Artboards: Fit to Artwork Bounds fits each selected artboard to the art on it

Fit to Artwork Bounds resized the active artboard to the bounds of all
the art in the document, wherever that art was. With art on two
artboards, fitting one of them stretched it over both.

artboard.fitToArt now takes `indices` and fits each artboard to the
art on it, in one undo step. An object counts for every artboard its
drawn bounds overlap, and the artboard is fitted to all of its bounds,
also where it reaches past the artboard's edge. Art flush with an edge
from outside does not count. An artboard with no art on it keeps its
size and place, and the command fails with "no artwork" when none of
its artboards has art. Object › Artboards and the Artboards panel menu
pass the selected artboards (the Artboard tool's, else the active one),
and a recorded action leaves them out. Fit to Selected Art still
resizes the active artboard.

Docs: docs/mcp.md, docs/target-app-parity.md.

docs/mcp.md

@@ -1835,13 +1835,20 @@ Direct Selection or Group Selection tool inside an artboard makes that artboard
 tool, a Shift-click on an empty spot inside an artboard makes it active and keeps the selection. Choosing the Artboard
 tool (`tool.select {tool: "artboard"}`) starts it on the active artboard: its `active` option is that artboard's index.
 
-`artboard.fitToArt {index?}` (Object › Artboards › Fit to Artwork Bounds) and `artboard.fitToSelection {index?}`
-(Object › Artboards › Fit to Selected Art) resize artboard `index` (a 0-based index), or the first artboard when the
-call gives none. The desktop app adds its active artboard as `index` to the calls of these two commands that it runs
-without `index`, MCP's `run_command` calls in remote mode included. A batch passes its `artboard` on to each of their
-steps that names no `index`, as the step's `index`. When the document a step runs in has no artboard at that index,
-the step gets that document's last artboard. An action recorded in the Actions panel leaves `index` out of these
-steps, and they resize the artboard that is active when the action plays.
+`artboard.fitToArt {index? | indices?}` (Object › Artboards › Fit to Artwork Bounds) fits each artboard it names to
+the art on that artboard, in one undo step. The art is what an export draws, measured with its strokes and with the
+effects on paths, compound paths and symbol instances. An object counts for every artboard its bounds overlap, also
+when it reaches past the artboard's edge, and a group or a clipping layer counts whole. An artboard with no art on it
+keeps its size and place, and the call fails with `no artwork` when none of its artboards has art.
+`artboard.fitToSelection {index?}` (Object › Artboards › Fit to Selected Art) fits artboard `index` to the selected
+art. Both commands take 0-based indexes and resize the first artboard when the call names none. The desktop app adds
+the selected artboards (those the Artboard tool has selected, else the active one) as `indices` to the
+`artboard.fitToArt` calls it runs without `index` or `indices`. It adds its active artboard as `index` to the
+`artboard.fitToSelection` calls it runs without `index`. Both include MCP's `run_command` calls in remote mode. The
+Artboards panel menu's Fit to Artwork Bounds also passes the selected artboards. A batch passes its `artboard` on to
+each of their steps that names no `index`, as the step's `index`. When the document a step runs in has no artboard at
+that index, the step gets that document's last artboard. An action recorded in the Actions panel leaves `index` and
+`indices` out of these steps, and they resize the artboard that is active when the action plays.
 
 ```json
 {"name":"run_command","arguments":{"command":"object.align","params":{"horizontal":"left","to":"artboard","artboard":1}}}

docs/target-app-parity.md

@@ -511,7 +511,8 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   With Align to Artboard chosen, the Align panel's Distribute Objects and Distribute Spacing buttons use the active artboard (`object.distribute` and `object.distributeSpacing` with `to: "artboard"` and `artboard`). The first object's left or top edge goes to the artboard's left or top edge, and the last object's right or bottom edge goes to the artboard's right or bottom edge. Distribute Objects spaces the other objects evenly by its button's line, and two objects are enough. Distribute Spacing makes the gaps between the objects equal. With anchor points selected, the buttons space the points among themselves and do not use the artboard. When an action plays, its Distribute Objects and Distribute Spacing steps with Align to Artboard use the artboard that is active then.
   With a key object, the Align panel's Distribute Objects buttons use the Distribute Spacing value (`object.distribute {spacing}`): the key object, or the compound path or selected group that contains it, stays in place, and the objects' left edges, centers or right edges (top edges, centers or bottom edges) end up that far apart, outward from the key object's, in their order. With the field's default value of 0, a click puts every object on the key object's line (behavior reference: [Ask Mordy: Distributing Objects](http://rwillustrator.blogspot.com/2008/01/ask-mordy-distribute.html)).
   Choosing the Artboard tool (Shift+O, its toolbar button, Edit Artboards in Properties or Document Setup, or the Artboards panel menu's Artboard Options…) starts it on the active artboard: the canvas outlines that artboard, and Delete, Cut, Copy, the Transform panel and Artboard Options act on it.
-  Object › Artboards › Fit to Artwork Bounds and Fit to Selected Art resize the active artboard, as the Artboards panel menu's Fit to Artwork Bounds does (`artboard.fitToArt {index}`, `artboard.fitToSelection {index}`). They used to resize artboard 1 whichever artboard was active. When an action plays, its Fit to Artwork Bounds and Fit to Selected Art steps that name no artboard resize the artboard that is active then.
+  Object › Artboards › Fit to Selected Art resizes the active artboard (`artboard.fitToSelection {index}`). It used to resize artboard 1 whichever artboard was active. When an action plays, its Fit to Artwork Bounds and Fit to Selected Art steps that name no artboard resize the artboard that is active then.
+  Object › Artboards › Fit to Artwork Bounds and the Artboards panel menu's Fit to Artwork Bounds fit each selected artboard (those the Artboard tool has selected, else the active one) to the art on it, as the public [Use the artboard context menu](https://helpx.adobe.com/illustrator/desktop/create-manage-artboards/organize-manage-artboards/use-artboard-context-menu.html) page describes (`artboard.fitToArt {indices}`). An object partly on an artboard counts for each artboard it overlaps, and an artboard with no art on it keeps its size and place. They used to fit the active artboard to all the art in the document.
   The canvas draws the active artboard's edge in black, as the public [Select artboards](https://helpx.adobe.com/illustrator/desktop/create-manage-artboards/add-edit-artboards/select-artboards.html) page describes. It draws the other artboards' edges in gray. With several artboards selected by the Artboard tool, the canvas draws the black edge around the active one, which the tool shows with handles and its name. It used to draw artboard 1's edge in black whichever artboard was active.
   View › Rotate View turns the view to the status bar's preset angles (`view.rotate {angle}`, which takes any angle). View › Rotate View to Selection turns the view to the angle of the selected objects' bounding box, so the box is square to the window (`view.rotateToSelection`).
   When the view angle changes (a Rotate View drag, the status bar's angle menu, Reset Rotate View or a saved view) and the desktop app renders the frame at the new angle on the render worker, the canvas draws the last frame turned to the new angle until that frame is ready. It used to draw no art until then.