diff --git a/apps/web/tests/code-mode-fixture.snapshot.ts b/apps/web/tests/code-mode-fixture.snapshot.ts
index f53777fff8..ce5a98b2eb 100644
--- a/apps/web/tests/code-mode-fixture.snapshot.ts
+++ b/apps/web/tests/code-mode-fixture.snapshot.ts
@@ -5,7 +5,7 @@
 // the code-variant parent row titled by the model-authored description, its
 // three always-visible nested sub-rows (bash through the sample registration,
 // read through GenericToolCard, the failing read wearing the error state),
-// the expanded program body, details-panel resolution of a sub-callId, and
+// the expanded program body, inert bash / file-link sub-row gestures, and
 // the trajectory/waterfall tabs' sub-call cells and timing lanes.
 import { readFileSync } from 'node:fs'
 import { join } from 'node:path'
@@ -152,7 +152,7 @@ it('renders the fixture run_code turn: code parent row, nested sub-rows, error s
   `)
 })
 
-it('expands the code row into the program body and resolves a sub-row through the details panel', async () => {
+it('expands the code row into the program body; sub-row clicks do not open details', async () => {
   boot()
   await openFixtureSession()
 
@@ -171,26 +171,28 @@ it('expands the code row into the program body and resolves a sub-row through th
     }
   })
 
-  // Sub-row click → details panel resolves the sub-callId with FULL output.
+  // Tool rows no longer drive the details panel: bash is inert, file paths
+  // are host-open links (fixture openPath is a no-op success).
   const nest = document.querySelector('[data-subcalls]')
   if (nest === null) throw new Error('sub-call nest missing')
   const bashRow = nest.querySelector('[data-sample="bash-global"]')
   if (bashRow === null) throw new Error('bash sample sub-row missing')
+  const fileLink = nest.querySelector('button')
+  if (fileLink === null) throw new Error('file-path summary link missing on a read sub-row')
+  const frame = document.querySelector('[data-details-collapsed]')
+  if (frame === null) throw new Error('app frame missing')
+  expect(frame.getAttribute('data-details-collapsed')).toBe('true')
   fireEvent.click(bashRow)
-  const details = await screen.findByText('Input')
-  const panel = details.closest('[class*="root"]')
-  if (panel === null) throw new Error('details panel missing')
+  expect(frame.getAttribute('data-details-collapsed')).toBe('true')
+  fireEvent.click(fileLink)
+  expect(frame.getAttribute('data-details-collapsed')).toBe('true')
   expect({
-    title: visibleText(within(panel as HTMLElement).getByText('bash')),
-    inputEchoesArgs: visibleText(panel).includes('ls notes'),
-    outputComplete: visibleText(panel).includes('demo.txt new-demo.txt')
-      || visibleText(panel).includes('demo.txt\nnew-demo.txt')
-      || (panel.textContent ?? '').includes('demo.txt\nnew-demo.txt'),
+    fileLink: visibleText(fileLink),
+    detailsCollapsed: frame.getAttribute('data-details-collapsed'),
   }).toMatchInlineSnapshot(`
     {
-      "inputEchoesArgs": true,
-      "outputComplete": true,
-      "title": "bash",
+      "detailsCollapsed": "true",
+      "fileLink": "notes/demo.txt",
     }
   `)
 })
diff --git a/apps/web/tests/code-mode-round.e2e.ts b/apps/web/tests/code-mode-round.e2e.ts
index 32c51a2a2a..a7f493e448 100644
--- a/apps/web/tests/code-mode-round.e2e.ts
+++ b/apps/web/tests/code-mode-round.e2e.ts
@@ -118,19 +118,14 @@ describe('web e2e: Code Mode round renders nested sub-calls', () => {
     expect(await nest.locator('[data-state="error"]').count()).toBeGreaterThanOrEqual(1)
   }, 60_000)
 
-  it.skipIf(MODE === 'record')('a sub-row click opens the details panel on the sub-call material', async () => {
+  it.skipIf(MODE === 'record')('a bash sub-row click leaves the details panel collapsed', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-code-mode-details'))
     const nest = page.locator('[data-subcalls]').first()
+    const frame = page.locator('[data-details-collapsed], [class*="frame"]').first()
+    expect(await frame.getAttribute('data-details-collapsed')).not.toBeNull()
     await nest.locator('[data-sample="bash-global"]').first().click()
-    // The details column opens (width > 0) and shows the sub-call's complete
-    // output — the full-content log contract, no truncation marker anywhere.
-    await page.waitForFunction(() => {
-      const frame = document.querySelector('[class*="frame"]')
-      if (frame === null) return false
-      return Number(getComputedStyle(frame).gridTemplateColumns.split(' ').pop()!.replace('px', '')) > 0
-    }, undefined, { timeout: 10_000 })
-    await expect.poll(() => page.getByText('CODE_ROUND_OK', { exact: false }).count(), { timeout: 5_000 })
-      .toBeGreaterThanOrEqual(1)
+    // Tool rows no longer open details; the column stays width 0.
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
   })
 
   it.skipIf(MODE === 'record')('matches the conversation aria golden with stable anchors', async () => {
diff --git a/apps/web/tests/navigation-panes.e2e.ts b/apps/web/tests/navigation-panes.e2e.ts
index bbae7363df..a27a61f80f 100644
--- a/apps/web/tests/navigation-panes.e2e.ts
+++ b/apps/web/tests/navigation-panes.e2e.ts
@@ -1,12 +1,11 @@
 // Web e2e scenarios: navigation & panes — the view tabs (Trajectory /
-// Waterfall), the details column, and sidebar search, all over ONE rich
-// two-turn seeded fixture rendered purely from the log (the seeded-history
-// pattern: zero model calls in replay, so every surface here is the client
-// fold + host history RPC, not replay binding). The seed is recorded live
-// under the standard discipline: turn 1 produces a bash call plus two
-// parallel reads in one assistant message (tool-call density for the
-// trajectory/waterfall lanes and a details-capable bash row), turn 2 a
-// markdown-rich reply (a second turn so the waterfall has two lanes).
+// Waterfall) and sidebar search, all over ONE rich two-turn seeded fixture
+// rendered purely from the log (the seeded-history pattern: zero model calls
+// in replay, so every surface here is the client fold + host history RPC,
+// not replay binding). The seed is recorded live under the standard
+// discipline: turn 1 produces a bash call plus two parallel reads in one
+// assistant message (tool-call density for the trajectory/waterfall lanes),
+// turn 2 a markdown-rich reply (a second turn so the waterfall has two lanes).
 import { mkdir, readFile, writeFile } from 'node:fs/promises'
 import { fileURLToPath } from 'node:url'
 import { join } from 'node:path'
@@ -25,7 +24,6 @@ const SNAPSHOT_DIR = fileURLToPath(new URL('./snapshots/navigation-panes', impor
 const SEED = join(SNAPSHOT_DIR, 'seed.jsonl')
 const TRAJECTORY_EXPECTED = join(SNAPSHOT_DIR, 'trajectory.expected.md')
 const WATERFALL_EXPECTED = join(SNAPSHOT_DIR, 'waterfall.expected.md')
-const DETAILS_EXPECTED = join(SNAPSHOT_DIR, 'details-open.expected.md')
 const MODE = webSnapshotMode()
 const SEED_ID = 'navigation-panes-web-e2e'
 
@@ -155,36 +153,27 @@ describe('web e2e: navigation & panes over a rich seeded session', () => {
     await compareOrRefreshGolden(WATERFALL_EXPECTED, snapshot, MODE)
   }, 60_000)
 
-  it.skipIf(MODE === 'record')('opens the details column from the bash row and closes it', async () => {
+  it.skipIf(MODE === 'record')('bash and file-path rows leave the details column collapsed', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-navigation-details'))
     await page.getByRole('tab', { name: 'Chat' }).click()
-    // The bash toolview row routes its click to openDetails (read rows are
-    // expand-in-place instead — the seeded-history scenario owns that fold).
     const bashRow = page.locator('[data-sample="bash-global"]').first()
     await bashRow.waitFor({ timeout: 15_000 })
-    // Open/closed is the frame's collapsed attribute: the column collapses to
-    // width 0 but its subtree deliberately never unmounts (hidden, not
-    // absent), so element presence/visibility cannot express the state.
     const frame = page.locator('[data-details-collapsed], [class*="frame"]').first()
     expect(await frame.getAttribute('data-details-collapsed')).not.toBeNull()
     await bashRow.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 10_000 }).toBeNull()
-    // The open panel shows the selected call's name, arguments, and durable
-    // result (NAVIGATION_OK appears in the chat row too, hence >= 2 total).
-    await expect.poll(() => page.getByText('NAVIGATION_OK', { exact: false }).count(), { timeout: 10_000 }).toBeGreaterThanOrEqual(2)
-    // Golden of the open panel: tool name header, Input args, Output result.
-    const snapshot = (await captureStableAria(page, '[class*="detailsCol"]', scaffold.workspaceCwd))
-      .split(SEED_ID).join('{{seededId}}')
-    await compareOrRefreshGolden(DETAILS_EXPECTED, snapshot, MODE)
-    await page.getByRole('button', { name: '关闭详情' }).click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 10_000 }).not.toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
+    // Read summaries are host-open file links; they also must not open details.
+    const fileLink = page.locator('[data-variant="read"] button').first()
+    await fileLink.waitFor({ timeout: 10_000 })
+    await fileLink.click()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
   }, 60_000)
 
   it.skipIf(MODE === 'record')('issued zero model calls and stayed clean', async () => {
     expect(tripwire.pageErrors).toEqual([])
     expect(tripwire.warnings).toEqual([])
     await assertFixtureInventory(SNAPSHOT_DIR, [
-      'seed.jsonl', 'trajectory.expected.md', 'waterfall.expected.md', 'details-open.expected.md',
+      'seed.jsonl', 'trajectory.expected.md', 'waterfall.expected.md',
     ])
   })
 })
diff --git a/apps/web/tests/seeded-history.e2e.ts b/apps/web/tests/seeded-history.e2e.ts
index 265bb20d07..0742612e29 100644
--- a/apps/web/tests/seeded-history.e2e.ts
+++ b/apps/web/tests/seeded-history.e2e.ts
@@ -103,21 +103,19 @@ describe('web e2e: seeded history renders through cold resume', () => {
     await compareOrRefreshGolden(UI_EXPECTED, snapshot, MODE)
   })
 
-  it.skipIf(MODE === 'record')('expands and collapses a tool row rebuilt from the cold log', async () => {
+  it.skipIf(MODE === 'record')('file-path tool rows rebuilt from the cold log stay details-inert', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-seeded-toolrow'))
-    // Interaction over cold-resumed history: read rows are expand-in-place
-    // rows (rowExpands routes the click to toggleExpand, not openDetails), so
-    // the gesture under test is the inline fold over log-rebuilt content.
-    // Runs after the golden capture; still zero model calls.
-    const row = page.locator('[data-variant] [data-clickable][role="button"]').first()
-    await row.waitFor({ timeout: 10_000 })
-    expect(await row.getAttribute('aria-expanded')).toBe('false')
-    await row.click()
-    await expect.poll(() => row.getAttribute('aria-expanded'), { timeout: 5_000 }).toBe('true')
-    // The expanded body renders the recorded tool result (a.txt's contents).
-    await expect.poll(() => page.getByText('alpha', { exact: false }).count(), { timeout: 5_000 }).toBeGreaterThan(0)
-    await row.click()
-    await expect.poll(() => row.getAttribute('aria-expanded'), { timeout: 5_000 }).toBe('false')
+    // Interaction over cold-resumed history: read summaries are host-open
+    // file links (not expand-in-place / not details). Runs after the golden
+    // capture; still zero model calls.
+    const fileLink = page.locator('[data-variant="read"] button').first()
+    await fileLink.waitFor({ timeout: 10_000 })
+    const frame = page.locator('[data-details-collapsed], [class*="frame"]').first()
+    expect(await frame.getAttribute('data-details-collapsed')).not.toBeNull()
+    await fileLink.click()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
+    // Path label survives from the recorded args (a.txt).
+    await expect.poll(() => page.getByText('a.txt', { exact: false }).count(), { timeout: 5_000 }).toBeGreaterThan(0)
   })
 
   it.skipIf(MODE === 'record')('issued zero model calls and stayed clean', async () => {
diff --git a/apps/web/tests/smoke-real.e2e.ts b/apps/web/tests/smoke-real.e2e.ts
index 58db1beafd..47d6ea81f7 100644
--- a/apps/web/tests/smoke-real.e2e.ts
+++ b/apps/web/tests/smoke-real.e2e.ts
@@ -7,7 +7,7 @@
 //
 // Selector convention: CSS Modules hash as [hash]_[local], so class-substring
 // selectors are unreliable — anchor on data-* attributes (data-variant /
-// data-clickable / data-sample) or visible text. The one [class*=] use below
+// data-sample) or visible text. The one [class*=] use below
 // (frame/handle) rides local names that survive hashing as suffixes; prefer
 // data-* for anything new.
 //
@@ -448,7 +448,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY || notReady.length > 0)('web smoke
     await screen(page, '07-back-to-chat')
   })
 
-  it('5 bash differential rendering: tool row click opens the details column', async () => {
+  it('5 bash differential rendering: tool row click leaves the details column collapsed', async () => {
     onTestFailed(() => saveFailureShot(page, 'w5-tool-details'))
     const input = page.locator('textarea').first()
     await input.fill('请用 bash 工具运行命令 echo w5marker 然后告诉我结果')
@@ -462,13 +462,9 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY || notReady.length > 0)('web smoke
     await screen(page, '08-bash-round')
     expect(await detailsTrack(page)).toBe(0)
     await toolRow.click()
-    // Selection channel: click writes selection + layout.openDetails.
-    await page.waitForFunction(() => {
-      const frame = document.querySelector('[class*="frame"]')
-      if (frame === null) return false
-      return Number(getComputedStyle(frame).gridTemplateColumns.split(' ').pop()!.replace('px', '')) > 0
-    }, undefined, { timeout: 10_000 })
-    await screen(page, '09-details-open')
+    // Tool rows no longer drive layout.openDetails; the column stays closed.
+    expect(await detailsTrack(page)).toBe(0)
+    await screen(page, '09-details-closed')
   }, 150_000)
 
   it('6 sidebar drag widens the column and persists across reload', async () => {
diff --git a/apps/web/tests/snapshots/navigation-panes/details-open.expected.md b/apps/web/tests/snapshots/navigation-panes/details-open.expected.md
deleted file mode 100644
index d69a95eb2d..0000000000
--- a/apps/web/tests/snapshots/navigation-panes/details-open.expected.md
+++ /dev/null
@@ -1,5 +0,0 @@
-- text: bash
-- button "关闭详情"
-- text: Input
-- code: "{ \"command\": \"echo NAVIGATION_OK\", \"description\": \"Print NAVIGATION_OK\" }"
-- text: Output NAVIGATION_OK
diff --git a/packages/host/apiproxy/src/native-command.ts b/packages/host/apiproxy/src/native-command.ts
new file mode 100644
index 0000000000..0efe9679d8
--- /dev/null
+++ b/packages/host/apiproxy/src/native-command.ts
@@ -0,0 +1,38 @@
+/** Shared no-shell `execFile` runner for native host dialogs and openers. */
+
+import { execFile } from 'node:child_process'
+
+/** Testable command boundary; native implementations never invoke a shell. */
+export type NativeCommandRunner = (
+  command: string,
+  args: readonly string[],
+  signal: AbortSignal,
+) => Promise<{ stdout: string; stderr: string }>
+
+/**
+ * Run a host command with utf8 stdio, abort propagation, and Windows hide.
+ * @param command - executable path or PATH name.
+ * @param args - argv (never a shell string).
+ * @param signal - caller/connection lifetime; abort terminates the child.
+ * @returns captured stdout/stderr on exit 0.
+ */
+export const runNativeCommand: NativeCommandRunner = (command, args, signal) =>
+  new Promise((resolve, reject) => {
+    execFile(
+      command,
+      [...args],
+      { encoding: 'utf8', signal, windowsHide: true },
+      (error, stdout, stderr) => {
+        if (error !== null) {
+          const failure = Object.assign(new Error(error.message, { cause: error }), {
+            code: error.code,
+            stdout,
+            stderr,
+          })
+          reject(failure)
+          return
+        }
+        resolve({ stdout, stderr })
+      },
+    )
+  })
diff --git a/packages/host/apiproxy/src/native-directory-picker.ts b/packages/host/apiproxy/src/native-directory-picker.ts
index 8bc0bc99ce..0ddba8e30d 100644
--- a/packages/host/apiproxy/src/native-directory-picker.ts
+++ b/packages/host/apiproxy/src/native-directory-picker.ts
@@ -1,13 +1,9 @@
 /** Cross-platform native single-directory picker used by the local GUI carrier. */
 
-import { execFile } from 'node:child_process'
+import { runNativeCommand, type NativeCommandRunner } from './native-command.ts'
 
 /** Testable command boundary; native implementations never invoke a shell. */
-export type DirectoryPickerRunner = (
-  command: string,
-  args: readonly string[],
-  signal: AbortSignal,
-) => Promise<{ stdout: string; stderr: string }>
+export type DirectoryPickerRunner = NativeCommandRunner
 
 /** Injectable platform facts for deterministic adapter tests. */
 export interface DirectoryPickerInternals {
@@ -15,27 +11,6 @@ export interface DirectoryPickerInternals {
   run?: DirectoryPickerRunner
 }
 
-const runCommand: DirectoryPickerRunner = (command, args, signal) =>
-  new Promise((resolve, reject) => {
-    execFile(
-      command,
-      [...args],
-      { encoding: 'utf8', signal, windowsHide: true },
-      (error, stdout, stderr) => {
-        if (error !== null) {
-          const failure = Object.assign(new Error(error.message, { cause: error }), {
-            code: error.code,
-            stdout,
-            stderr,
-          })
-          reject(failure)
-          return
-        }
-        resolve({ stdout, stderr })
-      },
-    )
-  })
-
 function outputPath(stdout: string): string | null {
   const path = stdout.replace(/[\r\n]+$/, '')
   return path === '' ? null : path
@@ -72,7 +47,7 @@ export async function pickNativeDirectory(
   internals: DirectoryPickerInternals = {},
 ): Promise<string | null> {
   const platform = internals.platform ?? process.platform
-  const run = internals.run ?? runCommand
+  const run = internals.run ?? runNativeCommand
 
   if (platform === 'darwin') {
     try {
diff --git a/packages/host/apiproxy/src/native-path-opener.ts b/packages/host/apiproxy/src/native-path-opener.ts
index 24ee444a07..15a6d7a73b 100644
--- a/packages/host/apiproxy/src/native-path-opener.ts
+++ b/packages/host/apiproxy/src/native-path-opener.ts
@@ -1,13 +1,9 @@
 /** Cross-platform open-with-default-application used by the local GUI carrier. */
 
-import { execFile } from 'node:child_process'
+import { runNativeCommand, type NativeCommandRunner } from './native-command.ts'
 
 /** Testable command boundary; native implementations never invoke a shell. */
-export type PathOpenerRunner = (
-  command: string,
-  args: readonly string[],
-  signal: AbortSignal,
-) => Promise<{ stdout: string; stderr: string }>
+export type PathOpenerRunner = NativeCommandRunner
 
 /** Injectable platform facts for deterministic adapter tests. */
 export interface PathOpenerInternals {
@@ -15,27 +11,6 @@ export interface PathOpenerInternals {
   run?: PathOpenerRunner
 }
 
-const runCommand: PathOpenerRunner = (command, args, signal) =>
-  new Promise((resolve, reject) => {
-    execFile(
-      command,
-      [...args],
-      { encoding: 'utf8', signal, windowsHide: true },
-      (error, stdout, stderr) => {
-        if (error !== null) {
-          const failure = Object.assign(new Error(error.message, { cause: error }), {
-            code: error.code,
-            stdout,
-            stderr,
-          })
-          reject(failure)
-          return
-        }
-        resolve({ stdout, stderr })
-      },
-    )
-  })
-
 /** PowerShell single-quoted literal (doubles embedded quotes). */
 function powershellLiteral(path: string): string {
   return `'${path.replace(/'/g, "''")}'`
@@ -53,7 +28,7 @@ export async function openNativePath(
   internals: PathOpenerInternals = {},
 ): Promise<void> {
   const platform = internals.platform ?? process.platform
-  const run = internals.run ?? runCommand
+  const run = internals.run ?? runNativeCommand
 
   if (platform === 'darwin') {
     await run('open', [path], signal)
diff --git a/packages/host/apiproxy/tests/fetch-carrier.spec.ts b/packages/host/apiproxy/tests/fetch-carrier.spec.ts
index b1f86d3b79..c67eeb9fc5 100644
--- a/packages/host/apiproxy/tests/fetch-carrier.spec.ts
+++ b/packages/host/apiproxy/tests/fetch-carrier.spec.ts
@@ -208,6 +208,18 @@ describe('unary round trip (handler ⇄ client, no network)', () => {
     expect(response.result).toEqual({ ok: true, value: { path: '/tmp/project' } })
   })
 
+  it('round-trips host.openPath through the wire form', async () => {
+    const api = fakeApi()
+    let opened: string | undefined
+    api.host.openPath = async (request) => {
+      opened = request.payload.path
+      return { rpcId: request.rpcId, result: { ok: true, value: { opened: true as const } } }
+    }
+    const response = await client(api).host.openPath({ path: '/tmp/a.txt' })
+    expect(opened).toBe('/tmp/a.txt')
+    expect(response.result).toEqual({ ok: true, value: { opened: true } })
+  })
+
   it('round-trips command.list / command.execute / skill.list through the wire form', async () => {
     const c = client()
     const list = await c.commands.list({ sessionId: 's' as never })
diff --git a/packages/host/apiproxy/tests/native-path-opener.spec.ts b/packages/host/apiproxy/tests/native-path-opener.spec.ts
index c3612921a1..c8622002e2 100644
--- a/packages/host/apiproxy/tests/native-path-opener.spec.ts
+++ b/packages/host/apiproxy/tests/native-path-opener.spec.ts
@@ -47,7 +47,18 @@ describe('native path opener', () => {
       .rejects.toThrow('unsupported on freebsd')
   })
 
-  it('runs the default command adapter without a shell', async () => {
+  it('uses the current process platform when no platform override is supplied', async () => {
+    const run = vi.fn<PathOpenerRunner>(async () => ({ stdout: '', stderr: '' }))
+    await openNativePath('/tmp/platform-default.txt', signal(), { run })
+    const expected = process.platform === 'win32'
+      ? 'powershell.exe'
+      : process.platform === 'linux'
+        ? 'xdg-open'
+        : 'open'
+    expect(run.mock.calls[0]?.[0]).toBe(expected)
+  })
+
+  it('runs the default command adapter without a shell and preserves command failures', async () => {
     execFileMock.mockImplementationOnce((_command, _args, _options, callback) => {
       callback(null, '', '')
     })
@@ -58,5 +69,14 @@ describe('native path opener', () => {
     expect(options.encoding).toBe('utf8')
     expect(options.windowsHide).toBe(true)
     expect(options.signal).toBeInstanceOf(AbortSignal)
+
+    const commandError = Object.assign(new Error('open failed'), { code: 1 })
+    execFileMock.mockImplementationOnce((_command, _args, _options, callback) => {
+      callback(commandError, 'partial output', 'failure details')
+    })
+    await expect(openNativePath('/tmp/missing.txt', signal(), { platform: 'darwin' })).rejects.toMatchObject({
+      message: 'open failed', cause: commandError, code: 1,
+      stdout: 'partial output', stderr: 'failure details',
+    })
   })
 })