Dev URL parameters

The query parameters a game's page reads. Add them to the page's URL in the browser: on the dev server (npm run dev from the root of the engine repository, or from a created project's folder), the address is http://localhost:5173/ unless Vite says otherwise. Some are development tools, read only by a development page; the others work in every build, the production one included.

Which builds read them

• ?dev, ?edit=<room> and &at=<checkpoint> turn on the dev tools only on the dev server, in a Studio demo build (studio.demo-mode) and in a hosted Studio's previews of a revision (src/main.ts). Without them the player's game is the same in every build; a production build ignores them.
• Every other parameter below is read by the engine in every build.

URL	Effect	Build
/	The normal game: title screen, New Game / Continue.	every
/?dev	Starts on the first checkpoint, with the debug layer and the DEV panel.	development
/?dev&at=<checkpoint>	Starts on this checkpoint (one of the game's checkpoints).	development
/?edit=<room>	The room's placement editor.	development
/?edit=<room>&at=<checkpoint>	The same, in that checkpoint's state (to place a prop in a given state).	development
?lang=<code>	The language to play in.	every
?renderer=canvas|dom	Forces a painter for every room.	every
?music=mix|stems	Forces the single mix or the stems.	every
?fps	A frame counter in a corner.	every
?seed=, ?daily=, ?world=	Opens a Remix world.	every
?reality=sim	A simulated world link.	every
?speedrunTool=<port>	Posts the run's events to a local speedrun tool.	every
?token=<token>	The LAN Studio's token.	dev server in LAN mode

?dev: the layer and the DEV panel

/?dev starts the game on its first checkpoint with the engine's trace on, the debug layer and the DEV panel (src/engine/dev/).

• Layer, drawn over the scene:
  • clickable zones in blue, props in purple, characters in green;
  • the walkable zone in green, holes (furniture) in red;
  • depth-scale lines in orange, entry points in pink;
  • approach points: filled if set in the layout, hollow if computed.
• Show or hide the layer: the D key, or the DEV button in the bottom left (on a phone).
• Panel:
  • the current room and the "busy" state (a script is running);
  • Checkpoints: load a ready state, or start a New Game;
  • Rooms: go to any room, without playing its arrival script;
  • Bag: check or uncheck an item;
  • Flags: edit existing flags, or set a flag name and value (true, false, a number or text);
  • Map: unlock a place, or Unlock all;
  • World: the room of each moving character (change it to moveActor them);
  • Scripts: the position of each script in scope (next command / length, done, stopped), with a stop or restart button;
  • Journal: the last ten entries of the engine's journal (what answered, events, script steps, moves, switches; the Studio's Play tab shows it whole), and Export session: the inputs since the game started, with the session's semantic journal, for npm run replay;
  • Semantic journal (4.1.11): the last twelve events the core numbered in this session (room entered, item acquired or lost, flag changed, ending, load, save), refreshed with the panel;
  • Edit this room: opens the editor on the room shown.

&at=<checkpoint>

With ?dev or ?edit=, starts on that checkpoint, an id of the game's checkpoints, instead of the first one.

?edit=<room>: the placement editor

/?edit=<room> opens the room's placement editor. On start it loads the first checkpoint located in that room; if there is none, it starts from a fresh state, without playing an arrival script. All coordinates are logical (640 × 400). The gestures and the editor's panel are described in studio.placement.

• Saving writes games/<GAME>/layout/<room>.json in the engine repository (game/layout/<room>.json in a created project), coordinates rounded to the unit, through the Studio's API (PUT /__studio/api/room/<room>/layout, one guarded operation of the game's journal: studio.api); the page then reloads with the saved file. Where there is no Studio API (a Studio demo build, a static host), the layout joins the demo's edits in this browser. A refusal of the Studio is shown with its reason.
• In the Studio (/__studio/), the editor runs in an iframe and talks to the Studio's page with postMessage, to the Studio's origin only (the page's own origin, or on a hosted Studio the origin its web-scumm-studio-origin meta tag names). It sends { source: 'web-scumm-editor', room, type } messages: ready (with missing, the entities that have no place yet), select (key such as prop:lamp, hs:door, actor:grandma, plus kind and id for those three), dirty (unsaved changes) and saved (ok, error; on a hosted Studio also the layout and the request's nonce, the Studio writing it). It accepts { source: 'web-scumm-studio', type } messages: select (kind, id), create (gives a place to an entity the room declares but the layout lacks, optionally at at) and save (optionally with a nonce). In an iframe its panel starts folded.

?lang=<code>

The language to play in, when the game ships it: it comes before the player's saved choice and the browser's language (pickLanguage, engine.api). See play.languages.

?renderer=canvas|dom

Forces one painter for every room: the visual parity check, the Studio's comparison. Any other value is ignored and each room keeps its own renderer.

?music=mix|stems

Forces the single mix or the director's stems (tests, the Studio); otherwise the device decides (create.music).

?fps

A frame counter in a corner (3.8): the frame rate now and the lowest second seen, for the real-phone pass.

?seed=, ?daily=, ?world=: a Remix world

For a game that declares remix (4.1.15): ?world=<frozen world> (its hash checked when it is applied), ?seed=WS-… (the remix mode) or ?daily=<signed day token> names the world the page plays. The autosave's world comes first (Continue never disappears); a link to another world than the saved game's is asked on the title screen, never adopted silently. See create.remix.

?reality=sim

For a game that declares reality: the world link is simulated, as it always is with the dev tools on, and no Bridge is contacted (bridge.signals-manifest).

?speedrunTool=<port>

The page posts its run's events (category, split ids and names, times; nothing else: no save, no player id, no token) to a local tool on that port of this machine: the OBS overlay or the LiveSplit autosplitter (4.1.14, D23). The port is 2 to 5 digits; the tool accepts them only from its allowed origin. See play.speedrun.

?token=<token>

On the dev server in LAN mode (npm run dev:lan, npm run studio:lan), the one-session capability token the server prints in its URL. Given once, it is kept in an HttpOnly, SameSite=Strict cookie; a request without it (and without the x-web-scumm-token header) is refused with 401. See studio.security and create.lan-testing.