/catalogue.ts — and the OverlayController's selectors are typed against it. So:

1. Delete the catalogue entry first — that removes the union member.
2. Run pnpm type-check. Every hard reference now fails to compile — the controller's isOpenById / dataById selectors, the opener's OVERLAY_ID as const, and any typed dispatch site. The compiler hands you the list.
3. Grep finds the soft references the compiler can't see — the tile, registry metadata, url-sync, comments, docs. Do both; neither alone is complete.

The removal checklist — every place a panel hides

Parameterize on <overlayId> (camelCase, e.g. agentContentSidebarWindow), <slug> (kebab, e.g. agent-content-sidebar-window), <Component> (e.g. AgentContentSidebarWindow), and the tile id / label / urlSync key.

#	Location	What to remove
1	features/overlays/catalogue.ts	The <overlayId>: { … } entry — its key IS the OverlayId union member. Do this first.
2	features/window-panels/windows/**/<Component>.tsx	The component file — git rm.
3	features/overlays/openers/<overlayId>.tsx	The opener file — git rm. No forwarding shim.
4	features/window-panels/registry/windowRegistryMetadata.ts	The whole entry (slug + overlayId + label + defaultData + any deprecated: block).
5	features/window-panels/tools-grid/toolsGridTiles.ts	The { id: "tile.<…>", overlayId: "<overlayId>" } tile.
6	features/overlays/OverlayController.tsx	Four sub-sites: the const <Component> = lazyOverlay(() => import(...)), the isOpenById selector entry, the dataById selector entry, and the gated JSX render block.
7	features/window-panels/url-sync/initUrlHydration.ts	Any registerPanelHydrator("<urlSyncKey>", …) for this panel.
8	features/window-panels/windows/<feature>/callbacks.ts	Only if it was a callback-aware opener — delete its callback contract.
9	features/admin/** (FeatureAdminMap), FEATURE.md, README/docs	Any map row, table row, or prose naming the panel.

Not every panel touches all nine — a panel with no urlSync skips 7, a non-callback panel skips 8. Steps 1–6 are universal.

The rewire step — repoint every opener before you delete it

A panel is used by whatever opens it. Find and repoint each to the replacement before removing the dead one:

# Every way to open it:
grep -rn "useOpen<Component>\|<Component>Controller" --include="*.ts*" .   # opener hook + declarative wrapper
grep -rn 'openOverlay({ overlayId: "<overlayId>"' --include="*.ts*" .       # raw dispatch sites
grep -rn "panels=<urlSyncKey>" --include="*.ts*" .                          # ?panels= deep links in code/docs

The Tools-grid tile is itself a usage — decide per task: remove it (capability gone) or repoint its overlayId to the replacement (capability moved). Confirm the replacement actually covers the dead panel's capability — parity is the user's call, never a silent capability drop.

Do NOT delete shared infrastructure the panel happened to touch

The single biggest over-kill mistake. Before removing anything the dead component imported, owned, or was marked with, prove it's unused elsewhere (grep / Explore subagent):

• The deprecated: metadata mechanism (red ring + banner) is shared by many windows. Remove the panel's entry, never the field type in windowRegistryTypes.ts or the rendering in WindowPanel.tsx.
• Shared icons in toolsGridTiles.ts — the import stays if another tile uses it.
• Shared exports the component re-exported. A window may export const ALL_TABS / TabContent that siblings import. If you delete the owner of a shared export, you orphan its consumers — relocate the shared piece first. (Check export lines in the component before git rm.)
• A import type in OverlayController that the deleted block used may still serve a sibling block — leave it if grep shows another user.

Clean comments, don't just delete

Other files may name the dead panel in a comment ("the same composition the legacy X used"). Reword to keep the useful doc and drop the dead name — don't delete the whole comment, don't leave the dead name. The user's bar: not even a comment mentions it.

Verify — the kill isn't done until this passes

1. Re-grep every token, case-insensitive, across the repo (exclude node_modules, .next*, .claude/worktrees). Must be empty:

   grep -rni "<overlayId>\|<Component>\|<slug>\|<label>\|tile.<tile-id>\|<urlSyncKey>" \
     --include="*.ts" --include="*.tsx" --include="*.md" . | grep -v node_modules
   

2. Deleted files gone; no import of the deleted opener/component paths survives.
3. pnpm type-check clean for every touched file (every controller selector, opener, and dispatch site is typed against keyof typeof OVERLAY_CATALOGUE, so a missed reference cannot compile — that is the safety net).
4. pnpm check:doctrine passes.
5. Spawn an independent Explore subagent to re-verify from scratch — hand it the checklist above and the token list. The user expects this as the standard final gate, not optional.
6. Inspect git status — commit only the panel's files. If unrelated files are dirty (concurrent work), stage your paths explicitly; never fold them in.

Worked example

The kill of Agent Editor (Sidebar) (agentContentSidebarWindow → replaced by agentAdvancedEditorWindow) touched exactly steps 1–6 + the comment cleanup, had zero external opener callsites (only the tile opened it), and kept the deprecated: mechanism + FileStack icon (both used elsewhere). That's the canonical shape: small, total, no residue.