This standalone development app exposes Labello's shared UI through eframe's inspection protocol. It is intentionally outside the main Cargo workspace and uses deterministic demo state by default. It is an inspection harness, not a supported native client. Presets prove shared rendering in synthetic states; live mode exercises the supported native API path. Chromium is still required for production WASM and browser behavior.

Install the MCP server compatible with this inspector's egui 0.35 dependency:

cargo install egui_mcp --version 0.1.0 --locked

For Codex, register the installed binary with an absolute path:

codex mcp add egui -- "$(command -v egui-mcp)"

Open a new Codex session after registration so it loads the MCP tools. OpenCode already has the egui server in the repository's opencode.json; restart OpenCode after changing that configuration. The agent host starts the configured MCP bridge when it loads the tools; launch the inspector app separately, then call attach.

For a machine with a working graphical display, run from the repository or assigned worktree root:

EGUI_INSPECTION=127.0.0.1:5719 cargo run --locked \
  --manifest-path apps/egui-mcp-inspector/Cargo.toml -- --preset setup

Keep inspection bound to loopback. It exposes app control without authentication. attach defaults to 127.0.0.1:5719; use an explicit port for parallel instances.

Xvfb provides an in-memory X11 display; Mesa software rendering supplies the OpenGL renderer. No monitor or physical GPU is required for this native smoke test. Check for Xvfb, xvfb-run, xauth, dbus-run-session, and the native eframe libraries before launching. Cargo build prerequisites are maintained in the verification reference.

On a Debian-family system, obtain Xvfb from the host distribution's packages. For a user-local installation, apt-get download xvfb downloads the package without root, and dpkg-deb -x <downloaded-deb> <installation-directory> extracts it. Check ldd <installation-directory>/usr/bin/Xvfb for missing dependencies. Extraction alone does not install its dependencies.

With Xvfb installed and on PATH, run this from the exact checkout root:

env -u WAYLAND_DISPLAY \
  LIBGL_ALWAYS_SOFTWARE=1 EGUI_INSPECTION=127.0.0.1:5721 \
  dbus-run-session -- xvfb-run -a -s '-screen 0 1600x1200x24 -nolisten tcp' \
  cargo run --locked --manifest-path apps/egui-mcp-inspector/Cargo.toml \
  -- --preset setup

xvfb-run -a chooses a free display. The screen dimensions are the virtual display capacity; use MCP resize to change the app window. Keep the app running in its own terminal/process session while sending MCP commands. Capture screenshots while the window is rendering; a minimized window can time out.

1. Record the worktree, git rev-parse HEAD, relevant uncommitted diff, preset or live scenario, and allocated inspection port. Build from that worktree with its tracked lockfile. Restart the app after code changes; a running inspector retains its old build.
2. Call attach with {"host":"127.0.0.1","port":5721} and verify status reports a connected Labello MCP Inspector on that port. Match the listener PID to the process you launched. The generic app label does not identify its checkout or revision. A listening socket alone is not a passed check.
3. Read query_tree before interacting. Use a node ID or an unambiguous role/text locator, then click, type_text, press_key, scroll, or drag. Use wait_for on the resulting state before asserting behavior; a successful input call alone does not prove the intended state appeared.
4. For a safe smoke test on the Setup preset, open Settings, wait for Keyboard shortcuts, dismiss with Escape, and verify that heading is absent. At compact widths first click Open navigation, then Settings. The wide app-bar button is named Open settings. Inspect actual names rather than assuming labels are identical across layouts.
5. Use resize and screenshot for the applicable viewport and scaling matrix. A useful startup check is 1440x1000 and 390x844. Inspect the returned PNG as well as the widget tree. Screenshot pixels_per_point controls output resolution; it does not emulate browser DPR, zoom, or platform text scaling.
6. Map issue acceptance criteria to deterministic tests, native inspection, live interactions, and required Chromium checks. Record commands, outcomes, dimensions/scale, artifact paths, and checks not performed. Apply the redaction contract to logs, tree dumps, and screenshots. Persist only evidence free of credentials, image bytes, annotation geometry, review comments, uploaded filenames, and import paths. The Setup preset is suitable for testing screenshot capture without work content. Keep evidence outside tracked/runtime dataset paths.
7. Call disconnect, then stop the app using its owning process session. Disconnection only closes the MCP attachment. Let xvfb-run clean up its display and verify the allocated inspection port is no longer listening. Stop only your own processes.

Allocate one inspection instance per active driver. A sequential issue track may reuse its worktree, but simultaneous implementation and independent review need separate app instances.

Each egui-mcp process stores one active attachment. Multiple clients can connect to an app, but they operate on the same UI state. Two agents using a shared MCP bridge can also change each other's attachment. Separate TCP ports alone therefore do not isolate shared tools.

Check whether the agent host gives subagents independent MCP processes. If it shares them, either use separate stdio clients per driver, configure distinct named MCP servers for the concurrent drivers before starting their sessions, or serialize inspector access. Do not assume inherited MCP tools are isolated. Disconnect and reattach to change apps only when you own that bridge.

Keep allocations and process ownership in the handoff. A port conflict is a failed launch, not permission to attach to or stop its occupant.

In live mode the current app initially targets http://127.0.0.1:8080. To use a dedicated server on another port, select its endpoint through Advanced connection > API URL > Reconnect before signing in or claiming work. There is no inspector CLI endpoint flag. Configure each disposable server using the server configuration contract, including LABELLO_CONFIG, LABELLO_BIND, and LABELLO_DATASETS_ROOT where appropriate.

The default is the annotation preset. Use -- --preset <name> with Cargo for another frozen state.

Available presets are dataset-gallery, dataset-inspection, annotation, overlapping-boxes, overlapping-boxes-unfiltered, prelabel-boxes, presence, presence-fallback, setup, about, build-mismatch, build-unavailable, build-update-failed, review, review-correction, admin, prelabels-disabled, prelabels-disabled-annotation, statistics, statistics-global, global-shortcuts, dialog-settings, dialog-transition, dialog-admin-discard, setup-failure, admin-failure, statistics-failure, streak-lit, assignment-failure, image-failure, import-source, import-preflight, import-ready, import-running, import-failure, import-success, import-multiple-descriptors, import-yolo-splits, export-selection, export-loading, export-ready, export-blocked, export-running, export-failure, export-success, export-request-failure, import-server-folder-picker, import-server-descriptor-picker, import-partial-categories, import-recovery-blocked, migration-object, migration-single-optional, migration-exclusion, migration-pass, migration-full-image, migration-review, migration-discovery, migration-discovery-review, migration-companion-annotation, migration-annotated-edit, and migration-guide-deleted. The migration-single-optional preset reproduces a pending imported guide with one optional center keypoint and no positioned draft input, without a server or dataset. The prelabel-boxes preset opens two synthetic pending bounding boxes for confirmation, deletion, and Undo/Redo inspection. Preset actions are intentionally local and deterministic; restart with another preset for a clean inspection context. The statistics and statistics-failure presets open an accessible, scrollable statistics modal above Setup; Escape or Close returns to that underlying view. The streak-lit preset shows a four-day labeling streak with today's goal met in both the leaderboard and the underlying application bar.

overlay-annotation, overlay-review, overlay-correction, and overlay-migration show visible, occluded, and not-present keypoints over synthetic white, black, and textured regions. Annotation includes an active skeleton draft and prelabel suggestions; correction includes a focused occluded keypoint. These fixtures exercise the shared production painter.

To connect the inspector to a running Labello server instead, use live mode:

EGUI_INSPECTION=127.0.0.1:5719 cargo run --locked \
  --manifest-path apps/egui-mcp-inspector/Cargo.toml -- --live

Live mode defaults to http://127.0.0.1:8080. When the loopback server enables developmentAuth.localAdminLogin, use Continue as local admin on the login page. The inspector retains that local session without exposing credentials in arguments, URLs, or UI fields.

Live mode uses real server state: opening work can claim an assignment, and UI actions can modify the selected dataset. Use a disposable development dataset for destructive testing and release or skip claimed work before exiting. Folder upload, snapshot download, OAuth sessions, and persistent native drafts remain browser-only or unsupported in the inspector.

Use the headless launch recipe with --live when no graphical display is available. Preset or native live-mode evidence must be accompanied by the Chromium checks required by the verification contract.

The build-update-failed preset shows the browser update failure and retry control in About without navigating.

The build-information presets use synthetic release identities. about shows matching identities, build-unavailable shows the local unavailable state, and build-mismatch adds the warning to an annotation workspace. Native inspection proves shared layout and named semantics. Actual artifact binding, visible-tab refresh and browser clipboard success/rejection require Chromium. Without a clipboard adapter, the native About screen offers selectable manual-copy text and reports that automatic copying is unavailable.

The presence presets show the current user and a local-ID fallback in the shared work header. presence seeds the shared avatar cache with a synthetic image; presence-fallback seeds an unavailable photo. Both are deterministic and make no avatar requests. Hover and activation expose the GitHub handle and dataset names. Photos and initials are static. Browser avatar networking requires Chromium.

The workflow-reasons preset shows a synthetic rejection comment and earlier approval feedback independently of workflow-change acknowledgment. Use it to inspect event headings, message-first ordering, scrolling, dismissal and the short-viewport feedback window; it does not prove history loading or browser behavior.

The review-initial-load, review-next-image, and migration-next-image presets freeze an image request with no active assignment. Initial review leaves the context and action bars blank; next-image presets retain the preceding view's canvas, inspector context and disabled bar presentation. They exercise the shared presentation owner, not live networking. Use Chromium with delayed responses for the actual request transition.

The workflow-availability preset shows all ten server restriction icons, including a selected unavailable workflow, without image or annotation content. Use it to inspect disabled tooltips, marker alignment, and the workflow drawer.

The workflow-boost preset shows an unselected boosted workflow beneath another class. Its amber rim and glow use the production renderer; the native preset keeps the default static reduced-motion presentation. Chromium exercises the activation and hover shimmer with the browser motion preference.

The workflow-classes preset models HSLVision's seven classes with box workflows and five split migration workflows, using synthetic data. At 1920 × 1080 the full picker fits without scrolling; shorter viewports exercise drawer scrolling.

The navigation-failure preset shows a refused Previous action above the retained Overview review workspace. Its dismissible alert uses the same shared renderer as workflow-change notices. It does not exercise server history eligibility.

The workflow-change preset shows the nonmodal automatic workflow-change notice. Check that it remains visible after item loading, wraps within the viewport and can be dismissed while work remains available. The annotation-objects, annotation-overview, review-objects and review-overview presets include typed queue contexts for the split selector and item-scoped editor. They do not prove server claims, history or draft handoff; use disposable live data for those checks.

statistics-global renders the aggregate of two synthetic dataset projections. global-shortcuts renders the explicit legacy preference selection above Setup. Both use the shared production renderers without account or image data.

The migration-review-object and migration-review-excluded presets use Objects review assignments without legacy review contexts. They show read-only source-box context and the bottom-bar skeleton creation action with the Inspector collapsed. They prove shared rendering; use live browser checks for correction submission.