diff --git a/cli/src/components/blocks/agent-branch-wrapper.tsx b/cli/src/components/blocks/agent-branch-wrapper.tsx
index dbded04ac5..46da9ea921 100644
--- a/cli/src/components/blocks/agent-branch-wrapper.tsx
+++ b/cli/src/components/blocks/agent-branch-wrapper.tsx
@@ -17,7 +17,10 @@ import { ToolBlockGroup } from './tool-block-group'
 import { useTheme } from '../../hooks/use-theme'
 import { useChatStore } from '../../state/chat-store'
 import { isTextBlock } from '../../types/chat'
-import { getAgentDisplayPrompt } from '../../utils/agent-display'
+import {
+  getAgentDisplayPrompt,
+  getBasherFinishedOutputPreview,
+} from '../../utils/agent-display'
 import { getAgentStatusInfo } from '../../utils/agent-helpers'
 import {
   processBlocks,
@@ -52,12 +55,23 @@ function getCollapsedPreview(
   agentBlock: AgentContentBlock,
   isStreaming: boolean,
   isCollapsed: boolean,
+  availableWidth: number,
 ): string {
   // No preview needed if expanded and not streaming
   if (!isStreaming && !isCollapsed) {
     return ''
   }
 
+  if (!isStreaming) {
+    const outputPreview = getBasherFinishedOutputPreview(
+      agentBlock,
+      Math.max(24, Math.min(120, availableWidth - 4)),
+    )
+    if (outputPreview) {
+      return outputPreview
+    }
+  }
+
   // For multi-prompt editors, try progress-focused preview first
   if (isMultiPromptEditor(agentBlock.agentType)) {
     const multiPromptPreview = getMultiPromptPreview(
@@ -427,7 +441,12 @@ export const AgentBranchWrapper = memo(
     const isStreaming = agentBlock.status === 'running' || agentIsStreaming
 
     // Compute collapsed preview text
-    const preview = getCollapsedPreview(agentBlock, isStreaming, isCollapsed)
+    const preview = getCollapsedPreview(
+      agentBlock,
+      isStreaming,
+      isCollapsed,
+      availableWidth,
+    )
     const displayPrompt = getAgentDisplayPrompt(agentBlock)
 
     const effectiveStatus = isStreaming ? 'running' : agentBlock.status
diff --git a/cli/src/utils/__tests__/agent-display.test.ts b/cli/src/utils/__tests__/agent-display.test.ts
index 82e410dcfc..248a7a074a 100644
--- a/cli/src/utils/__tests__/agent-display.test.ts
+++ b/cli/src/utils/__tests__/agent-display.test.ts
@@ -1,6 +1,10 @@
 import { describe, expect, test } from 'bun:test'
 
-import { getAgentDisplayPrompt } from '../agent-display'
+import {
+  getAgentDisplayPrompt,
+  getBasherFinishedOutputPreview,
+  truncateToSingleLinePreview,
+} from '../agent-display'
 
 import type { AgentContentBlock } from '../../types/chat'
 
@@ -64,3 +68,72 @@ describe('getAgentDisplayPrompt', () => {
     expect(getAgentDisplayPrompt(block)).toBeUndefined()
   })
 })
+
+describe('getBasherFinishedOutputPreview', () => {
+  test('returns undefined while basher is still running', () => {
+    const block = createAgentBlock({
+      status: 'running',
+      params: {
+        what_to_summarize: 'Report the test result',
+      },
+      blocks: [{ type: 'text', content: 'Tests passed' }],
+    })
+
+    expect(getBasherFinishedOutputPreview(block)).toBeUndefined()
+  })
+
+  test('uses finished basher text output before what_to_summarize', () => {
+    const block = createAgentBlock({
+      status: 'complete',
+      params: {
+        what_to_summarize: 'Report the test result',
+      },
+      blocks: [
+        {
+          type: 'text',
+          content: 'Tests passed\n42 assertions completed',
+          textType: 'text',
+        },
+      ],
+    })
+
+    expect(getBasherFinishedOutputPreview(block)).toBe(
+      'Tests passed 42 assertions completed',
+    )
+  })
+
+  test('falls back to command output when no text block exists', () => {
+    const block = createAgentBlock({
+      status: 'complete',
+      blocks: [
+        {
+          type: 'tool',
+          toolCallId: 'tool-1',
+          toolName: 'run_terminal_command',
+          input: { command: 'git status --short' },
+          output: ' M cli/src/app.tsx\n',
+        },
+      ],
+    })
+
+    expect(getBasherFinishedOutputPreview(block)).toBe('M cli/src/app.tsx')
+  })
+
+  test('ignores non-basher output', () => {
+    const block = createAgentBlock({
+      agentType: 'code-searcher',
+      status: 'complete',
+      blocks: [{ type: 'text', content: 'Search results' }],
+    })
+
+    expect(getBasherFinishedOutputPreview(block)).toBeUndefined()
+  })
+})
+
+describe('truncateToSingleLinePreview', () => {
+  test('collapses whitespace and truncates to the requested length', () => {
+    expect(truncateToSingleLinePreview('one\ntwo   three four', 13)).toBe(
+      'one two th...',
+    )
+  })
+})
diff --git a/cli/src/utils/agent-display.ts b/cli/src/utils/agent-display.ts
index 18c3668fd4..b91545cea3 100644
--- a/cli/src/utils/agent-display.ts
+++ b/cli/src/utils/agent-display.ts
@@ -1,6 +1,30 @@
 import { getAgentBaseName } from './message-block-helpers'
 
-import type { AgentContentBlock } from '../types/chat'
+import type {
+  AgentContentBlock,
+  TextContentBlock,
+  ToolContentBlock,
+} from '../types/chat'
+
+const DEFAULT_BASHER_OUTPUT_PREVIEW_MAX_LENGTH = 120
+const PREVIEW_ELLIPSIS = '...'
+
+export function truncateToSingleLinePreview(
+  text: string,
+  maxLength = DEFAULT_BASHER_OUTPUT_PREVIEW_MAX_LENGTH,
+): string | undefined {
+  const singleLine = text.replace(/\s+/g, ' ').trim()
+  if (!singleLine) {
+    return undefined
+  }
+
+  if (singleLine.length <= maxLength) {
+    return singleLine
+  }
+
+  const previewLength = Math.max(0, maxLength - PREVIEW_ELLIPSIS.length)
+  return `${singleLine.slice(0, previewLength).trimEnd()}${PREVIEW_ELLIPSIS}`
+}
 
 export function getAgentDisplayPrompt(
   agentBlock: AgentContentBlock,
@@ -19,3 +43,45 @@ export function getAgentDisplayPrompt(
     ? whatToSummarize.trim()
     : undefined
 }
+
+export function getBasherFinishedOutputPreview(
+  agentBlock: AgentContentBlock,
+  maxLength = DEFAULT_BASHER_OUTPUT_PREVIEW_MAX_LENGTH,
+): string | undefined {
+  if (
+    getAgentBaseName(agentBlock.agentType) !== 'basher' ||
+    agentBlock.status === 'running'
+  ) {
+    return undefined
+  }
+
+  const blocks = agentBlock.blocks ?? []
+  return (
+    truncateToSingleLinePreview(getTextOutput(blocks), maxLength) ??
+    truncateToSingleLinePreview(getCommandOutput(blocks), maxLength)
+  )
+}
+
+function getTextOutput(
+  blocks: NonNullable<AgentContentBlock['blocks']>,
+): string {
+  return blocks
+    .filter(
+      (block): block is TextContentBlock =>
+        block.type === 'text' && block.textType !== 'reasoning',
+    )
+    .map((block) => block.content)
+    .join('\n')
+}
+
+function getCommandOutput(
+  blocks: NonNullable<AgentContentBlock['blocks']>,
+): string {
+  return blocks
+    .filter(
+      (block): block is ToolContentBlock =>
+        block.type === 'tool' && block.toolName === 'run_terminal_command',
+    )
+    .map((block) => block.output ?? '')
+    .join('\n')
+}