Tiny World Mode Safety

Mode safety

• Boot always ends on the Select tool: bootApp calls selectTool(DEFAULT_TOOL) after loadState(), so a restored world's saved toolId never leaves a fresh session "armed" for building.
• Build/Play mode is separate from Showcase. #build-play-mode toggles body.tw-play-mode, persists tinyworld:build-play-mode.v1, and exposes window.__tinyworldIsPlayMode() / window.__tinyworldMode. In PLAY mode, build panels and edit radials are hidden, selection/sub-edit state is cleared, and mutation paths should be gated through the same edit checks that call mpEditAllowed().
• First load goes through #welcome-modal: the rounded .launch-modal shows assets/twlogo.png with Tinyverse, Battleworlds, Build, and Play buttons, includes the compact "Created by Jason Kneen" footer with @jasonkneen and @tinyworldsapp links, and hides app chrome via body.welcome-launch-open. Build/Play call window.__tinyworldMode; Tinyverse waits for window.__tinyworldWorlds.open() (or the tinyworld:worlds-ready signal) and opens the Worlds frontend rather than silently falling back to Build. Battleworlds calls window.__tinyworldBattleworlds.open() when present and otherwise falls back to Play. Do not bring back the old farm/vehicle welcome picker for this path, and keep publish.sh copying the assets/ directory into dist/assets/.
• Showcase mode keeps only a simple top-right circular #showcase-exit X button visible. Do not turn it back into a wide "Exit Showcase Esc" text pill; keep aria-keyshortcuts="Escape" and the existing Escape handler that calls setShowcaseActive(false).
• #mode-indicator (HUD chip, updated in updateModeIndicator in 19-tools-toolbar.js) names the current mode and colours itself: calm mode-select, amber mode-build, red mode-erase. Keep it pointer-events:none.
• Esc disarms any build/paint/erase tool back to Select (handler in 20-input-place-erase.js, skipped in first-person walk mode).
• The View modes popup has five modes: top-down, isometric, perspective, third-person walk (tp), and first-person walk (fp). Both walk modes are driven by the same fp controller in 20-input-place-erase.js; tp shows a chase camera behind the voxel avatar, while fp uses the avatar rig's getEyeWorldPosition() and hides the head via setFirstPerson(true). Keep tp in camera-mode schema/import allowlists when touching saved camera validation.
• Both walk modes are home-builder only. The fp avatar is added to the shared worldGroup, so it must never coexist with a Tinyverse room's own networked avatar or the player sees two copies of themselves. setCameraMode redirects fp/tp to perspective while window.__tinyworldInWorldRoom is set, and 47-worlds-room.js enterRoom calls window.__tinyworldExitWalkMode (exposed from 20-input-place-erase.js) to dispose any active walk avatar before spawning the room avatar. The room's own first-person is the surface roam zoom-in (v key, _sr* in 47), not the builder fp controller.

Gotcha

npm test (tools/check.js / smoke-static.js) reconstructs the split app from tiny-world-builder.html plus engine/**/*.js. Update those static guards when changing boot mode, launcher chrome, or mode persistence.

Bottom toolbar vs floating block palette

• The grouped bottom .toolbar is the default. The "Show groups" checkbox in Settings → App (#toolbar-show-groups, persisted as tinyworld:showGroups, default on) switches modes. When off, body.hide-groups hides only the bottom toolbar's block tools/group buttons and a floating, resizable, draggable #tool-palette shows every placeable block (select + all TOOL_GROUPS tools with house variants expanded + erase). The bottom toolbar itself must stay visible for utility controls such as Build/Play, Home, Shield, View modes, Time/weather, Sound, Layers, Settings, and Account.
• The palette is a self-contained module: engine/world/35-tool-palette.js. Blocks are built with buildToolButton(t, { flyout: true }), so they keep their colors and are highlighted by the same updateToolActiveStates() loop.
• Small screens force grouped mode. showGroupsEnabled() returns true on <=700px regardless of the stored pref (isSmallScreenForGroups()), the checkbox is disabled there, and a resize listener re-applies across the breakpoint. The floating palette is unusable on phones, so never let it open there. The phone toolbar is also compacted to icon-only (labels/chevrons hidden, smaller buttons) in the @media (max-width: 700px) block. The grid uses fixed 64px square cells (repeat(auto-fill, 64px)), so resizing the panel reflows blocks to the nearest square. buildToolbar() calls rebuildToolPaletteIfActive() so toolbar rebuilds refresh an open palette.
• The group popout flyout (.flyout.tool-menu) lays its icons out as a 2-row grid block (gridTemplateColumns: repeat(ceil(n/2), auto) set in renderToolGroupFlyout).
• The old vertical .controls rail is no longer visible. Keep its element IDs in the DOM as stable wiring targets, but put everyday chrome in the bottom toolbar: Build/Play, Home, Shield, View modes, Time/weather, Settings, and Account. Import/export must remain owner-gated and should not be added to the normal user toolbar.
• The old #mode-indicator HUD chip has been removed from the DOM; updateModeIndicator() still runs but no-ops on the missing element.
• In Tinyverse multiplayer HUD chrome, account sign-out is the only place that should use the door-arrow leave icon. The in-world exit that returns to the world picker uses tw-hud-back-worlds, the reply glyph, and worlds.backToWorlds so it is not confused with logging out.