fix(desktop): keep code and diffs out of the tool overflow window

apps/desktop/src/components/assistant-ui/tool/fallback.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest'
 
-import { shouldBoundToolGroup, technicalTrace, UNBOUNDABLE_TOOLS } from './fallback'
+import { isUnboundableTool, shouldBoundToolGroup, technicalTrace } from './fallback'
+import { isFileEditTool } from './fallback-model'
 
 describe('shouldBoundToolGroup', () => {
   it('bounds long runs of ordinary tool calls', () => {
@@ -16,10 +17,34 @@ describe('shouldBoundToolGroup', () => {
   })
 })
 
-describe('UNBOUNDABLE_TOOLS', () => {
+describe('isUnboundableTool', () => {
   it('exempts clarify forms and generated images from the window', () => {
-    expect(UNBOUNDABLE_TOOLS.has('clarify')).toBe(true)
-    expect(UNBOUNDABLE_TOOLS.has('image_generate')).toBe(true)
+    expect(isUnboundableTool('clarify')).toBe(true)
+    expect(isUnboundableTool('image_generate')).toBe(true)
+  })
+
+  it('exempts tools whose body is a code block the user reads', () => {
+    expect(isUnboundableTool('execute_code')).toBe(true)
+    expect(isUnboundableTool('read_file')).toBe(true)
+  })
+
+  // The window clips a diff to a ~2-row viewport, so every tool that renders
+  // one has to be exempt. Derived from isFileEditTool rather than re-listed,
+  // so a newly supported edit tool can't be exempt in one place and clipped
+  // in the other.
+  it('exempts every file-edit tool, so diffs are never clipped', () => {
+    for (const toolName of ['edit_file', 'patch', 'write_file']) {
+      expect(isFileEditTool(toolName)).toBe(true)
+      expect(isUnboundableTool(toolName)).toBe(true)
+    }
+  })
+
+  // Console output is a log tail: the last lines are the ones that matter,
+  // which is exactly what the bounded window pins. Keeping it boundable is
+  // what stops the exemption from swallowing the feature whole.
+  it('still bounds console output and other ordinary rows', () => {
+    expect(isUnboundableTool('terminal')).toBe(false)
+    expect(isUnboundableTool('web_search')).toBe(false)
   })
 })
 

apps/desktop/src/components/assistant-ui/tool/fallback.tsx

@@ -673,10 +673,30 @@ function TerminalTranscript({ command, exitCode }: TerminalTranscriptProps) {
 // auto-scrolling window; fewer than this stays a plain inline stack.
 const TOOL_GROUP_SCROLL_THRESHOLD = 3
 
-// Tools whose body (an interactive form, a full-size image) must never be
-// trapped behind the window's max-height + fade mask. A run holding any of
-// them stays a plain, fully-visible stack no matter how long it is.
-export const UNBOUNDABLE_TOOLS = new Set(['clarify', 'image_generate'])
+// Tools whose body (an interactive form, a full-size image, a syntax-
+// highlighted code/diff block) must never be trapped behind the window's
+// max-height + fade mask. A run holding any of them stays a plain, fully-
+// visible stack no matter how long it is.
+//
+// A row rendered by ToolEntry carries `data-tool-row`, so once the user
+// expands it the `:has([data-tool-row][data-tool-open])` rule in styles.css
+// lifts the cap on its own. That escape hatch is why most tools are safe to
+// bound. These are the ones it cannot reach:
+//
+//   - `clarify` / `image_generate` render their own components and never emit
+//     `data-tool-row`, so no amount of expanding frees them.
+//   - the code tools *do* emit it, but their body is a code block the user
+//     reads rather than a one-line status — peering at a diff through a
+//     ~2-row viewport until you think to expand it is the bug. Console output
+//     (`terminal`) stays boundable: it's a log tail, and the last lines are
+//     the ones that matter, which is exactly what the window pins.
+const CODE_BODY_TOOLS = ['execute_code', 'read_file']
+
+const UNBOUNDABLE_TOOLS = new Set(['clarify', 'image_generate', ...CODE_BODY_TOOLS])
+
+export function isUnboundableTool(toolName: string): boolean {
+  return UNBOUNDABLE_TOOLS.has(toolName) || isFileEditTool(toolName)
+}
 
 export function shouldBoundToolGroup(childCount: number, hasUnboundable: boolean) {
   return childCount >= TOOL_GROUP_SCROLL_THRESHOLD && !hasUnboundable
@@ -761,7 +781,7 @@ export const ToolGroupSlot: FC<PropsWithChildren<{ endIndex: number; startIndex:
   const hasUnboundable = useAuiState(s =>
     s.message.parts
       .slice(Math.max(0, startIndex), endIndex + 1)
-      .some(part => part.type === 'tool-call' && UNBOUNDABLE_TOOLS.has(part.toolName))
+      .some(part => part.type === 'tool-call' && isUnboundableTool(part.toolName))
   )
 
   const enterRef = useEnterAnimation(messageRunning, `tool-group:${messageId}:${startIndex}`)