fix(desktop): keep envelope errors and sealed calls settled outside the tool row

Three consumers still read `result === undefined` as an open call or an error without text after the result and display-hint split.

The tool row lost the event's error explanation when the result carried none: `toolErrorText` now reads `toolResultMetadata.error` / `.message` when `isError` is set, and `toolStatus` runs the error path for sealed error rows so an envelope-only read miss stays on the notice tier. The turn-activity signature and wait narration count a sealed call as settled. Onboarding's start-with-connections offer withdraws once a connection wait is sealed.

Four tests fail on 235ec0f and pass here.

apps/desktop/src/components/assistant-ui/thread/turn-activity.test.ts

@@ -53,6 +53,15 @@ describe('toolNarratesWait', () => {
     expect(toolNarratesWait([call('react_to_message', false)])).toBe(false)
   })
 
+  it('does not defer to a call sealed without a result', () => {
+    const sealed = { completedAt: 5, toolName: 'terminal', type: 'tool-call' }
+
+    expect(toolNarratesWait([text('working'), sealed])).toBe(false)
+    expect(activitySignature([text('working'), sealed])).not.toBe(
+      activitySignature([text('working'), call('terminal', false)])
+    )
+  })
+
   it('defers to a call in flight even when a later part follows it', () => {
     // Tail-part-only detection missed this: a turn that starts prose while a
     // call is still running showed the row under the tool's own timer.

apps/desktop/src/components/assistant-ui/thread/turn-activity.ts

@@ -11,12 +11,16 @@ import { isSilentTool } from '@/lib/tool-render-class'
 export const TURN_QUIET_S = 2
 
 export interface ActivityPart {
+  completedAt?: number
   result?: unknown
   text?: unknown
   toolName?: string
   type: string
 }
 
+// A sealed call carries a completion marker and no result.
+const settled = (part: ActivityPart): boolean => part.result !== undefined || part.completedAt !== undefined
+
 /**
  * What the tail message has produced so far, as a value that changes exactly
  * when the turn makes visible progress.
@@ -36,7 +40,7 @@ export function activitySignature(content: readonly ActivityPart[]): string {
       textLength += part.text.length
     }
 
-    if (part.type === 'tool-call' && part.result !== undefined) {
+    if (part.type === 'tool-call' && settled(part)) {
       settledTools += 1
     }
   }
@@ -54,7 +58,5 @@ export function activitySignature(content: readonly ActivityPart[]): string {
  * of those is as unnarrated as a wait on nothing at all.
  */
 export function toolNarratesWait(content: readonly ActivityPart[]): boolean {
-  return content.some(
-    part => part.type === 'tool-call' && part.result === undefined && !isSilentTool(part.toolName ?? '')
-  )
+  return content.some(part => part.type === 'tool-call' && !settled(part) && !isSilentTool(part.toolName ?? ''))
 }

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

@@ -117,6 +117,38 @@ describe('buildToolView error confidence', () => {
   })
 })
 
+describe('buildToolView envelope errors', () => {
+  it('shows the event error when the result carries no explanation', () => {
+    const view = buildToolView(
+      part({
+        isError: true,
+        result: 'partial output',
+        toolName: 'terminal',
+        toolResultMetadata: { error: 'killed by signal 9' }
+      }),
+      ''
+    )
+
+    expect(view.status).toBe('error')
+    expect(view.subtitle).toBe('killed by signal 9')
+  })
+
+  it('keeps an envelope-only read miss on the notice tier', () => {
+    const view = buildToolView(
+      part({
+        isError: true,
+        result: undefined,
+        completedAt: 5,
+        toolName: 'read_file',
+        toolResultMetadata: { error: 'File not found: /repo/missing.ts' }
+      }),
+      ''
+    )
+
+    expect(view.status).toBe('notice')
+  })
+})
+
 describe('buildToolView browser_exec step label', () => {
   const bexec = (code: string) =>
     buildToolView(part({ args: { code }, result: undefined, toolName: 'browser_exec' }), '')

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

@@ -5,7 +5,7 @@ import { normalizeExternalUrl } from '@/lib/external-link'
 import { summarizeShellCommand } from '@/lib/summarize-command'
 import { capitalize, firstStringField, normalize } from '@/lib/text'
 import { isCardTool, isFileEditTool, isSilentTool } from '@/lib/tool-render-class'
-import { toolResultRecord } from '@/lib/tool-result-metadata'
+import { envelopeErrorText, toolResultRecord } from '@/lib/tool-result-metadata'
 import { extractToolErrorMessage, formatToolResultSummary } from '@/lib/tool-result-summary'
 
 import { skillActivityTitle } from '../skill-activity'
@@ -662,7 +662,12 @@ function toolErrorText(part: ToolPart, result: Record<string, unknown>): string
   const extractedError = extractToolErrorMessage(part.result)
 
   if (part.isError) {
-    return extractedError || (typeof part.result === 'string' && part.result.trim()) || 'Tool returned an error.'
+    return (
+      extractedError ||
+      envelopeErrorText(part.toolResultMetadata) ||
+      (typeof part.result === 'string' && part.result.trim()) ||
+      'Tool returned an error.'
+    )
   }
 
   if (extractedError) {
@@ -696,8 +701,12 @@ function toolErrorText(part: ToolPart, result: Record<string, unknown>): string
 }
 
 function toolStatus(part: ToolPart, resultRecord: Record<string, unknown>): ToolStatus {
-  if (part.result === undefined) {
-    return part.completedAt === undefined ? 'running' : part.isError ? 'error' : 'warning'
+  if (part.result === undefined && part.completedAt === undefined) {
+    return 'running'
+  }
+
+  if (part.result === undefined && !part.isError) {
+    return 'warning'
   }
 
   // Explicit success wins over isError / nested-error heuristics. Memory writes

apps/desktop/src/lib/first-build-start.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, it } from 'vitest'
+
+import type { ChatMessagePart } from '@/lib/chat-messages'
+
+import { canStartWithConnections } from './first-build-start'
+
+const wait = (overrides: Partial<Extract<ChatMessagePart, { type: 'tool-call' }>>): ChatMessagePart =>
+  ({
+    type: 'tool-call',
+    toolCallId: 'wait-1',
+    toolName: 'manage_connections',
+    args: { action: 'wait' },
+    ...overrides
+  }) as ChatMessagePart
+
+describe('canStartWithConnections', () => {
+  it('offers the start while a connection wait is in flight', () => {
+    expect(canStartWithConnections(wait({}))).toBe(true)
+  })
+
+  it('withdraws the start once the wait is sealed without a result', () => {
+    expect(canStartWithConnections(wait({ completedAt: 5 }))).toBe(false)
+  })
+})

apps/desktop/src/lib/first-build-start.ts

@@ -25,7 +25,7 @@ export function canStartWithConnections(part: ChatMessagePart): boolean {
   const output = recordOf(part.result)
 
   if (action === 'wait') {
-    return part.result === undefined || output.status === 'pending'
+    return (part.result === undefined && part.completedAt === undefined) || output.status === 'pending'
   }
 
   return (

apps/desktop/src/lib/tool-result-metadata.ts

@@ -32,3 +32,10 @@ export function toolResultRecord(source: ToolResultSource): Record<string, unkno
   // Authoritative result fields win over fallible/abbreviated display hints.
   return { ...source.toolResultMetadata, ...record }
 }
+
+/** The event's own account of a failure, for calls whose result carries none. */
+export function envelopeErrorText(metadata: ToolResultMetadata | undefined): string {
+  const text = typeof metadata?.error === 'string' ? metadata.error : metadata?.message
+
+  return text?.trim() ?? ''
+}