diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index 9c0ee568c74..1b695fe071a 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -53,7 +53,7 @@ allowBuilds:
   node-pty: true
   sherpa-onnx: true
   ssh2: false
-  "@orca/windows-registry": false
+  '@orca/windows-registry': false
 
 overrides:
   monaco-editor>dompurify: 3.4.14
diff --git a/src/main/runtime/runtime-client-settings-terminal-copy-projection.test.ts b/src/main/runtime/runtime-client-settings-terminal-copy-projection.test.ts
new file mode 100644
index 00000000000..8a6fad5065c
--- /dev/null
+++ b/src/main/runtime/runtime-client-settings-terminal-copy-projection.test.ts
@@ -0,0 +1,37 @@
+import { describe, expect, it } from 'vitest'
+import { RuntimeClientSettingsController } from './runtime-client-settings'
+import { createGlobalSettingsFixture } from '../../shared/global-settings-test-fixture'
+import type { GlobalSettings } from '../../shared/global-settings-types'
+
+// Why: `settings.get` is an explicit allowlist, not the whole settings object.
+// Mobile's terminal Copy reads terminalCopyTrimsGutter from it (#19770), and a
+// field missing here is indistinguishable on the client from an older host —
+// so the opt-out would silently never arrive.
+function projectionOf(settings: Partial<GlobalSettings>) {
+  // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: get() reads nothing but store.getSettings(); every other RuntimeStore member is unreachable from that path.
+  return new RuntimeClientSettingsController({ getSettings: () => settings } as never).get()
+}
+
+function hostSettings(overrides: Partial<GlobalSettings>): Partial<GlobalSettings> {
+  return { ...createGlobalSettingsFixture({ workspaceDir: '/w' }), ...overrides }
+}
+
+describe('RuntimeClientSettingsController terminal copy projection', () => {
+  it('publishes the gutter-trim opt-out to paired clients', () => {
+    expect(
+      projectionOf(hostSettings({ terminalCopyTrimsGutter: false })).terminalCopyTrimsGutter
+    ).toBe(false)
+  })
+
+  it('publishes the gutter-trim opt-in to paired clients', () => {
+    expect(
+      projectionOf(hostSettings({ terminalCopyTrimsGutter: true })).terminalCopyTrimsGutter
+    ).toBe(true)
+  })
+
+  it('reports on when the host has no persisted preference', () => {
+    const settings = hostSettings({})
+    delete settings.terminalCopyTrimsGutter
+    expect(projectionOf(settings).terminalCopyTrimsGutter).toBe(true)
+  })
+})
diff --git a/src/main/runtime/runtime-client-settings.ts b/src/main/runtime/runtime-client-settings.ts
index 900900700f3..4e36ee22024 100644
--- a/src/main/runtime/runtime-client-settings.ts
+++ b/src/main/runtime/runtime-client-settings.ts
@@ -27,6 +27,7 @@ export type RuntimeClientSettings = Pick<
   | 'agentDefaultArgs'
   | 'agentDefaultEnv'
   | 'agentStatusHooksEnabled'
+  | 'terminalCopyTrimsGutter'
   | 'defaultTaskSource'
   | 'defaultTaskViewPreset'
   | 'visibleTaskProviders'
@@ -97,6 +98,9 @@ export class RuntimeClientSettingsController {
       agentDefaultArgs: settings.agentDefaultArgs ?? {},
       agentDefaultEnv: settings.agentDefaultEnv ?? {},
       agentStatusHooksEnabled: settings.agentStatusHooksEnabled !== false,
+      // Why projected: mobile's terminal Copy honours this, and a host predating
+      // the setting sends no key, which the client reads as on (#19770).
+      terminalCopyTrimsGutter: settings.terminalCopyTrimsGutter !== false,
       defaultTaskSource: settings.defaultTaskSource ?? 'github',
       defaultTaskViewPreset: settings.defaultTaskViewPreset ?? 'issues',
       visibleTaskProviders: settings.visibleTaskProviders ?? [...TASK_PROVIDERS],
diff --git a/src/main/runtime/runtime-store-contract.ts b/src/main/runtime/runtime-store-contract.ts
index f3f5d5a8f51..b1471ff8efe 100644
--- a/src/main/runtime/runtime-store-contract.ts
+++ b/src/main/runtime/runtime-store-contract.ts
@@ -87,6 +87,7 @@ export type RuntimeStore = {
     terminalWindowsShell?: GlobalSettings['terminalWindowsShell']
     floatingTerminalEnabled?: GlobalSettings['floatingTerminalEnabled']
     agentStatusHooksEnabled?: GlobalSettings['agentStatusHooksEnabled']
+    terminalCopyTrimsGutter?: GlobalSettings['terminalCopyTrimsGutter']
     experimentalNativeChat?: GlobalSettings['experimentalNativeChat']
     openAgentTabsInChatByDefault?: GlobalSettings['openAgentTabsInChatByDefault']
     experimentalStructuredNativeChat?: GlobalSettings['experimentalStructuredNativeChat']
diff --git a/src/shared/source-scan/source-tree-walk.test.ts b/src/shared/source-scan/source-tree-walk.test.ts
index afc7c8dba88..4030fa2f37c 100644
--- a/src/shared/source-scan/source-tree-walk.test.ts
+++ b/src/shared/source-scan/source-tree-walk.test.ts
@@ -108,7 +108,6 @@ describe('scanSourceTree filesystem traversal', () => {
     expect(statSync).toHaveBeenCalledExactlyOnceWith(join(root, 'alias'))
   })
 
-
   it('still reports a broken link instead of silently dropping it', () => {
     const target = join(root, '.target')
     mkdirSync(target)
diff --git a/src/shared/terminal-selection-gutter.ts b/src/shared/terminal-selection-gutter.ts
index 30650ebb4e5..ad30ce0a839 100644
--- a/src/shared/terminal-selection-gutter.ts
+++ b/src/shared/terminal-selection-gutter.ts
@@ -8,8 +8,11 @@
 // selection that starts mid-line, or that covers any column-0 line, shares a
 // run of zero and comes back untouched.
 
-// Terminal cells never hold tabs (the emulator expands them) and xterm folds
-// non-breaking spaces into plain ones, so spaces are the whole alphabet here.
+// Spaces are the whole alphabet here: terminal cells never hold tabs (the
+// emulator expands them), and xterm's selectionText getter already folds every
+// NBSP cell to a plain space on its way out (SelectionService.ts, the
+// ALL_NON_BREAKING_SPACE_REGEX replace) — that is the selection path, not the
+// input path.
 const LEADING_SPACES = /^ */
 
 type SelectionLine = { indent: number; text: string; terminator: string }