diff --git a/src/main/acp/acp-agent-connection.ts b/src/main/acp/acp-agent-connection.ts
index 8bca757219d..0c7ede25b1c 100644
--- a/src/main/acp/acp-agent-connection.ts
+++ b/src/main/acp/acp-agent-connection.ts
@@ -6,7 +6,7 @@ import {
   type ProviderProcessExit
 } from '../provider-process/managed-provider-process'
 import type { ProviderProcessLaunch } from '../provider-process/provider-process-launch'
-import { AcpAuthRequiredError, AcpConnectionClosedError } from './acp-errors'
+import { AcpConnectionClosedError, AcpSignInPromptError } from './acp-errors'
 import { resolveAcpPeerOptions, type AcpPeerOptions } from './acp-peer-limits'
 import { AcpSessionRuntime, type AcpSessionRuntimeOptions } from './acp-session-runtime'
 
@@ -135,7 +135,7 @@ export class AcpAgentConnection extends AcpSessionRuntime {
     child.on('error', (error) => super.close(error))
     signedOut = () => {
       signIn?.answered?.(false)
-      super.close(new AcpAuthRequiredError('The agent asked to sign in in a browser'))
+      super.close(new AcpSignInPromptError('The agent asked to sign in in a browser'))
     }
     // A broken sign-in line on the protocol stream is a broken agent, not a sign-in answer.
     unreadable = () =>
diff --git a/src/main/acp/acp-errors.ts b/src/main/acp/acp-errors.ts
index edcc93de077..9918b8ad3b7 100644
--- a/src/main/acp/acp-errors.ts
+++ b/src/main/acp/acp-errors.ts
@@ -31,6 +31,20 @@ export class AcpAuthRequiredError extends AcpAgentError {
   }
 }
 
+/** The agent printed its sign-in prompt instead of answering, so the message is Orca's, not its. */
+export class AcpSignInPromptError extends AcpAuthRequiredError {}
+
+/** Types an agent's sign-in answer. A sign-in prompt close stays itself: a copy would pass Orca's
+ *  log words off as the agent's. */
+export function acpAuthRequiredError(
+  error: AcpAgentError,
+  authMethods?: AuthMethod[]
+): AcpAuthRequiredError {
+  return error instanceof AcpSignInPromptError
+    ? error
+    : new AcpAuthRequiredError(error.message, error.data, authMethods)
+}
+
 /** Orca could not read the agent's answer; `data` keeps the raw answer, `issues` why it failed. */
 export class AcpInvalidResponseError extends AcpRpcError {
   constructor(
diff --git a/src/main/acp/acp-response-settlement.ts b/src/main/acp/acp-response-settlement.ts
index e0f2c340b40..2039403b63d 100644
--- a/src/main/acp/acp-response-settlement.ts
+++ b/src/main/acp/acp-response-settlement.ts
@@ -1,5 +1,5 @@
 import type { z } from 'zod'
-import { AcpAgentError, AcpAuthRequiredError, AcpInvalidResponseError } from './acp-errors'
+import { AcpAgentError, AcpInvalidResponseError, acpAuthRequiredError } from './acp-errors'
 import type { AcpJsonRpcPeer } from './acp-json-rpc-peer'
 
 export function callAcpSession<T>(
@@ -16,7 +16,7 @@ export function callAcpSession<T>(
         const error = response.error
         if (error instanceof AcpAgentError && error.code === -32000) {
           answered?.(false)
-          throw new AcpAuthRequiredError(error.message, error.data)
+          throw acpAuthRequiredError(error)
         }
         throw error
       }
diff --git a/src/main/acp/acp-session-setup.ts b/src/main/acp/acp-session-setup.ts
index 8296315eb26..0bbcf16b354 100644
--- a/src/main/acp/acp-session-setup.ts
+++ b/src/main/acp/acp-session-setup.ts
@@ -1,5 +1,5 @@
 import type { z } from 'zod'
-import { AcpAuthRequiredError, AcpRpcError } from './acp-errors'
+import { AcpAuthRequiredError, AcpRpcError, acpAuthRequiredError } from './acp-errors'
 import {
   NewSessionResponseSchema,
   LoadSessionResponseSchema,
@@ -67,7 +67,7 @@ export async function setupAcpSession(
     if (!(error instanceof AcpAuthRequiredError)) {
       throw error
     }
-    const required = new AcpAuthRequiredError(error.message, error.data, initialized.authMethods)
+    const required = acpAuthRequiredError(error, initialized.authMethods)
     const method = initialized.authMethods?.find((method) => method.id === options.authMethodId)
     if (!method) {
       throw required
@@ -77,7 +77,7 @@ export async function setupAcpSession(
       return await setup()
     } catch (failure) {
       if (failure instanceof AcpAuthRequiredError) {
-        throw new AcpAuthRequiredError(failure.message, failure.data, initialized.authMethods)
+        throw acpAuthRequiredError(failure, initialized.authMethods)
       }
       throw failure
     }
diff --git a/src/main/acp/acp-structured-sign-in.test.ts b/src/main/acp/acp-structured-sign-in.test.ts
index 7f4cea61369..2343ef650de 100644
--- a/src/main/acp/acp-structured-sign-in.test.ts
+++ b/src/main/acp/acp-structured-sign-in.test.ts
@@ -5,7 +5,7 @@ import { providerStartupFailureFact } from '../native-chat/agent-session-wire/st
 import { agentSessionFailureSentence } from '../../shared/agent-session-failure-words'
 import { AgentSessionAcquisitionRefusal } from '../native-chat/agent-session-wire/structured-agent-session-adapter'
 import { closeProviderTimelineRigs } from '../native-chat/agent-session-timeline/provider-timeline-assembler-test-support'
-import { AcpAuthRequiredError } from './acp-errors'
+import { AcpSignInPromptError } from './acp-errors'
 import { ACP_LAUNCH_SPECS } from './acp-launch-specs'
 import { AcpSessionRuntime } from './acp-session-runtime'
 import {
@@ -84,7 +84,8 @@ it('ends a running turn signed out when the connection closes for sign-in', asyn
   await sendHello(rig, 'first')
   await rig.frame('session/prompt')
   // The protocol close the real connection makes at a sign-in prompt line on stderr.
-  AcpSessionRuntime.prototype.close.call(rig.child(), new AcpAuthRequiredError('Sign in'))
+  const internal = 'The agent asked to sign in in a browser'
+  AcpSessionRuntime.prototype.close.call(rig.child(), new AcpSignInPromptError(internal))
   await rig.settle()
   expect(rig.settled).toContainEqual(
     expect.objectContaining({
@@ -93,6 +94,21 @@ it('ends a running turn signed out when the connection closes for sign-in', asyn
       rejection: expect.objectContaining({ kind: 'notSignedIn' })
     })
   )
+  // Orca's own words for the prompt are for logs; the chat says only how to sign in.
+  const rejected = rig.settled.find((item) => 'state' in item && item.state === 'rejected')
+  expect(rejected && 'reason' in rejected ? rejected.reason : '').not.toContain(internal)
+})
+
+it('starts signed out without Orca words when the connection closes for sign-in', async () => {
+  const rig = await openAcpAdapterRig({ script: (agent) => agent.on('session/new', () => {}) })
+  const acquired = rig.acquire().catch((failure: unknown) => failure)
+  await rig.frame('session/new')
+  const internal = 'The agent asked to sign in in a browser'
+  AcpSessionRuntime.prototype.close.call(rig.child(), new AcpSignInPromptError(internal))
+  const error = await acquired
+  // Session setup re-types sign-in answers; this close must stay Orca's, words and all.
+  expect(error).toMatchObject({ reason: 'notSignedIn' })
+  expect(providerDiagnosticOf(error)).toBeUndefined()
 })
 
 it.each(ACP_LAUNCH_SPECS)(
diff --git a/src/main/acp/acp-turn-failures.ts b/src/main/acp/acp-turn-failures.ts
index ba87ec6a505..920937abd2a 100644
--- a/src/main/acp/acp-turn-failures.ts
+++ b/src/main/acp/acp-turn-failures.ts
@@ -7,7 +7,7 @@ import { agentSessionFailureWords } from '../../shared/agent-session-failure-wor
 import { BoundedMap } from '../../shared/bounded-map'
 import type { ProviderTimelineEvent } from '../native-chat/agent-session-timeline/provider-timeline-event'
 import type { AcpDialect } from './acp-dialects/acp-dialect'
-import { AcpAgentError, AcpAuthRequiredError } from './acp-errors'
+import { AcpAgentError, AcpAuthRequiredError, AcpSignInPromptError } from './acp-errors'
 import { AgentSessionAcquisitionRefusal } from '../native-chat/agent-session-wire/structured-agent-session-adapter'
 
 /** Ends the provider failed, rather than ones it chose (a refusal, a token limit). */
@@ -20,6 +20,10 @@ function acpStopReasonFailed(stopReason: string): boolean {
 /** The provider's words in its error answer to `session/prompt`. Agents often answer a generic
  *  message ("Internal error") and keep their own words in `data`. */
 export function acpPromptErrorDetail(dialect: AcpDialect, error: AcpAgentError): string {
+  // Empty: the sign-in sentence alone says what to do.
+  if (error instanceof AcpSignInPromptError) {
+    return ''
+  }
   return dialect.promptErrorDetail?.(error) ?? acpErrorDataWords(error.data) ?? error.message
 }
 
diff --git a/src/renderer/src/components/managed-runtime/ManagedRuntimeActionsMenu.tsx b/src/renderer/src/components/managed-runtime/ManagedRuntimeActionsMenu.tsx
new file mode 100644
index 00000000000..43e4afbe804
--- /dev/null
+++ b/src/renderer/src/components/managed-runtime/ManagedRuntimeActionsMenu.tsx
@@ -0,0 +1,70 @@
+import { useState } from 'react'
+import { MoreHorizontal } from 'lucide-react'
+import { translate } from '@/i18n/i18n'
+import type { RuntimeClientTarget } from '../../../../shared/runtime-client-target'
+import { Button } from '../ui/button'
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger
+} from '../ui/dropdown-menu'
+import { ManagedRuntimeRemoveDialog } from './ManagedRuntimeRemoveDialog'
+
+/** The ⋯ menu beside an installed runtime's switch: Update or Reinstall, and Remove behind a
+ *  confirmation. */
+export function ManagedRuntimeActionsMenu(props: {
+  agentLabel: string
+  host: RuntimeClientTarget
+  /** Update or Reinstall, when the host offers one. */
+  install: { label: string; onSelect: () => void } | null
+  onRemove: (() => void) | null
+  disabled: boolean
+}): React.JSX.Element {
+  const { agentLabel, install, onRemove, disabled } = props
+  const [confirming, setConfirming] = useState(false)
+  return (
+    <>
+      <DropdownMenu>
+        <DropdownMenuTrigger asChild>
+          <Button
+            variant="ghost"
+            size="icon-xs"
+            aria-label={translate(
+              'components.managed-runtime.moreActions',
+              'More actions for {{agent}}',
+              { agent: agentLabel }
+            )}
+          >
+            <MoreHorizontal />
+          </Button>
+        </DropdownMenuTrigger>
+        <DropdownMenuContent align="end">
+          {install === null ? null : (
+            <DropdownMenuItem disabled={disabled} onSelect={install.onSelect}>
+              {install.label}
+            </DropdownMenuItem>
+          )}
+          {onRemove === null ? null : (
+            <DropdownMenuItem
+              variant="destructive"
+              disabled={disabled}
+              onSelect={() => setConfirming(true)}
+            >
+              {translate('components.managed-runtime.remove', 'Remove downloaded runtime')}
+            </DropdownMenuItem>
+          )}
+        </DropdownMenuContent>
+      </DropdownMenu>
+      {onRemove === null ? null : (
+        <ManagedRuntimeRemoveDialog
+          agentLabel={agentLabel}
+          host={props.host}
+          open={confirming}
+          onOpenChange={setConfirming}
+          onRemove={onRemove}
+        />
+      )}
+    </>
+  )
+}
diff --git a/src/renderer/src/components/managed-runtime/ManagedRuntimeInstallRow.tsx b/src/renderer/src/components/managed-runtime/ManagedRuntimeInstallRow.tsx
index 564d3acf538..5ffda552d14 100644
--- a/src/renderer/src/components/managed-runtime/ManagedRuntimeInstallRow.tsx
+++ b/src/renderer/src/components/managed-runtime/ManagedRuntimeInstallRow.tsx
@@ -13,19 +13,22 @@ import {
   managedRuntimeInstallView,
   type ManagedRuntimeInstallAction
 } from './managed-runtime-install-view'
+import { ManagedRuntimeActionsMenu } from './ManagedRuntimeActionsMenu'
 import { ManagedRuntimeLinkButton } from './ManagedRuntimeLinkButton'
-import { ManagedRuntimeRemoveButton } from './ManagedRuntimeRemoveButton'
 
 // Parts are joined by ' · ', so a sentence followed by another part drops its full stop.
 const said = (text: string, last: boolean): string => (last ? text : text.replace(/[.。]$/u, ''))
 
-/** Settings' one-line install state for the runtime Orca provides an agent, on the host it runs on,
- *  with its actions as links, except a first Install, which is a button the caller places at its
- *  row's end. A chat's install card shows the same host answer, so either one's action moves both. */
+/** Settings' one-line install state for the runtime Orca provides an agent, on the host it runs
+ *  on, with Cancel and retries as links. A first Install button, and the ⋯ menu with Update,
+ *  Reinstall and Remove, are what the caller places at its row's end. A chat's install card shows
+ *  the same host answer, so either one's action moves both. */
 export function ManagedRuntimeInstallRow(props: {
   observation: Extract<ManagedRuntimeInstallObservation, { kind: 'active' }>
   agentLabel: string
-  children: (line: React.ReactNode, button: React.ReactNode) => React.ReactNode
+  children: (line: React.ReactNode, actions: React.ReactNode) => React.ReactNode
+  /** A sign-in runs the installed server, so Install and Remove wait for it; Cancel does not. */
+  signInRunning?: boolean
 }): React.JSX.Element {
   const { observation, agentLabel } = props
   // A click holds its button until the host answers, so a double click starts nothing twice.
@@ -55,12 +58,13 @@ export function ManagedRuntimeInstallRow(props: {
   const button = view.prominent ? view.action : null
   const action = button ? null : view.action
   const removable = observation.removable && view.removable
+  const held = pending !== null || props.signInRunning === true
   const primary = (chosen: ManagedRuntimeInstallAction) => () =>
     chosen.kind === 'cancel'
       ? cancelManagedRuntimeInstall(subject, chosen.operationId)
       : installManagedRuntime(subject)
   const parts: React.ReactNode[] = []
-  const trailing = Boolean(alert || action || removable || view.note)
+  const trailing = Boolean(alert || action || view.note)
   if (view.status !== null) {
     parts.push(
       <span key="status" className="inline-flex items-center gap-1.5">
@@ -81,7 +85,7 @@ export function ManagedRuntimeInstallRow(props: {
   if (alert) {
     parts.push(
       <span key="alert" role="alert" className="break-words text-destructive">
-        {said(alert, !(action || removable || view.note))}
+        {said(alert, !(action || view.note))}
       </span>
     )
   }
@@ -89,24 +93,13 @@ export function ManagedRuntimeInstallRow(props: {
     parts.push(
       <ManagedRuntimeLinkButton
         key="action"
-        disabled={pending !== null}
+        disabled={action.kind === 'cancel' ? pending !== null : held}
         onClick={() => act(action.kind, primary(action))}
       >
         {action.label}
       </ManagedRuntimeLinkButton>
     )
   }
-  if (removable) {
-    parts.push(
-      <ManagedRuntimeRemoveButton
-        key="remove"
-        agentLabel={agentLabel}
-        host={subject.target}
-        disabled={pending !== null}
-        onRemove={() => act('remove', () => removeManagedRuntime(subject))}
-      />
-    )
-  }
   if (view.note) {
     parts.push(<span key="note">{view.note}</span>)
   }
@@ -122,19 +115,33 @@ export function ManagedRuntimeInstallRow(props: {
       )}
     </div>
   )
+  const menu = view.menuAction
+  const install = menu && { label: menu.label, onSelect: () => act(menu.kind, primary(menu)) }
+  const remove = removable ? () => act('remove', () => removeManagedRuntime(subject)) : null
   return (
     <>
       {props.children(
         line,
-        button ? (
-          <Button
-            size="xs"
-            disabled={pending !== null}
-            onClick={() => act(button.kind, primary(button))}
-          >
-            {button.label}
-          </Button>
-        ) : null
+        <>
+          {button ? (
+            <Button
+              size="xs"
+              disabled={button.kind === 'cancel' ? pending !== null : held}
+              onClick={() => act(button.kind, primary(button))}
+            >
+              {button.label}
+            </Button>
+          ) : null}
+          {install || remove ? (
+            <ManagedRuntimeActionsMenu
+              agentLabel={agentLabel}
+              host={subject.target}
+              install={install}
+              onRemove={remove}
+              disabled={held}
+            />
+          ) : null}
+        </>
       )}
     </>
   )
diff --git a/src/renderer/src/components/managed-runtime/ManagedRuntimeRemoveButton.tsx b/src/renderer/src/components/managed-runtime/ManagedRuntimeRemoveButton.tsx
deleted file mode 100644
index 904b7a33a35..00000000000
--- a/src/renderer/src/components/managed-runtime/ManagedRuntimeRemoveButton.tsx
+++ /dev/null
@@ -1,78 +0,0 @@
-import { useState } from 'react'
-import { translate } from '@/i18n/i18n'
-import { selectExecutionHostDisplayLabel } from '@/lib/execution-host-display-label'
-import { useAppStore } from '@/store'
-import { toRuntimeExecutionHostId } from '../../../../shared/execution-host'
-import type { RuntimeClientTarget } from '../../../../shared/runtime-client-target'
-import { Button } from '../ui/button'
-import {
-  Dialog,
-  DialogContent,
-  DialogDescription,
-  DialogFooter,
-  DialogHeader,
-  DialogTitle
-} from '../ui/dialog'
-import { ManagedRuntimeLinkButton } from './ManagedRuntimeLinkButton'
-
-/** Settings' Remove link for the runtime Orca downloaded, behind a confirmation: it stops running
- *  chats. */
-export function ManagedRuntimeRemoveButton(props: {
-  agentLabel: string
-  host: RuntimeClientTarget
-  disabled: boolean
-  onRemove: () => void
-}): React.JSX.Element {
-  const { agentLabel, host, disabled, onRemove } = props
-  const [confirming, setConfirming] = useState(false)
-  const hostLabel = useAppStore((state) =>
-    host.kind === 'environment'
-      ? selectExecutionHostDisplayLabel(state, toRuntimeExecutionHostId(host.environmentId))
-      : translate('components.managed-runtime.thisComputer', 'this computer')
-  )
-  return (
-    <>
-      <ManagedRuntimeLinkButton
-        disabled={disabled}
-        aria-label={translate('components.managed-runtime.remove', 'Remove downloaded runtime')}
-        onClick={() => setConfirming(true)}
-      >
-        {translate('components.managed-runtime.removeConfirm', 'Remove')}
-      </ManagedRuntimeLinkButton>
-      <Dialog open={confirming} onOpenChange={setConfirming}>
-        <DialogContent>
-          <DialogHeader>
-            <DialogTitle>
-              {translate(
-                'components.managed-runtime.removeTitle',
-                'Remove the downloaded {{agent}} runtime from {{host}}?',
-                { agent: agentLabel, host: hostLabel }
-              )}
-            </DialogTitle>
-            <DialogDescription>
-              {translate(
-                'components.managed-runtime.removeDescription',
-                '{{agent}} chats that are running stop. Their history is kept.',
-                { agent: agentLabel }
-              )}
-            </DialogDescription>
-          </DialogHeader>
-          <DialogFooter>
-            <Button variant="outline" onClick={() => setConfirming(false)}>
-              {translate('components.managed-runtime.removeKeep', 'Cancel')}
-            </Button>
-            <Button
-              variant="destructive"
-              onClick={() => {
-                setConfirming(false)
-                onRemove()
-              }}
-            >
-              {translate('components.managed-runtime.removeConfirm', 'Remove')}
-            </Button>
-          </DialogFooter>
-        </DialogContent>
-      </Dialog>
-    </>
-  )
-}
diff --git a/src/renderer/src/components/managed-runtime/ManagedRuntimeRemoveDialog.tsx b/src/renderer/src/components/managed-runtime/ManagedRuntimeRemoveDialog.tsx
new file mode 100644
index 00000000000..f792ef249de
--- /dev/null
+++ b/src/renderer/src/components/managed-runtime/ManagedRuntimeRemoveDialog.tsx
@@ -0,0 +1,66 @@
+import { translate } from '@/i18n/i18n'
+import { selectExecutionHostDisplayLabel } from '@/lib/execution-host-display-label'
+import { useAppStore } from '@/store'
+import { toRuntimeExecutionHostId } from '../../../../shared/execution-host'
+import type { RuntimeClientTarget } from '../../../../shared/runtime-client-target'
+import { Button } from '../ui/button'
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle
+} from '../ui/dialog'
+
+/** Confirms removing the runtime Orca downloaded: it stops running chats. */
+export function ManagedRuntimeRemoveDialog(props: {
+  agentLabel: string
+  host: RuntimeClientTarget
+  open: boolean
+  onOpenChange: (open: boolean) => void
+  onRemove: () => void
+}): React.JSX.Element {
+  const { agentLabel, host, open, onOpenChange, onRemove } = props
+  const hostLabel = useAppStore((state) =>
+    host.kind === 'environment'
+      ? selectExecutionHostDisplayLabel(state, toRuntimeExecutionHostId(host.environmentId))
+      : translate('components.managed-runtime.thisComputer', 'this computer')
+  )
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent>
+        <DialogHeader>
+          <DialogTitle>
+            {translate(
+              'components.managed-runtime.removeTitle',
+              'Remove the downloaded {{agent}} runtime from {{host}}?',
+              { agent: agentLabel, host: hostLabel }
+            )}
+          </DialogTitle>
+          <DialogDescription>
+            {translate(
+              'components.managed-runtime.removeDescription',
+              '{{agent}} chats that are running stop. Their history is kept.',
+              { agent: agentLabel }
+            )}
+          </DialogDescription>
+        </DialogHeader>
+        <DialogFooter>
+          <Button variant="outline" onClick={() => onOpenChange(false)}>
+            {translate('components.managed-runtime.removeKeep', 'Cancel')}
+          </Button>
+          <Button
+            variant="destructive"
+            onClick={() => {
+              onOpenChange(false)
+              onRemove()
+            }}
+          >
+            {translate('components.managed-runtime.removeConfirm', 'Remove')}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  )
+}
diff --git a/src/renderer/src/components/managed-runtime/managed-runtime-install-view.test.ts b/src/renderer/src/components/managed-runtime/managed-runtime-install-view.test.ts
index 11398c6605f..fdd18df4568 100644
--- a/src/renderer/src/components/managed-runtime/managed-runtime-install-view.test.ts
+++ b/src/renderer/src/components/managed-runtime/managed-runtime-install-view.test.ts
@@ -25,8 +25,11 @@ const op = (patch: Partial<ManagedRuntimeOperation>): ManagedRuntimeOperation =>
   ...patch
 })
 
+const viewOf = (patch: Partial<ManagedRuntimeInstallState>) =>
+  managedRuntimeInstallView({ kind: 'known', state: { ...idle, ...patch } }, 'Fake')
+
 function shown(patch: Partial<ManagedRuntimeInstallState>) {
-  const view = managedRuntimeInstallView({ kind: 'known', state: { ...idle, ...patch } }, 'Fake')
+  const view = viewOf(patch)
   return [view.status, view.action?.label ?? null, view.error, view.note]
 }
 
@@ -77,14 +80,18 @@ describe('managedRuntimeInstallView', () => {
       'No space left.',
       null
     ])
-    // A healthy copy offers no Reinstall; Remove is its only action.
-    expect(shown(installed)).toEqual(['Installed.', null, null, null])
-    expect(shown({ ...installed, installedVersion: '1.2.0', installedCurrent: false })).toEqual([
-      'Installed.',
-      'Update',
-      null,
-      null
-    ])
+    // An installed copy's line says only that; Reinstall or Update and Remove sit in its menu.
+    expect(shown(installed)).toEqual(['Installed', null, null, null])
+    expect(viewOf({ ...installed, canRemove: true })).toMatchObject({
+      removable: true,
+      menuAction: { kind: 'install', label: 'Reinstall Fake' }
+    })
+    const update = viewOf({ ...installed, installedVersion: '1.2.0', installedCurrent: false })
+    expect(update).toMatchObject({
+      status: 'Installed',
+      action: null,
+      menuAction: { label: 'Update' }
+    })
     const removal = (patch: Partial<ManagedRuntimeOperation>) =>
       managedRuntimeInstallView(
         {
@@ -106,7 +113,7 @@ describe('managedRuntimeInstallView', () => {
     })
     // A refused removal keeps the files, so Remove stays offered beside the host's reason.
     expect(removal({ phase: 'failed', error: 'Fake could not be stopped.' })).toMatchObject({
-      status: 'Installed.',
+      status: 'Installed',
       error: 'Fake could not be stopped.',
       removable: true
     })
@@ -119,12 +126,12 @@ describe('managedRuntimeInstallView', () => {
       null,
       null
     ])
-    expect(shown({ damaged: true })).toEqual([
-      'This copy of Fake is damaged.',
-      'Reinstall',
-      null,
-      null
-    ])
+    expect(viewOf({ damaged: true })).toMatchObject({
+      status: 'This copy of Fake is damaged.',
+      action: { label: 'Reinstall' },
+      prominent: true,
+      menuAction: null
+    })
     const external = { source: 'external' as const }
     expect(shown(external)).toEqual([
       'Uses the copy of Fake found on this host.',
diff --git a/src/renderer/src/components/managed-runtime/managed-runtime-install-view.ts b/src/renderer/src/components/managed-runtime/managed-runtime-install-view.ts
index 1dfe753fedc..5948cdebb60 100644
--- a/src/renderer/src/components/managed-runtime/managed-runtime-install-view.ts
+++ b/src/renderer/src/components/managed-runtime/managed-runtime-install-view.ts
@@ -13,6 +13,8 @@ export type ManagedRuntimeInstallView = {
   /** Why the last operation or status read failed. */
   error: string | null
   action: ManagedRuntimeInstallAction | null
+  /** Update or Reinstall for a copy on disk, offered in the row's menu beside Remove. */
+  menuAction: ManagedRuntimeInstallAction | null
   /** The action is the first step to using the agent, so Settings draws it as a button. */
   prominent: boolean
   /** Settings may offer to delete the copy Orca installed: one is there and nothing runs. */
@@ -30,6 +32,7 @@ const EMPTY: ManagedRuntimeInstallView = {
   progress: null,
   error: null,
   action: null,
+  menuAction: null,
   prominent: false,
   removable: false,
   removing: false,
@@ -87,12 +90,14 @@ function settledView(state: ManagedRuntimeInstallState, agent: string): ManagedR
   const view = (
     status: string | null,
     label: string | null,
-    note: string | null = null
+    note: string | null = null,
+    menuLabel: string | null = null
   ): ManagedRuntimeInstallView => ({
     ...EMPTY,
     status,
     error,
     action: label === null ? null : { kind: 'install', label },
+    menuAction: menuLabel === null ? null : { kind: 'install', label: menuLabel },
     removable: state.canRemove === true,
     note
   })
@@ -111,11 +116,16 @@ function settledView(state: ManagedRuntimeInstallState, agent: string): ManagedR
     )
   }
   if (state.installedVersion !== null) {
-    // A healthy current copy needs nothing; Remove is its only action.
-    const label = state.installedCurrent
-      ? null
-      : translate('components.managed-runtime.update', 'Update')
-    return view(translate('components.managed-runtime.installed', 'Installed.'), label)
+    const reinstall = translate('components.managed-runtime.reinstall', 'Reinstall {{agent}}', {
+      agent
+    })
+    // Reinstalling a current copy checks it and repairs what's missing, so it needs the pin.
+    const label = !state.installedCurrent
+      ? translate('components.managed-runtime.update', 'Update')
+      : state.available
+        ? reinstall
+        : null
+    return view(translate('components.managed-runtime.installed', 'Installed'), null, null, label)
   }
   if (!state.available) {
     return view(
@@ -128,12 +138,14 @@ function settledView(state: ManagedRuntimeInstallState, agent: string): ManagedR
     )
   }
   if (state.damaged) {
-    return view(
-      translate('components.managed-runtime.damaged', 'This copy of {{agent}} is damaged.', {
-        agent
-      }),
-      translate('components.managed-runtime.reinstall', 'Reinstall')
+    const status = translate(
+      'components.managed-runtime.damaged',
+      'This copy of {{agent}} is damaged.',
+      { agent }
     )
+    // The repair is the next step, so it is the row's button rather than a menu item.
+    const label = translate('components.managed-runtime.reinstallShort', 'Reinstall')
+    return { ...view(status, label), prominent: true }
   }
   const retry = translate('components.managed-runtime.tryAgain', 'Try again')
   if (operation?.kind === 'install' && operation.phase === 'cancelled') {
diff --git a/src/renderer/src/components/native-chat/agent-session-availability-words-text.ts b/src/renderer/src/components/native-chat/agent-session-availability-words-text.ts
index 3e6250afda6..a5c8587e44d 100644
--- a/src/renderer/src/components/native-chat/agent-session-availability-words-text.ts
+++ b/src/renderer/src/components/native-chat/agent-session-availability-words-text.ts
@@ -13,6 +13,7 @@ type AvailabilityCopyId = Extract<
   | 'claudeManagedNotSignedIn'
   | 'codexSystemNotSignedIn'
   | 'codexManagedNotSignedIn'
+  | 'antigravityNotSignedIn'
   | 'agentCommandNotSignedIn'
   | 'interactiveAgentNotSignedIn'
   | 'agentNotSignedIn'
@@ -69,6 +70,12 @@ export const AVAILABILITY_PIECES: Record<
       COPY.codexManagedNotSignedIn,
       values
     ),
+  antigravityNotSignedIn: (values) =>
+    translate(
+      'components.native-chat.failureWords.antigravityNotSignedIn',
+      COPY.antigravityNotSignedIn,
+      values
+    ),
   cliMissing: (values) =>
     translate('components.native-chat.failureWords.cliMissing', COPY.cliMissing, values),
   codexCliTooOld: (values) =>
diff --git a/src/renderer/src/components/settings/AntigravityAccountsSection.test.tsx b/src/renderer/src/components/settings/AntigravityAccountsSection.test.tsx
index c6596a9732a..2dbb12deb53 100644
--- a/src/renderer/src/components/settings/AntigravityAccountsSection.test.tsx
+++ b/src/renderer/src/components/settings/AntigravityAccountsSection.test.tsx
@@ -10,7 +10,9 @@ import { callRuntimeRpc } from '@/runtime/runtime-rpc-client'
 import type { AntigravityAccountState } from '../../../../shared/antigravity-account-types'
 
 vi.mock('@/runtime/runtime-antigravity-accounts-client', () => ({
-  callAntigravityAccounts: vi.fn()
+  callAntigravityAccounts: vi.fn(),
+  callAntigravityChatSignIn: vi.fn(),
+  subscribeAntigravityChatSignIn: vi.fn()
 }))
 vi.mock('@/runtime/runtime-rpc-client', () => ({ callRuntimeRpc: vi.fn() }))
 vi.mock('@/lib/agent-catalog', () => ({ AgentIcon: () => null }))
diff --git a/src/renderer/src/components/settings/AntigravityAccountsSection.tsx b/src/renderer/src/components/settings/AntigravityAccountsSection.tsx
index ce3c36d5359..37d71c87530 100644
--- a/src/renderer/src/components/settings/AntigravityAccountsSection.tsx
+++ b/src/renderer/src/components/settings/AntigravityAccountsSection.tsx
@@ -15,6 +15,12 @@ import { Button } from '../ui/button'
 import { Badge } from '../ui/badge'
 import { ManagedRuntimeInstallRow } from '../managed-runtime/ManagedRuntimeInstallRow'
 import { useAppStore } from '../../store'
+import { antigravityChatSignInRunning } from '@/runtime/antigravity-chat-sign-in-status'
+import {
+  AntigravityChatSignInRow,
+  antigravityChatSignInBlocked,
+  useAntigravityChatSignIn
+} from './AntigravityChatSignInRow'
 
 export function AntigravityAccountsSection({
   owner,
@@ -48,6 +54,9 @@ export function AntigravityAccountsSection({
   const nativeChat = useAppStore((s) => s.settings?.experimentalNativeChat === true)
   const chats = nativeChat && runtime !== 'wsl'
   const chatRuntime = useManagedRuntimeInstall(owner, 'antigravity', chats)
+  // A remote host's sign-in finishes from the address pasted back into its row.
+  const chatSignIn = chats && chatRuntime.kind === 'active'
+  const signIn = useAntigravityChatSignIn(chatSignIn ? owner : null)
 
   useEffect(() => {
     mounted.current = true
@@ -288,25 +297,37 @@ export function AntigravityAccountsSection({
         )}
       </p>
       {chats && chatRuntime.kind === 'active' ? (
-        <ManagedRuntimeInstallRow
-          observation={chatRuntime}
-          agentLabel={translate('accounts.antigravity.title', 'Antigravity')}
-        >
-          {(line, button) => (
-            <div className="flex items-center justify-between gap-3">
-              <div className="min-w-0 flex-1 space-y-2">
-                <p className="text-xs text-muted-foreground">
-                  {translate(
-                    'settings.chat.providers.antigravityDescription',
-                    'Antigravity chats run a server Orca downloads to this host, separate from the agy CLI.'
-                  )}
-                </p>
-                {line}
+        <div className="space-y-4">
+          <ManagedRuntimeInstallRow
+            observation={chatRuntime}
+            agentLabel={translate('accounts.antigravity.title', 'Antigravity')}
+            signInRunning={antigravityChatSignInRunning(signIn.flow)}
+          >
+            {(line, actions) => (
+              <div className="flex items-center justify-between gap-3">
+                <div className="min-w-0 flex-1 space-y-2">
+                  <p className="text-xs text-muted-foreground">
+                    {translate(
+                      'settings.chat.providers.antigravityDescription',
+                      'Antigravity chats run a server Orca downloads to this host, separate from the agy CLI.'
+                    )}
+                  </p>
+                  {line}
+                </div>
+                {actions}
               </div>
-              {button}
-            </div>
-          )}
-        </ManagedRuntimeInstallRow>
+            )}
+          </ManagedRuntimeInstallRow>
+          <AntigravityChatSignInRow
+            owner={owner}
+            label={label}
+            description={translate(
+              'accounts.antigravity.chatDescription',
+              'Chats use their own Antigravity sign-in, separate from your agy account above. Sign in once on this device.'
+            )}
+            disabled={antigravityChatSignInBlocked(chatRuntime)}
+          />
+        </div>
       ) : null}
     </section>
   )
diff --git a/src/renderer/src/components/settings/AntigravityChatSignInRow.test.tsx b/src/renderer/src/components/settings/AntigravityChatSignInRow.test.tsx
new file mode 100644
index 00000000000..8d4393bb8c0
--- /dev/null
+++ b/src/renderer/src/components/settings/AntigravityChatSignInRow.test.tsx
@@ -0,0 +1,159 @@
+// @vitest-environment happy-dom
+import { act, cleanup, render, screen } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { afterEach, expect, it, vi } from 'vitest'
+import type {
+  AntigravityChatAuth,
+  AntigravityChatSignInState
+} from '../../../../shared/antigravity-account-types'
+import type { RuntimeClientTarget } from '../../../../shared/runtime-client-target'
+import { callAntigravityChatSignIn } from '@/runtime/runtime-antigravity-accounts-client'
+import { AntigravityChatSignInRow } from './AntigravityChatSignInRow'
+import { TooltipProvider } from '../ui/tooltip'
+
+const url = 'https://accounts.google.com/o/oauth2/v2/auth?state=s'
+type FakeHost = {
+  revision: number
+  auth: AntigravityChatAuth
+  flow: AntigravityChatSignInState | null
+  streams: Set<(status: unknown) => void>
+}
+// Each host's own sign-in status, pushed to its subscribers by revision as the host does.
+const fake = vi.hoisted(() => {
+  const hosts = new Map<string, FakeHost>()
+  const hostOf = (owner: RuntimeClientTarget): FakeHost => {
+    const key = owner.kind === 'local' ? '' : owner.environmentId
+    let host = hosts.get(key)
+    if (!host) {
+      host = { revision: 0, auth: 'unknown', flow: null, streams: new Set() }
+      hosts.set(key, host)
+    }
+    return host
+  }
+  const status = (host: FakeHost) => ({
+    revision: host.revision,
+    auth: host.auth,
+    flow: host.flow
+  })
+  const publish = (
+    owner: RuntimeClientTarget,
+    flow: AntigravityChatSignInState | null,
+    auth: AntigravityChatAuth = 'unknown'
+  ) => {
+    const host = hostOf(owner)
+    Object.assign(host, { revision: host.revision + 1, flow, auth })
+    host.streams.forEach((emit) => emit(status(host)))
+  }
+  const api: {
+    hostOf: typeof hostOf
+    status: typeof status
+    publish: typeof publish
+    start: Promise<{ flowId: string }> | null
+  } = { hostOf, status, publish, start: null }
+  return api
+})
+const { publish } = fake
+vi.mock('@/runtime/runtime-antigravity-accounts-client', () => ({
+  callAntigravityChatSignIn: vi.fn(async (owner: RuntimeClientTarget, action: string) => {
+    if (action === 'Start') {
+      if (fake.start) {
+        return fake.start
+      }
+      fake.publish(owner, { flowId: 'f', phase: 'starting' })
+      return { flowId: 'f' }
+    }
+    return undefined
+  }),
+  subscribeAntigravityChatSignIn: vi.fn(
+    async (owner: RuntimeClientTarget, handlers: { onEvent: (status: unknown) => void }) => {
+      const host = fake.hostOf(owner)
+      host.streams.add(handlers.onEvent)
+      handlers.onEvent(fake.status(host))
+      return { unsubscribe: () => host.streams.delete(handlers.onEvent) }
+    }
+  )
+}))
+afterEach(() => cleanup())
+
+async function showRow(owner: RuntimeClientTarget) {
+  const view = render(
+    <TooltipProvider>
+      <AntigravityChatSignInRow
+        owner={owner}
+        label="this computer"
+        description=""
+        disabled={false}
+      />
+    </TooltipProvider>
+  )
+  // Sign in stays disabled until the host's snapshot lands.
+  await act(async () => undefined)
+  return view
+}
+
+it('opens the link once across status answers and shows signed in', async () => {
+  const openUrl = vi.fn(async () => undefined)
+  Object.assign(window, { api: { shell: { openUrl } } })
+  const owner = { kind: 'local' } as const
+  publish(owner, null, 'signedOut')
+  const view = await showRow(owner)
+  await screen.findByText('Not signed in on this computer.')
+  await userEvent.click(screen.getByRole('button', { name: 'Sign in' }))
+  await act(async () => publish(owner, { flowId: 'f', phase: 'waiting', url }))
+  await screen.findByText('Finish signing in in your browser.')
+  await act(async () => publish(owner, { flowId: 'f', phase: 'waiting', url }))
+  // The browser's sign-in is checked with a session before it counts.
+  await act(async () => publish(owner, { flowId: 'f', phase: 'verifying' }))
+  await screen.findByText('Finishing sign-in…')
+  await act(async () => publish(owner, { flowId: 'f', phase: 'signedIn' }, 'signedIn'))
+  await screen.findByText('Signed in on this computer.')
+  expect(screen.getByRole('button', { name: 'Change account' })).toBeTruthy()
+  expect(openUrl).toHaveBeenCalledExactlyOnceWith(url)
+  view.unmount()
+})
+
+it('opens nothing for a Start the host answers after the row unmounts', async () => {
+  const start = Promise.withResolvers<{ flowId: string }>()
+  fake.start = start.promise
+  const openUrl = vi.fn(async () => undefined)
+  Object.assign(window, { api: { shell: { openUrl } } })
+  const owner = { kind: 'environment', environmentId: 'unmounted' } as const
+  const view = await showRow(owner)
+  await userEvent.click(view.getByRole('button', { name: 'Sign in' }))
+  view.unmount()
+  await act(async () => {
+    start.resolve({ flowId: 'late' })
+    publish(owner, { flowId: 'late', phase: 'waiting', url })
+  })
+  expect(openUrl).not.toHaveBeenCalled()
+  fake.start = null
+})
+
+it("shows another client's sign-in without letting this one act on it", async () => {
+  const owner = { kind: 'environment', environmentId: 'idle' } as const
+  publish(owner, { flowId: 'done', phase: 'cancelled' })
+  await showRow(owner)
+  await screen.findByText('Sign-in cancelled.')
+  // Once the host answers, its sign-in replaces the settled flow's outcome.
+  await act(async () => publish(owner, { flowId: 'done', phase: 'cancelled' }, 'signedOut'))
+  await screen.findByText('Not signed in on this computer.')
+  await act(async () => publish(owner, { flowId: null, phase: 'waiting' }))
+  await screen.findByText('Sign-in is in progress in another client.')
+  expect(screen.getByRole('button', { name: 'Sign in' }).hasAttribute('disabled')).toBe(true)
+  expect(screen.queryByRole('button', { name: 'Cancel' })).toBeNull()
+  expect(screen.queryByRole('textbox')).toBeNull()
+})
+
+it('sends the address pasted from a browser on another computer to the host', async () => {
+  const owner = { kind: 'environment', environmentId: 'paste' } as const
+  await showRow(owner)
+  await act(async () => publish(owner, { flowId: 'remote', phase: 'waiting', url }))
+  const continueButton = await screen.findByRole('button', { name: 'Continue' })
+  const pasted = 'http://127.0.0.1:51234/?state=s&code=c'
+  await userEvent.type(screen.getByRole('textbox'), pasted)
+  await userEvent.click(continueButton)
+  expect(callAntigravityChatSignIn).toHaveBeenCalledWith(owner, 'Complete', {
+    flowId: 'remote',
+    callbackUrl: pasted
+  })
+})
diff --git a/src/renderer/src/components/settings/AntigravityChatSignInRow.tsx b/src/renderer/src/components/settings/AntigravityChatSignInRow.tsx
new file mode 100644
index 00000000000..bbfda57cfbc
--- /dev/null
+++ b/src/renderer/src/components/settings/AntigravityChatSignInRow.tsx
@@ -0,0 +1,336 @@
+import { useEffect, useId, useState, useSyncExternalStore } from 'react'
+import { Check, Copy } from 'lucide-react'
+import { translate } from '@/i18n/i18n'
+import { useClipboardTextCopyFeedback } from '@/hooks/use-clipboard-text-copy-feedback'
+import {
+  antigravityChatSignInRunning as running,
+  cancelAntigravityChatSignIn,
+  completeAntigravityChatSignIn,
+  observeAntigravityChatSignIn,
+  readAntigravityChatSignIn,
+  startAntigravityChatSignIn,
+  subscribeAntigravityChatSignIns,
+  type AntigravityChatSignInView
+} from '@/runtime/antigravity-chat-sign-in-status'
+import type { RuntimeClientTarget } from '../../../../shared/runtime-client-target'
+import type {
+  AntigravityChatAuth,
+  AntigravityChatSignInState
+} from '../../../../shared/antigravity-account-types'
+import type { ManagedRuntimeInstallObservation } from '@/runtime/use-managed-runtime-install'
+import { Button } from '../ui/button'
+import { Input } from '../ui/input'
+import { Tooltip, TooltipContent, TooltipTrigger } from '../ui/tooltip'
+
+type Flow = AntigravityChatSignInState
+
+/** A running flow another client started: the host tells only its starter the id. */
+const otherClients = (flow: Flow | null): boolean => running(flow) && flow.flowId === null
+
+function authLine(auth: AntigravityChatAuth, host: string, signedOut: string): string | null {
+  if (auth === 'signedIn') {
+    return translate('accounts.antigravity.chatSignedInOn', 'Signed in on {{host}}.', { host })
+  }
+  return auth === 'signedOut' ? signedOut : null
+}
+
+function chatSignInLine(
+  flow: Flow | null,
+  auth: AntigravityChatAuth,
+  openFailed: boolean,
+  host: string,
+  signedOut: string
+): string | null {
+  if (otherClients(flow)) {
+    return translate(
+      'accounts.antigravity.chatOtherClient',
+      'Sign-in is in progress in another client.'
+    )
+  }
+  switch (flow?.phase) {
+    case 'starting':
+      return translate('accounts.antigravity.chatStarting', 'Starting sign-in…')
+    case 'waiting':
+      return openFailed
+        ? translate(
+            'accounts.antigravity.chatOpenFailed',
+            'Copy the link and open it in your browser.'
+          )
+        : translate('accounts.antigravity.chatWaiting', 'Finish signing in in your browser.')
+    case 'verifying':
+      return translate('accounts.antigravity.chatVerifying', 'Finishing sign-in…')
+    // A settled flow only stands in until the host answers whether it is signed in.
+    case 'cancelled':
+      return (
+        authLine(auth, host, signedOut) ??
+        translate('accounts.antigravity.chatCancelled', 'Sign-in cancelled.')
+      )
+    case 'expired':
+      return (
+        authLine(auth, host, signedOut) ??
+        translate('accounts.antigravity.chatExpired', 'Sign-in timed out. Try again.')
+      )
+    case 'failed':
+    case 'signedIn':
+    case undefined:
+      return authLine(auth, host, signedOut)
+  }
+}
+
+type SignInAction = 'retry' | 'changeAccount' | 'signIn'
+
+function signInAction(
+  flow: Flow | null,
+  auth: AntigravityChatAuth,
+  error: string | null
+): SignInAction {
+  if (
+    error ||
+    flow?.phase === 'failed' ||
+    flow?.phase === 'cancelled' ||
+    flow?.phase === 'expired'
+  ) {
+    return 'retry'
+  }
+  return auth === 'signedIn' ? 'changeAccount' : 'signIn'
+}
+
+const SIGN_IN_ACTION_LABELS: Record<SignInAction, () => string> = {
+  retry: () => translate('accounts.antigravity.chatRetry', 'Retry sign-in'),
+  changeAccount: () => translate('accounts.antigravity.chatChangeAccount', 'Change account'),
+  signIn: () => translate('accounts.antigravity.chatSignIn', 'Sign in')
+}
+
+const SETTLED_OPERATION_PHASES = new Set(['succeeded', 'failed', 'cancelled'])
+
+/** Sign-in runs the installed server, so it waits while the host reports nothing to run or a
+ *  Remove still runs; an Update keeps the old copy running until it lands. The install row beside
+ *  it says why. A status the host could not report leaves it to the host. */
+export function antigravityChatSignInBlocked(
+  install: Extract<ManagedRuntimeInstallObservation, { kind: 'active' }>
+): boolean {
+  const { snapshot } = install
+  if (snapshot.kind !== 'known') {
+    return snapshot.kind === 'unknown'
+  }
+  const { source, operation } = snapshot.state
+  return !source || (operation?.kind === 'remove' && !SETTLED_OPERATION_PHASES.has(operation.phase))
+}
+
+const NOT_FOLLOWED: AntigravityChatSignInView = {
+  status: 'unknown',
+  flow: null,
+  auth: 'unknown',
+  error: null,
+  openFailed: false
+}
+
+/** The host's chat sign-in, followed while `owner` is set; the install row beside it reads it too. */
+export function useAntigravityChatSignIn(
+  owner: RuntimeClientTarget | null
+): AntigravityChatSignInView {
+  const shown = owner !== null
+  const environmentId = owner?.kind === 'environment' ? owner.environmentId : null
+  useEffect(
+    () =>
+      shown
+        ? observeAntigravityChatSignIn(
+            environmentId === null ? { kind: 'local' } : { kind: 'environment', environmentId }
+          )
+        : undefined,
+    [shown, environmentId]
+  )
+  const read = (): AntigravityChatSignInView =>
+    owner ? readAntigravityChatSignIn(owner) : NOT_FOLLOWED
+  return useSyncExternalStore(subscribeAntigravityChatSignIns, read, read)
+}
+
+/** Google's last page points at the host, which a browser on another computer can't reach, so its
+ *  address is pasted here and the host passes it on. */
+export function PastedAddressForm(props: {
+  pending: boolean
+  send: (callbackUrl: string, refused: (message: string) => void) => void
+}): React.JSX.Element {
+  const [pasted, setPasted] = useState('')
+  // The host's refusal of this address; the form leaves once the host takes one.
+  const [refusal, setRefusal] = useState<string | null>(null)
+  const helpId = useId()
+  const callbackUrl = pasted.trim()
+  // noValidate: the browser's URL check would pre-empt the host's refusal, which says what's wrong.
+  return (
+    <form
+      noValidate
+      className="space-y-1"
+      onSubmit={(event) => {
+        event.preventDefault()
+        if (callbackUrl) {
+          props.send(callbackUrl, setRefusal)
+        }
+      }}
+    >
+      <p id={helpId} className="text-xs text-muted-foreground">
+        {translate(
+          'accounts.antigravity.chatPasteHelp',
+          "If the last page after signing in doesn't load, copy its full address from your browser and paste it here."
+        )}
+      </p>
+      <div className="flex items-center gap-2">
+        <Input
+          type="url"
+          autoComplete="off"
+          spellCheck={false}
+          maxLength={16_384}
+          aria-labelledby={helpId}
+          aria-invalid={refusal !== null}
+          value={pasted}
+          disabled={props.pending}
+          onChange={(event) => {
+            setPasted(event.target.value)
+            setRefusal(null)
+          }}
+        />
+        <Button type="submit" size="sm" variant="outline" disabled={props.pending || !callbackUrl}>
+          {translate('accounts.antigravity.chatContinue', 'Continue')}
+        </Button>
+      </div>
+      {refusal !== null && (
+        <p role="alert" className="text-xs text-destructive">
+          {refusal}
+        </p>
+      )}
+    </form>
+  )
+}
+
+/** One host's chat sign-in as both Settings layouts show it. `signedOut` is the line for a host
+ *  that answered it is not signed in. */
+export function useAntigravityChatSignInControls(props: {
+  owner: RuntimeClientTarget
+  label: string
+  signedOut: string
+  disabled: boolean
+}) {
+  const { owner, label } = props
+  const { status, flow, auth, openFailed, ...view } = useAntigravityChatSignIn(owner)
+  // One start, cancel or paste at a time, so a double click asks the host once.
+  const [pending, setPending] = useState(false)
+  const act = (request: () => Promise<void>): void => {
+    setPending(true)
+    void request().finally(() => setPending(false))
+  }
+  const copy = useClipboardTextCopyFeedback(flow?.url ?? '')
+  const failed = translate('accounts.antigravity.chatFailed', 'Sign-in failed. Try again.')
+  const error = view.error === null ? null : view.error || failed
+  const copyFailed = translate('accounts.antigravity.chatCopyFailed', 'Could not copy the link.')
+  const readFailed = translate(
+    'accounts.antigravity.chatReadFailed',
+    'Could not check the sign-in on {{host}}.',
+    { host: label }
+  )
+  const ownFlow = running(flow) && flow.flowId !== null
+  const action = signInAction(flow, auth, error)
+  return {
+    flow,
+    ownFlow,
+    /** The browser's link, while this client's sign-in waits on it. */
+    url: ownFlow && flow?.phase === 'waiting' ? (flow.url ?? null) : null,
+    line:
+      status === 'known' ? chatSignInLine(flow, auth, openFailed, label, props.signedOut) : null,
+    alert:
+      error ??
+      (status === 'readFailed' ? readFailed : null) ??
+      (flow?.phase === 'failed' ? (flow.error ?? failed) : null) ??
+      (copy.status === 'failed' ? copyFailed : null),
+    action,
+    actionLabel: SIGN_IN_ACTION_LABELS[action](),
+    pending,
+    copy,
+    copyLabel: translate('accounts.antigravity.chatCopyLink', 'Copy sign-in link'),
+    signInDisabled: props.disabled || pending || status !== 'known' || otherClients(flow),
+    start: () => act(() => startAntigravityChatSignIn(owner)),
+    cancel: () => act(() => cancelAntigravityChatSignIn(owner)),
+    send: (callbackUrl: string, refused: (message: string) => void) =>
+      act(async () => {
+        const refusal = await completeAntigravityChatSignIn(owner, callbackUrl)
+        if (refusal !== null) {
+          refused(refusal || failed)
+        }
+      })
+  }
+}
+
+/** This execution host's sign-in for Antigravity chats, run by the host's own server. Every row
+ *  for a host shows the same sign-in, a running one included. */
+export function AntigravityChatSignInRow(props: {
+  owner: RuntimeClientTarget
+  label: string
+  description: string
+  disabled: boolean
+}): React.JSX.Element {
+  const signIn = useAntigravityChatSignInControls({
+    owner: props.owner,
+    label: props.label,
+    signedOut: translate('accounts.antigravity.chatNotSignedIn', 'Not signed in on {{host}}.', {
+      host: props.label
+    }),
+    disabled: props.disabled
+  })
+  const { line, alert, copy, copyLabel, url } = signIn
+  return (
+    <div className="space-y-2">
+      <div className="flex items-center justify-between gap-3">
+        <div className="min-w-0 flex-1">
+          <p className="text-sm font-medium leading-none">
+            {translate('accounts.antigravity.chatTitle', 'Antigravity chats')}
+          </p>
+          {props.description ? (
+            <p className="mt-1 text-xs text-muted-foreground">{props.description}</p>
+          ) : null}
+          {/* The line keeps its height until the host answers, so nothing shifts when it does. */}
+          <p role="status" className="mt-1 min-h-4 break-words text-xs text-muted-foreground">
+            {line}
+            {line && alert ? ' ' : null}
+            {alert && (
+              <span role="alert" className="text-destructive">
+                {alert}
+              </span>
+            )}
+          </p>
+        </div>
+        {signIn.ownFlow ? (
+          <div className="flex shrink-0 items-center gap-2">
+            {url && (
+              <Tooltip>
+                <TooltipTrigger asChild>
+                  <Button
+                    size="icon-xs"
+                    variant="ghost"
+                    aria-label={copyLabel}
+                    onClick={() => void copy.copyText()}
+                  >
+                    {copy.status === 'copied' ? <Check /> : <Copy />}
+                  </Button>
+                </TooltipTrigger>
+                <TooltipContent>{copyLabel}</TooltipContent>
+              </Tooltip>
+            )}
+            <Button size="xs" variant="ghost" disabled={signIn.pending} onClick={signIn.cancel}>
+              {translate('accounts.antigravity.chatCancel', 'Cancel')}
+            </Button>
+          </div>
+        ) : (
+          <Button
+            size="xs"
+            // Signed in, the button only switches account, so it steps back from the primary.
+            variant={signIn.action === 'changeAccount' ? 'outline' : 'default'}
+            disabled={signIn.signInDisabled}
+            onClick={signIn.start}
+          >
+            {signIn.actionLabel}
+          </Button>
+        )}
+      </div>
+      {url && <PastedAddressForm pending={signIn.pending} send={signIn.send} />}
+    </div>
+  )
+}
diff --git a/src/renderer/src/components/settings/AntigravityProviderSignInArea.tsx b/src/renderer/src/components/settings/AntigravityProviderSignInArea.tsx
new file mode 100644
index 00000000000..468589cd82d
--- /dev/null
+++ b/src/renderer/src/components/settings/AntigravityProviderSignInArea.tsx
@@ -0,0 +1,93 @@
+import { Check, Copy } from 'lucide-react'
+import { translate } from '@/i18n/i18n'
+import type { ManagedRuntimeInstallObservation } from '@/runtime/use-managed-runtime-install'
+import type { RuntimeClientTarget } from '../../../../shared/runtime-client-target'
+import { LoadingSpinner } from '../LoadingSpinner'
+import { Button } from '../ui/button'
+import {
+  PastedAddressForm,
+  antigravityChatSignInBlocked,
+  useAntigravityChatSignInControls
+} from './AntigravityChatSignInRow'
+
+type ActiveInstall = Extract<ManagedRuntimeInstallObservation, { kind: 'active' }>
+
+const CHANGING_PHASES = new Set(['downloading', 'extracting', 'verifying', 'removing'])
+
+/** Sign-in needs a copy to run, so it stays away while there is none or one is being installed or
+ *  removed; the install line says which. Until the host answers, it holds its place. */
+export function antigravityProviderSignInShown(install: ActiveInstall): boolean {
+  const { snapshot } = install
+  if (snapshot.kind !== 'known') {
+    return true
+  }
+  const { source, operation } = snapshot.state
+  return source !== null && !(operation && CHANGING_PHASES.has(operation.phase))
+}
+
+/** Settings › Chat › Providers' sign-in for Antigravity chats, under its row. */
+export function AntigravityProviderSignInArea(props: {
+  owner: RuntimeClientTarget
+  label: string
+  install: ActiveInstall
+}): React.JSX.Element {
+  const signIn = useAntigravityChatSignInControls({
+    owner: props.owner,
+    label: props.label,
+    signedOut: translate(
+      'settings.chat.providers.antigravityNotSignedIn',
+      'Not signed in. Chats need an Antigravity sign-in, separate from your agy terminal account.'
+    ),
+    disabled: antigravityChatSignInBlocked(props.install)
+  })
+  const { alert, copy, copyLabel, ownFlow, url } = signIn
+  // A settled failure says only why; a running sign-in keeps its step beside a copy failure.
+  const line = alert && !ownFlow ? null : signIn.line
+  return (
+    // Indented to the provider's name, past its icon.
+    <div className="ml-10 space-y-2 rounded-md bg-muted/40 px-3 py-2.5">
+      {/* The line keeps its height until the host answers, so nothing shifts when it does. */}
+      <div className="flex min-h-6 items-center gap-2">
+        <div
+          role="status"
+          className="flex min-w-0 flex-1 items-center gap-1.5 text-xs text-muted-foreground"
+        >
+          {ownFlow ? <LoadingSpinner className="size-3 shrink-0" /> : null}
+          <span className="min-w-0 break-words">
+            {line}
+            {line && alert ? ' ' : null}
+            {alert && (
+              <span role="alert" className="text-destructive">
+                {alert}
+              </span>
+            )}
+          </span>
+        </div>
+        {ownFlow ? (
+          <>
+            {url && (
+              <Button size="xs" variant="ghost" onClick={() => void copy.copyText()}>
+                {copy.status === 'copied' ? <Check /> : <Copy />}
+                {copyLabel}
+              </Button>
+            )}
+            <Button size="xs" variant="ghost" disabled={signIn.pending} onClick={signIn.cancel}>
+              {translate('accounts.antigravity.chatCancel', 'Cancel')}
+            </Button>
+          </>
+        ) : (
+          <Button
+            size="xs"
+            // Signed in, the button only switches account, so it steps back from the primary.
+            variant={signIn.action === 'changeAccount' ? 'ghost' : 'default'}
+            disabled={signIn.signInDisabled}
+            onClick={signIn.start}
+          >
+            {signIn.actionLabel}
+          </Button>
+        )}
+      </div>
+      {url && <PastedAddressForm pending={signIn.pending} send={signIn.send} />}
+    </div>
+  )
+}
diff --git a/src/renderer/src/components/settings/NativeChatProvidersSetting.tsx b/src/renderer/src/components/settings/NativeChatProvidersSetting.tsx
index 8ec00a7e187..5cae155414f 100644
--- a/src/renderer/src/components/settings/NativeChatProvidersSetting.tsx
+++ b/src/renderer/src/components/settings/NativeChatProvidersSetting.tsx
@@ -25,6 +25,13 @@ import { ManagedRuntimeInstallRow } from '../managed-runtime/ManagedRuntimeInsta
 import { SearchableSetting } from './SearchableSetting'
 import { SettingsSubsectionHeader, SettingsSwitch } from './SettingsFormControls'
 import { getChatProvidersSearchEntry } from './chat-providers-search'
+import { antigravityChatSignInRunning } from '@/runtime/antigravity-chat-sign-in-status'
+import { useAntigravityChatSignIn } from './AntigravityChatSignInRow'
+import {
+  AntigravityProviderSignInArea,
+  antigravityProviderSignInShown
+} from './AntigravityProviderSignInArea'
+import { getHostRuntimeLabel, getRuntimeSentenceLabel } from './accounts-pane-runtime'
 
 const enqueueProviderUpdate = createAgentSettingsUpdateQueue()
 
@@ -98,6 +105,12 @@ function ProviderDetail(props: {
   enabledInAgents: boolean
 }): React.JSX.Element {
   const runtime = useManagedRuntimeInstall(CHAT_HOST, props.agent, props.enabledInAgents)
+  // Install and Remove wait for a running sign-in, which runs the installed server.
+  const signIn = useAntigravityChatSignIn(
+    props.agent === 'antigravity' && props.enabledInAgents && runtime.kind === 'active'
+      ? CHAT_HOST
+      : null
+  )
   const summary = (line: React.ReactNode): React.JSX.Element => (
     <div className="min-w-0 flex-1">
       <div className="text-sm font-medium leading-none">{props.label}</div>
@@ -114,17 +127,36 @@ function ProviderDetail(props: {
     )
   }
   return (
-    <ManagedRuntimeInstallRow observation={runtime} agentLabel={props.label}>
-      {(line, button) => (
+    <ManagedRuntimeInstallRow
+      observation={runtime}
+      agentLabel={props.label}
+      signInRunning={antigravityChatSignInRunning(signIn.flow)}
+    >
+      {(line, actions) => (
         <>
           {summary(line)}
-          {button}
+          {actions}
         </>
       )}
     </ManagedRuntimeInstallRow>
   )
 }
 
+/** Antigravity chats sign in on this computer, directly below the program they run. */
+function AntigravityChatProviderSignIn(): React.JSX.Element | null {
+  const runtime = useManagedRuntimeInstall(CHAT_HOST, 'antigravity', true)
+  if (runtime.kind !== 'active' || !antigravityProviderSignInShown(runtime)) {
+    return null
+  }
+  return (
+    <AntigravityProviderSignInArea
+      owner={CHAT_HOST}
+      label={getRuntimeSentenceLabel({ runtime: 'host', label: getHostRuntimeLabel() })}
+      install={runtime}
+    />
+  )
+}
+
 export function NativeChatProvidersSetting({
   settings,
   updateSettings,
@@ -159,34 +191,41 @@ export function NativeChatProvidersSetting({
               const enabledInAgents = isTuiAgentEnabled(agent, settings.disabledTuiAgents)
               const on = isNativeChatProviderDisplayedOn(settings, agent, detectedIds)
               return (
-                <div key={agent} className="flex items-center gap-3 py-3">
-                  <div className="flex size-7 shrink-0 items-center justify-center rounded-md border border-border/50 bg-background/50">
-                    <AgentIcon agent={agent} size={16} />
+                <div key={agent} className="space-y-3 py-3">
+                  <div className="flex items-center gap-3">
+                    <div className="flex size-7 shrink-0 items-center justify-center rounded-md border border-border/50 bg-background/50">
+                      <AgentIcon agent={agent} size={16} />
+                    </div>
+                    <ProviderDetail
+                      agent={agent}
+                      label={label}
+                      installed={detectedIds}
+                      enabledInAgents={enabledInAgents}
+                    />
+                    <SettingsSwitch
+                      checked={on}
+                      disabled={!enabledInAgents}
+                      ariaLabel={translate(
+                        'settings.chat.providers.toggleLabel',
+                        'Open {{value0}} as a chat',
+                        { value0: label }
+                      )}
+                      onChange={() => {
+                        const next = !on
+                        return enqueueProviderUpdate({
+                          getSettings: () => useAppStore.getState().settings,
+                          fallbackSettings: settings,
+                          updateSettings,
+                          buildUpdate: (latest) =>
+                            buildNativeChatProviderUpdate(latest, agent, next)
+                        })
+                      }}
+                    />
                   </div>
-                  <ProviderDetail
-                    agent={agent}
-                    label={label}
-                    installed={detectedIds}
-                    enabledInAgents={enabledInAgents}
-                  />
-                  <SettingsSwitch
-                    checked={on}
-                    disabled={!enabledInAgents}
-                    ariaLabel={translate(
-                      'settings.chat.providers.toggleLabel',
-                      'Open {{value0}} as a chat',
-                      { value0: label }
-                    )}
-                    onChange={() => {
-                      const next = !on
-                      return enqueueProviderUpdate({
-                        getSettings: () => useAppStore.getState().settings,
-                        fallbackSettings: settings,
-                        updateSettings,
-                        buildUpdate: (latest) => buildNativeChatProviderUpdate(latest, agent, next)
-                      })
-                    }}
-                  />
+                  {/* Chats sign in on the host they run on, under the program that serves them. */}
+                  {agent === 'antigravity' && enabledInAgents ? (
+                    <AntigravityChatProviderSignIn />
+                  ) : null}
                 </div>
               )
             })}
diff --git a/src/renderer/src/i18n/en-runtime-required.json b/src/renderer/src/i18n/en-runtime-required.json
index 909bb04264e..a9739ece499 100644
--- a/src/renderer/src/i18n/en-runtime-required.json
+++ b/src/renderer/src/i18n/en-runtime-required.json
@@ -2902,6 +2902,7 @@
         "agentCommandNotSignedIn": "Sign in to {{agent}} with `{{loginCommand}}` on the computer running this chat.",
         "agentNotSignedIn": "Sign in to {{agent}}.",
         "answerUnconfirmed": "Your answer was recorded but the agent did not confirm it.",
+        "antigravityNotSignedIn": "Antigravity isn't signed in. Sign in under Settings → Accounts → Antigravity.",
         "argumentsMissingValue": "Saved Arguments need a value for {{option}}.",
         "argumentsMultipleValues": "Saved Arguments give {{option}} more than one value.",
         "argumentsPositionalPrompt": "Saved Arguments include a prompt.",
diff --git a/src/renderer/src/i18n/locales/en.json b/src/renderer/src/i18n/locales/en.json
index 91bdd78b50c..bb460b5ba0d 100644
--- a/src/renderer/src/i18n/locales/en.json
+++ b/src/renderer/src/i18n/locales/en.json
@@ -216,7 +216,8 @@
         "notInstalled": "Not installed",
         "install": "Install",
         "toggleLabel": "Open {{value0}} as a chat",
-        "antigravityDescription": "Antigravity chats run a server Orca downloads to this host, separate from the agy CLI."
+        "antigravityDescription": "Antigravity chats run a server Orca downloads to this host, separate from the agy CLI.",
+        "antigravityNotSignedIn": "Not signed in. Chats need an Antigravity sign-in, separate from your agy terminal account."
       }
     },
     "terminal": {
@@ -18320,6 +18321,7 @@
         "claudeManagedNotSignedIn": "This Claude account isn't signed in. Sign in again in Claude Accounts settings.",
         "codexSystemNotSignedIn": "Codex isn't signed in. Run `{{loginCommand}}`.",
         "codexManagedNotSignedIn": "This Codex account isn't signed in. Sign in again in Codex Accounts settings.",
+        "antigravityNotSignedIn": "Antigravity isn't signed in. Sign in under Settings → Accounts → Antigravity.",
         "cliMissing": "{{agent}} wasn't found on the computer running this chat. Install it, or check its Command in Settings → Agents.",
         "signInFirst": "Sign in first.",
         "signInThenRunCommand": "Sign in, then run /{{command}} again.",
@@ -19467,12 +19469,14 @@
       "cancelFailed": "Couldn't cancel the installation. Try again.",
       "install": "Install {{agent}}",
       "installManaged": "Install Orca's copy",
-      "installed": "Installed.",
+      "installed": "Installed",
       "notInstalled": "Not installed.",
       "progress": "{{agent}} download",
       "readFailed": "Could not check {{agent}} on this host. Retrying.",
-      "reinstall": "Reinstall",
+      "reinstall": "Reinstall {{agent}}",
+      "reinstallShort": "Reinstall",
       "remove": "Remove downloaded runtime",
+      "moreActions": "More actions for {{agent}}",
       "removeConfirm": "Remove",
       "removeDescription": "{{agent}} chats that are running stop. Their history is kept.",
       "removeKeep": "Cancel",
@@ -20010,6 +20014,27 @@
       "description": "Agents there use the distro's default Claude and Codex accounts until Orca in WSL is updated."
     },
     "antigravity": {
+      "chatTitle": "Antigravity chats",
+      "chatDescription": "Chats use their own Antigravity sign-in, separate from your agy account above. Sign in once on this device.",
+      "chatSignIn": "Sign in",
+      "chatChangeAccount": "Change account",
+      "chatRetry": "Retry sign-in",
+      "chatCancel": "Cancel",
+      "chatCopyLink": "Copy sign-in link",
+      "chatCopyFailed": "Could not copy the link.",
+      "chatStarting": "Starting sign-in…",
+      "chatWaiting": "Finish signing in in your browser.",
+      "chatOpenFailed": "Copy the link and open it in your browser.",
+      "chatVerifying": "Finishing sign-in…",
+      "chatPasteHelp": "If the last page after signing in doesn't load, copy its full address from your browser and paste it here.",
+      "chatContinue": "Continue",
+      "chatSignedInOn": "Signed in on {{host}}.",
+      "chatCancelled": "Sign-in cancelled.",
+      "chatExpired": "Sign-in timed out. Try again.",
+      "chatFailed": "Sign-in failed. Try again.",
+      "chatNotSignedIn": "Not signed in on {{host}}.",
+      "chatOtherClient": "Sign-in is in progress in another client.",
+      "chatReadFailed": "Could not check the sign-in on {{host}}.",
       "scope": "Manage the native agy account on {{host}}.",
       "signIn": "Start agy on this host and complete its browser sign-in, then save the current account. To add a different account, use /logout in agy and sign in again.",
       "docs": "Sign-in instructions",
diff --git a/src/renderer/src/i18n/locales/es.json b/src/renderer/src/i18n/locales/es.json
index 30127b10cfd..089da9f8916 100644
--- a/src/renderer/src/i18n/locales/es.json
+++ b/src/renderer/src/i18n/locales/es.json
@@ -39,7 +39,8 @@
       },
       "providers": {
         "title": "Proveedores",
-        "antigravityDescription": "Los chats de Antigravity usan un servidor que Orca descarga en este host, independiente de la CLI de agy."
+        "antigravityDescription": "Los chats de Antigravity usan un servidor que Orca descarga en este host, independiente de la CLI de agy.",
+        "antigravityNotSignedIn": "No has iniciado sesión. Los chats necesitan un inicio de sesión de Antigravity, independiente de tu cuenta de agy en la terminal."
       }
     },
     "terminal": {
@@ -18060,6 +18061,7 @@
         "claudeManagedNotSignedIn": "Esta cuenta de Claude no ha iniciado sesión. Vuelve a iniciar sesión en la configuración de Cuentas de Claude.",
         "codexSystemNotSignedIn": "Codex no ha iniciado sesión. Ejecuta `{{loginCommand}}`.",
         "codexManagedNotSignedIn": "Esta cuenta de Codex no ha iniciado sesión. Vuelve a iniciar sesión en la configuración de Cuentas de Codex.",
+        "antigravityNotSignedIn": "Antigravity no ha iniciado sesión. Inicia sesión en Ajustes → Cuentas → Antigravity.",
         "cliMissing": "No se encontró {{agent}} en el equipo que ejecuta este chat. Instálelo o revise su Comando en Ajustes → Agentes.",
         "signInFirst": "Inicie sesión primero.",
         "signInThenRunCommand": "Inicie sesión y vuelva a ejecutar /{{command}}.",
@@ -19232,12 +19234,14 @@
       "cancelFailed": "No se pudo cancelar la instalación. Inténtalo de nuevo.",
       "install": "Instalar {{agent}}",
       "installManaged": "Instalar la copia de Orca",
-      "installed": "Instalado.",
+      "installed": "Instalado",
       "notInstalled": "No instalado.",
       "progress": "Descarga de {{agent}}",
       "readFailed": "No se pudo comprobar {{agent}} en este host. Reintentando.",
-      "reinstall": "Reinstalar",
+      "reinstall": "Reinstalar {{agent}}",
+      "reinstallShort": "Reinstalar",
       "remove": "Quitar el runtime descargado",
+      "moreActions": "Más acciones para {{agent}}",
       "removeConfirm": "Quitar",
       "removeDescription": "Los chats de {{agent}} en curso se detienen. Su historial se conserva.",
       "removeKeep": "Cancelar",
@@ -19675,6 +19679,27 @@
       "cancel": "Cancelar"
     },
     "antigravity": {
+      "chatTitle": "Chats de Antigravity",
+      "chatDescription": "Los chats usan su propio inicio de sesión de Antigravity, independiente de tu cuenta de agy de arriba. Inicia sesión una vez en este dispositivo.",
+      "chatSignIn": "Iniciar sesión",
+      "chatChangeAccount": "Cambiar de cuenta",
+      "chatRetry": "Reintentar inicio de sesión",
+      "chatCancel": "Cancelar",
+      "chatCopyLink": "Copiar enlace de inicio de sesión",
+      "chatCopyFailed": "No se pudo copiar el enlace.",
+      "chatStarting": "Iniciando sesión…",
+      "chatWaiting": "Termina de iniciar sesión en tu navegador.",
+      "chatOpenFailed": "Copia el enlace y ábrelo en tu navegador.",
+      "chatVerifying": "Finalizando el inicio de sesión…",
+      "chatPasteHelp": "Si la última página después de iniciar sesión no carga, copia su dirección completa desde el navegador y pégala aquí.",
+      "chatContinue": "Continuar",
+      "chatSignedInOn": "Sesión iniciada en {{host}}.",
+      "chatCancelled": "Inicio de sesión cancelado.",
+      "chatExpired": "El inicio de sesión caducó. Inténtalo de nuevo.",
+      "chatFailed": "No se pudo iniciar sesión. Inténtalo de nuevo.",
+      "chatNotSignedIn": "No has iniciado sesión en {{host}}.",
+      "chatOtherClient": "Hay un inicio de sesión en curso en otro cliente.",
+      "chatReadFailed": "No se pudo comprobar el inicio de sesión en {{host}}.",
       "retry": "Reintentar",
       "remove": "Eliminar",
       "usage": "Actualizar uso",
diff --git a/src/renderer/src/i18n/locales/fr.json b/src/renderer/src/i18n/locales/fr.json
index 727e00d12f5..5e7994b4737 100644
--- a/src/renderer/src/i18n/locales/fr.json
+++ b/src/renderer/src/i18n/locales/fr.json
@@ -143,7 +143,8 @@
       },
       "providers": {
         "title": "Fournisseurs",
-        "antigravityDescription": "Les chats Antigravity utilisent un serveur qu’Orca télécharge sur cet hôte, distinct de la CLI agy."
+        "antigravityDescription": "Les chats Antigravity utilisent un serveur qu’Orca télécharge sur cet hôte, distinct de la CLI agy.",
+        "antigravityNotSignedIn": "Non connecté. Les discussions nécessitent une connexion Antigravity, distincte de votre compte agy du terminal."
       }
     },
     "terminal": {
@@ -18169,6 +18170,7 @@
         "claudeManagedNotSignedIn": "Ce compte Claude n’est pas connecté. Reconnectez-vous dans les paramètres des Comptes Claude.",
         "codexSystemNotSignedIn": "Codex n’est pas connecté. Exécutez `{{loginCommand}}`.",
         "codexManagedNotSignedIn": "Ce compte Codex n’est pas connecté. Reconnectez-vous dans les paramètres des Comptes Codex.",
+        "antigravityNotSignedIn": "Antigravity n’est pas connecté. Connectez-vous dans Paramètres → Comptes → Antigravity.",
         "cliMissing": "{{agent}} est introuvable sur l’ordinateur qui exécute cette conversation. Installez-le ou vérifiez sa Commande dans Paramètres → Agents.",
         "signInFirst": "Connectez-vous d'abord.",
         "signInThenRunCommand": "Connectez-vous, puis relancez /{{command}}.",
@@ -19348,12 +19350,14 @@
       "cancelFailed": "Impossible d'annuler l'installation. Réessayez.",
       "install": "Installer {{agent}}",
       "installManaged": "Installer la copie d'Orca",
-      "installed": "Installé.",
+      "installed": "Installé",
       "notInstalled": "Non installé.",
       "progress": "Téléchargement de {{agent}}",
       "readFailed": "Impossible de vérifier {{agent}} sur cet hôte. Nouvel essai en cours.",
-      "reinstall": "Réinstaller",
+      "reinstall": "Réinstaller {{agent}}",
+      "reinstallShort": "Réinstaller",
       "remove": "Supprimer le runtime téléchargé",
+      "moreActions": "Plus d'actions pour {{agent}}",
       "removeConfirm": "Supprimer",
       "removeDescription": "Les chats {{agent}} en cours s'arrêtent. Leur historique est conservé.",
       "removeKeep": "Annuler",
@@ -19828,6 +19832,27 @@
       "cancel": "Annuler"
     },
     "antigravity": {
+      "chatTitle": "Discussions Antigravity",
+      "chatDescription": "Les discussions utilisent leur propre connexion Antigravity, distincte de votre compte agy ci-dessus. Connectez-vous une seule fois sur cet appareil.",
+      "chatSignIn": "Se connecter",
+      "chatChangeAccount": "Changer de compte",
+      "chatRetry": "Réessayer la connexion",
+      "chatCancel": "Annuler",
+      "chatCopyLink": "Copier le lien de connexion",
+      "chatCopyFailed": "Impossible de copier le lien.",
+      "chatStarting": "Démarrage de la connexion…",
+      "chatWaiting": "Terminez la connexion dans votre navigateur.",
+      "chatOpenFailed": "Copiez le lien et ouvrez-le dans votre navigateur.",
+      "chatVerifying": "Finalisation de la connexion…",
+      "chatPasteHelp": "Si la dernière page après la connexion ne se charge pas, copiez son adresse complète depuis votre navigateur et collez-la ici.",
+      "chatContinue": "Continuer",
+      "chatSignedInOn": "Connecté sur {{host}}.",
+      "chatCancelled": "Connexion annulée.",
+      "chatExpired": "La connexion a expiré. Réessayez.",
+      "chatFailed": "La connexion a échoué. Réessayez.",
+      "chatNotSignedIn": "Non connecté sur {{host}}.",
+      "chatOtherClient": "Une connexion est en cours dans un autre client.",
+      "chatReadFailed": "Impossible de vérifier la connexion sur {{host}}.",
       "scope": "Gérez le compte agy natif sur {{host}}.",
       "signIn": "Démarrez agy sur cet hôte et complétez la connexion au navigateur, puis enregistrez le compte actuel. Pour ajouter un autre compte, utilisez /logout dans agy et reconnectez-vous.",
       "docs": "Instructions de connexion",
diff --git a/src/renderer/src/i18n/locales/ja.json b/src/renderer/src/i18n/locales/ja.json
index 6e241475cf3..3c0675ee201 100644
--- a/src/renderer/src/i18n/locales/ja.json
+++ b/src/renderer/src/i18n/locales/ja.json
@@ -39,7 +39,8 @@
       },
       "providers": {
         "title": "プロバイダー",
-        "antigravityDescription": "Antigravity チャットは、Orca がこのホストにダウンロードするサーバーで動作します。agy CLI とは別です。"
+        "antigravityDescription": "Antigravity チャットは、Orca がこのホストにダウンロードするサーバーで動作します。agy CLI とは別です。",
+        "antigravityNotSignedIn": "サインインしていません。チャットには、ターミナルの agy アカウントとは別の Antigravity サインインが必要です。"
       }
     },
     "terminal": {
@@ -18100,6 +18101,7 @@
         "claudeManagedNotSignedIn": "この Claude アカウントにサインインしていません。設定の Claude アカウントで再度サインインしてください。",
         "codexSystemNotSignedIn": "Codex にサインインしていません。`{{loginCommand}}` を実行してください。",
         "codexManagedNotSignedIn": "この Codex アカウントにサインインしていません。設定の Codex アカウントで再度サインインしてください。",
+        "antigravityNotSignedIn": "Antigravity にサインインしていません。[設定] → [アカウント] → [Antigravity] でサインインしてください。",
         "cliMissing": "このチャットを実行しているコンピューターで {{agent}} が見つかりませんでした。インストールするか、[設定] → [Agent] の [コマンド] を確認してください。",
         "signInFirst": "先にサインインしてください。",
         "signInThenRunCommand": "サインインしてから、/{{command}} をもう一度実行してください。",
@@ -19244,12 +19246,14 @@
       "cancelFailed": "インストールをキャンセルできませんでした。もう一度お試しください。",
       "install": "{{agent}} をインストール",
       "installManaged": "Orca のコピーをインストール",
-      "installed": "インストール済みです。",
+      "installed": "インストール済み",
       "notInstalled": "インストールされていません。",
       "progress": "{{agent}} のダウンロード",
       "readFailed": "このホストの {{agent}} を確認できませんでした。再試行しています。",
-      "reinstall": "再インストール",
+      "reinstall": "{{agent}} を再インストール",
+      "reinstallShort": "再インストール",
       "remove": "ダウンロードしたランタイムを削除",
+      "moreActions": "{{agent}}の追加操作",
       "removeConfirm": "削除",
       "removeDescription": "実行中の {{agent}} チャットは停止します。履歴は保持されます。",
       "removeKeep": "キャンセル",
@@ -19828,6 +19832,27 @@
       "cancel": "キャンセル"
     },
     "antigravity": {
+      "chatTitle": "Antigravity チャット",
+      "chatDescription": "チャットは上の agy アカウントとは別の、独自の Antigravity サインインを使用します。このデバイスで一度サインインしてください。",
+      "chatSignIn": "サインイン",
+      "chatChangeAccount": "アカウントを変更",
+      "chatRetry": "サインインを再試行",
+      "chatCancel": "キャンセル",
+      "chatCopyLink": "サインインリンクをコピー",
+      "chatCopyFailed": "リンクをコピーできませんでした。",
+      "chatStarting": "サインインを開始しています…",
+      "chatWaiting": "ブラウザーでサインインを完了してください。",
+      "chatOpenFailed": "リンクをコピーしてブラウザーで開いてください。",
+      "chatVerifying": "サインインを完了しています…",
+      "chatPasteHelp": "サインイン後の最後のページが読み込まれない場合は、ブラウザーからそのページの完全なアドレスをコピーしてここに貼り付けてください。",
+      "chatContinue": "続行",
+      "chatSignedInOn": "{{host}} でサインイン済みです。",
+      "chatCancelled": "サインインをキャンセルしました。",
+      "chatExpired": "サインインがタイムアウトしました。もう一度お試しください。",
+      "chatFailed": "サインインに失敗しました。もう一度お試しください。",
+      "chatNotSignedIn": "{{host}} でサインインしていません。",
+      "chatOtherClient": "別のクライアントでサインインが進行中です。",
+      "chatReadFailed": "{{host}} のサインインを確認できませんでした。",
       "scope": "{{host}} でネイティブ agy アカウントを管理します。",
       "signIn": "このホストで agy を起動し、ブラウザのサインインを完了して、現在のアカウントを保存します。別のアカウントを追加するには、agy で /logout を使用し、再度サインインします。",
       "docs": "サインイン手順",
diff --git a/src/renderer/src/i18n/locales/ko.json b/src/renderer/src/i18n/locales/ko.json
index 3e3ac2c90ed..a710e5c2751 100644
--- a/src/renderer/src/i18n/locales/ko.json
+++ b/src/renderer/src/i18n/locales/ko.json
@@ -39,7 +39,8 @@
       },
       "providers": {
         "title": "공급자",
-        "antigravityDescription": "Antigravity 채팅은 Orca가 이 호스트에 다운로드하는 서버에서 실행되며, agy CLI와는 별개입니다."
+        "antigravityDescription": "Antigravity 채팅은 Orca가 이 호스트에 다운로드하는 서버에서 실행되며, agy CLI와는 별개입니다.",
+        "antigravityNotSignedIn": "로그인되어 있지 않습니다. 채팅에는 터미널 agy 계정과 별개인 Antigravity 로그인이 필요합니다."
       }
     },
     "terminal": {
@@ -18100,6 +18101,7 @@
         "claudeManagedNotSignedIn": "이 Claude 계정에 로그인하지 않았습니다. Claude 계정 설정에서 다시 로그인하세요.",
         "codexSystemNotSignedIn": "Codex에 로그인하지 않았습니다. `{{loginCommand}}`을 실행하세요.",
         "codexManagedNotSignedIn": "이 Codex 계정에 로그인하지 않았습니다. Codex 계정 설정에서 다시 로그인하세요.",
+        "antigravityNotSignedIn": "Antigravity에 로그인되어 있지 않습니다. 설정 → 계정 → Antigravity에서 로그인하세요.",
         "cliMissing": "이 채팅을 실행하는 컴퓨터에서 {{agent}}를 찾을 수 없습니다. 설치하거나 설정 → 에이전트에서 명령을 확인하세요.",
         "signInFirst": "먼저 로그인하세요.",
         "signInThenRunCommand": "로그인한 다음 /{{command}}을(를) 다시 실행하세요.",
@@ -19244,12 +19246,14 @@
       "cancelFailed": "설치를 취소하지 못했습니다. 다시 시도하세요.",
       "install": "{{agent}} 설치",
       "installManaged": "Orca 사본 설치",
-      "installed": "설치되었습니다.",
+      "installed": "설치됨",
       "notInstalled": "설치되지 않았습니다.",
       "progress": "{{agent}} 다운로드",
       "readFailed": "이 호스트에서 {{agent}}을(를) 확인할 수 없습니다. 다시 시도하는 중입니다.",
-      "reinstall": "재설치",
+      "reinstall": "{{agent}} 재설치",
+      "reinstallShort": "재설치",
       "remove": "다운로드한 런타임 제거",
+      "moreActions": "{{agent}}의 더 많은 작업",
       "removeConfirm": "제거",
       "removeDescription": "실행 중인 {{agent}} 채팅이 중지됩니다. 기록은 유지됩니다.",
       "removeKeep": "취소",
@@ -19828,6 +19832,27 @@
       "cancel": "취소"
     },
     "antigravity": {
+      "chatTitle": "Antigravity 채팅",
+      "chatDescription": "채팅은 위의 agy 계정과 별개인 자체 Antigravity 로그인을 사용합니다. 이 기기에서 한 번 로그인하세요.",
+      "chatSignIn": "로그인",
+      "chatChangeAccount": "계정 변경",
+      "chatRetry": "로그인 다시 시도",
+      "chatCancel": "취소",
+      "chatCopyLink": "로그인 링크 복사",
+      "chatCopyFailed": "링크를 복사할 수 없습니다.",
+      "chatStarting": "로그인을 시작하는 중…",
+      "chatWaiting": "브라우저에서 로그인을 완료하세요.",
+      "chatOpenFailed": "링크를 복사해 브라우저에서 여세요.",
+      "chatVerifying": "로그인을 마무리하는 중…",
+      "chatPasteHelp": "로그인 후 마지막 페이지가 열리지 않으면 브라우저에서 그 페이지의 전체 주소를 복사해 여기에 붙여 넣으세요.",
+      "chatContinue": "계속",
+      "chatSignedInOn": "{{host}}에 로그인되어 있습니다.",
+      "chatCancelled": "로그인이 취소되었습니다.",
+      "chatExpired": "로그인 시간이 초과되었습니다. 다시 시도하세요.",
+      "chatFailed": "로그인하지 못했습니다. 다시 시도하세요.",
+      "chatNotSignedIn": "{{host}}에 로그인되어 있지 않습니다.",
+      "chatOtherClient": "다른 클라이언트에서 로그인이 진행 중입니다.",
+      "chatReadFailed": "{{host}}의 로그인을 확인할 수 없습니다.",
       "scope": "{{host}}의 agy 자체 계정을 관리합니다.",
       "signIn": "이 호스트에서 agy를 실행하고 브라우저 로그인을 완료한 후 현재 계정을 저장하세요. 다른 계정을 추가하려면 agy에서 /logout 명령을 실행하고 다시 로그인하세요.",
       "docs": "로그인 안내",
diff --git a/src/renderer/src/i18n/locales/zh.json b/src/renderer/src/i18n/locales/zh.json
index 64eab50aaee..6f9b51f6e05 100644
--- a/src/renderer/src/i18n/locales/zh.json
+++ b/src/renderer/src/i18n/locales/zh.json
@@ -39,7 +39,8 @@
       },
       "providers": {
         "title": "提供方",
-        "antigravityDescription": "Antigravity 聊天运行在 Orca 下载到此主机的服务器上，与 agy CLI 相互独立。"
+        "antigravityDescription": "Antigravity 聊天运行在 Orca 下载到此主机的服务器上，与 agy CLI 相互独立。",
+        "antigravityNotSignedIn": "未登录。聊天需要单独的 Antigravity 登录，与终端中的 agy 帐户分开。"
       }
     },
     "terminal": {
@@ -18065,6 +18066,7 @@
         "claudeManagedNotSignedIn": "此 Claude 账户尚未登录。请在 Claude 账户设置中重新登录。",
         "codexSystemNotSignedIn": "Codex 尚未登录。请运行 `{{loginCommand}}`。",
         "codexManagedNotSignedIn": "此 Codex 账户尚未登录。请在 Codex 账户设置中重新登录。",
+        "antigravityNotSignedIn": "Antigravity 尚未登录。请在设置 → 账户 → Antigravity 中登录。",
         "cliMissing": "在运行此聊天的计算机上找不到 {{agent}}。请安装它，或检查设置 → 智能体中的命令。",
         "signInFirst": "请先登录。",
         "signInThenRunCommand": "请登录，然后重新运行 /{{command}}。",
@@ -19244,12 +19246,14 @@
       "cancelFailed": "无法取消安装。请重试。",
       "install": "安装 {{agent}}",
       "installManaged": "安装 Orca 的副本",
-      "installed": "已安装。",
+      "installed": "已安装",
       "notInstalled": "未安装。",
       "progress": "{{agent}} 下载",
       "readFailed": "无法检查此主机上的 {{agent}}。正在重试。",
-      "reinstall": "重新安装",
+      "reinstall": "重新安装 {{agent}}",
+      "reinstallShort": "重新安装",
       "remove": "移除已下载的运行时",
+      "moreActions": "{{agent}} 的更多操作",
       "removeConfirm": "移除",
       "removeDescription": "正在运行的 {{agent}} 聊天会停止。其历史记录会保留。",
       "removeKeep": "取消",
@@ -19828,6 +19832,27 @@
       "cancel": "取消"
     },
     "antigravity": {
+      "chatTitle": "Antigravity 聊天",
+      "chatDescription": "聊天使用自己的 Antigravity 登录，与上方的 agy 帐户分开。在此设备上登录一次即可。",
+      "chatSignIn": "登录",
+      "chatChangeAccount": "更换帐户",
+      "chatRetry": "重试登录",
+      "chatCancel": "取消",
+      "chatCopyLink": "复制登录链接",
+      "chatCopyFailed": "无法复制链接。",
+      "chatStarting": "正在开始登录…",
+      "chatWaiting": "请在浏览器中完成登录。",
+      "chatOpenFailed": "复制链接并在浏览器中打开。",
+      "chatVerifying": "正在完成登录…",
+      "chatPasteHelp": "如果登录后的最后一个页面无法加载，请从浏览器复制它的完整地址并粘贴到这里。",
+      "chatContinue": "继续",
+      "chatSignedInOn": "已在 {{host}} 上登录。",
+      "chatCancelled": "已取消登录。",
+      "chatExpired": "登录超时。请重试。",
+      "chatFailed": "登录失败。请重试。",
+      "chatNotSignedIn": "未在 {{host}} 上登录。",
+      "chatOtherClient": "另一个客户端正在登录。",
+      "chatReadFailed": "无法检查 {{host}} 上的登录。",
       "scope": "管理 {{host}} 上的本机 agy 帐户。",
       "signIn": "在此主机上启动 agy 并完成其浏览器登录，然后保存当前帐户。要添加其他帐户，请在 agy 中使用 /logout 并再次登录。",
       "docs": "登录说明",
diff --git a/src/renderer/src/runtime/antigravity-chat-sign-in-status.ts b/src/renderer/src/runtime/antigravity-chat-sign-in-status.ts
new file mode 100644
index 00000000000..8be8b2efe0b
--- /dev/null
+++ b/src/renderer/src/runtime/antigravity-chat-sign-in-status.ts
@@ -0,0 +1,189 @@
+import type {
+  AntigravityChatAuth,
+  AntigravityChatSignInState,
+  AntigravityChatSignInStatus
+} from '../../../shared/antigravity-account-types'
+import type { RuntimeClientTarget } from '../../../shared/runtime-client-target'
+import {
+  createRevisionedHostStateStore,
+  type RevisionedHostSnapshot
+} from './revisioned-host-state-store'
+import {
+  callAntigravityChatSignIn,
+  subscribeAntigravityChatSignIn
+} from './runtime-antigravity-accounts-client'
+
+/**
+ * Each host's Antigravity chat sign-in, followed like an install's status: every Settings row for
+ * a host shows the same flow and the server's last sign-in answer, from another client's flow too.
+ */
+
+export type AntigravityChatSignInView = {
+  /** Whether the host has answered; `readFailed` says nothing about the sign-in. */
+  status: RevisionedHostSnapshot<AntigravityChatSignInStatus>['kind']
+  flow: AntigravityChatSignInState | null
+  auth: AntigravityChatAuth
+  /** Why this client's last request failed; empty when it gave no reason. */
+  error: string | null
+  /** The browser could not open the link this client asked for. */
+  openFailed: boolean
+}
+
+type Notes = Pick<AntigravityChatSignInView, 'error' | 'openFailed'>
+type Local = {
+  owner: RuntimeClientTarget
+  observers: number
+  /** The flow this client started while shown, whose link it opens once. */
+  opens: string | null
+  starts: number
+  notes: Notes
+}
+
+const NO_NOTES: Notes = { error: null, openFailed: false }
+const hostKey = (owner: RuntimeClientTarget): string =>
+  owner.kind === 'local' ? '' : owner.environmentId
+
+const signIns = createRevisionedHostStateStore<RuntimeClientTarget, AntigravityChatSignInStatus>({
+  key: hostKey,
+  hostKey,
+  subscribe: subscribeAntigravityChatSignIn
+})
+const locals = new Map<string, Local>()
+type Shown = {
+  snapshot: RevisionedHostSnapshot<AntigravityChatSignInStatus>
+  notes: Notes
+  view: AntigravityChatSignInView
+}
+const views = new Map<string, Shown>()
+const listeners = new Set<() => void>()
+
+export const antigravityChatSignInRunning = (
+  flow: AntigravityChatSignInState | null
+): flow is AntigravityChatSignInState =>
+  flow?.phase === 'starting' || flow?.phase === 'waiting' || flow?.phase === 'verifying'
+
+const flowOf = (owner: RuntimeClientTarget): AntigravityChatSignInState | null => {
+  const snapshot = signIns.read(owner)
+  return snapshot.kind === 'known' ? snapshot.state.flow : null
+}
+
+function localFor(owner: RuntimeClientTarget): Local {
+  let local = locals.get(hostKey(owner))
+  if (!local) {
+    local = { owner, observers: 0, opens: null, starts: 0, notes: NO_NOTES }
+    locals.set(hostKey(owner), local)
+  }
+  return local
+}
+
+function note(local: Local, patch: Partial<Notes>): void {
+  local.notes = { ...local.notes, ...patch }
+  listeners.forEach((listener) => listener())
+}
+
+const message = (cause: unknown): string => (cause instanceof Error ? cause.message : '')
+
+/** Opens the link of a flow this client started, once, when the host first shows it. */
+function openStartedLinks(): void {
+  for (const local of locals.values()) {
+    const flow = flowOf(local.owner)
+    if (local.opens && flow?.flowId === local.opens && flow.phase === 'waiting' && flow.url) {
+      const { flowId } = flow
+      local.opens = null
+      void window.api.shell.openUrl(flow.url).catch(() => {
+        if (flowOf(local.owner)?.flowId === flowId) {
+          note(local, { openFailed: true })
+        }
+      })
+    }
+  }
+}
+signIns.subscribe(openStartedLinks)
+
+/** Starts a sign-in on the host, or rejoins this client's running one; the host's status shows it. */
+export async function startAntigravityChatSignIn(owner: RuntimeClientTarget): Promise<void> {
+  const local = localFor(owner)
+  const ticket = ++local.starts
+  note(local, NO_NOTES)
+  try {
+    const { flowId } = await callAntigravityChatSignIn<{ flowId: string }>(owner, 'Start')
+    // A row that left before the host answered opens nothing; one shown later shows the flow.
+    if (ticket === local.starts) {
+      local.opens = local.observers > 0 ? flowId : null
+      openStartedLinks()
+    }
+  } catch (cause) {
+    if (ticket === local.starts) {
+      note(local, { error: message(cause) })
+    }
+  }
+}
+
+/** Only the client that started a flow is told its id, so only it can cancel or complete it. */
+const ownFlowId = (owner: RuntimeClientTarget): string | null => flowOf(owner)?.flowId ?? null
+
+export async function cancelAntigravityChatSignIn(owner: RuntimeClientTarget): Promise<void> {
+  const flowId = ownFlowId(owner)
+  if (flowId) {
+    await callAntigravityChatSignIn(owner, 'Cancel', { flowId }).catch(
+      (cause: unknown) => note(localFor(owner), { error: message(cause) })
+    )
+  }
+}
+
+/** Sends the address the browser ended on to the host, for a browser on another computer.
+ *  Resolves to the host's refusal, empty when it gave no reason, or null once it took it. */
+export async function completeAntigravityChatSignIn(
+  owner: RuntimeClientTarget,
+  callbackUrl: string
+): Promise<string | null> {
+  const flowId = ownFlowId(owner)
+  if (!flowId) {
+    return ''
+  }
+  return callAntigravityChatSignIn(owner, 'Complete', { flowId, callbackUrl }).then(
+    () => null,
+    message
+  )
+}
+
+/** Follows the host's sign-in while a row shows it. Returns the release. */
+export function observeAntigravityChatSignIn(owner: RuntimeClientTarget): () => void {
+  const local = localFor(owner)
+  local.observers += 1
+  const release = signIns.observe(owner)
+  return () => {
+    release()
+    local.observers -= 1
+    if (local.observers === 0) {
+      local.opens = null
+    }
+  }
+}
+
+export function readAntigravityChatSignIn(owner: RuntimeClientTarget): AntigravityChatSignInView {
+  const snapshot = signIns.read(owner)
+  const notes = locals.get(hostKey(owner))?.notes ?? NO_NOTES
+  const cached = views.get(hostKey(owner))
+  if (cached?.snapshot === snapshot && cached.notes === notes) {
+    return cached.view
+  }
+  const known = snapshot.kind === 'known' ? snapshot.state : null
+  const view = {
+    status: snapshot.kind,
+    flow: known?.flow ?? null,
+    auth: known?.auth ?? 'unknown',
+    ...notes
+  }
+  views.set(hostKey(owner), { snapshot, notes, view })
+  return view
+}
+
+export function subscribeAntigravityChatSignIns(listener: () => void): () => void {
+  listeners.add(listener)
+  const unsubscribe = signIns.subscribe(listener)
+  return () => {
+    listeners.delete(listener)
+    unsubscribe()
+  }
+}
diff --git a/src/renderer/src/runtime/managed-runtime-install-status.ts b/src/renderer/src/runtime/managed-runtime-install-status.ts
index 2285e4520e5..03b4458526b 100644
--- a/src/renderer/src/runtime/managed-runtime-install-status.ts
+++ b/src/renderer/src/runtime/managed-runtime-install-status.ts
@@ -1,13 +1,15 @@
 import type { ManagedRuntimeInstallState } from '../../../shared/managed-runtime-install'
 import type { RuntimeClientTarget } from '../../../shared/runtime-client-target'
+import {
+  createRevisionedHostStateStore,
+  type RevisionedHostSnapshot
+} from './revisioned-host-state-store'
 import { callRuntimeRpc } from './runtime-rpc-client'
 import { subscribeRuntimeRpc } from './runtime-rpc-subscribe'
 
 /**
  * What each host says about the runtime it installs for an agent, one entry per host runtime
- * instance and agent, so Settings and a chat read the same answer. While any surface observes
- * an entry, one subscription carries the host's pushed state, idle included, so another client's
- * change shows up too; the last surface leaving ends it.
+ * instance and agent, so Settings and a chat read the same answer.
  */
 
 export type ManagedRuntimeInstallSubject = {
@@ -17,163 +19,27 @@ export type ManagedRuntimeInstallSubject = {
   agent: string
 }
 
-export type ManagedRuntimeInstallSnapshot =
-  | { kind: 'unknown' }
-  /** No answer yet and the last read failed: says nothing about whether it is installed. */
-  | { kind: 'readFailed' }
-  | { kind: 'known'; state: ManagedRuntimeInstallState }
-
-type Entry = {
-  subject: ManagedRuntimeInstallSubject
-  snapshot: ManagedRuntimeInstallSnapshot
-  observers: number
-  /** Bumped by every subscribe and every loss; a frame from another generation is stale. */
-  generation: number
-  /** The generation the shown state came from: revisions only order one subscription's frames. */
-  shownGeneration: number
-  stream: { unsubscribe: () => void } | null
-  retry: ReturnType<typeof setTimeout> | null
-  failures: number
-}
-
-const UNKNOWN: ManagedRuntimeInstallSnapshot = { kind: 'unknown' }
-
-const entries = new Map<string, Entry>()
-const listeners = new Set<() => void>()
+export type ManagedRuntimeInstallSnapshot = RevisionedHostSnapshot<ManagedRuntimeInstallState>
 
 const hostAgentKey = ({ target, agent }: ManagedRuntimeInstallSubject): string =>
   `${target.kind === 'local' ? '' : target.environmentId}\u0000${agent}`
-const subjectKey = (subject: ManagedRuntimeInstallSubject): string =>
-  `${hostAgentKey(subject)}\u0000${subject.runtimeId ?? ''}`
 
-function setSnapshot(entry: Entry, snapshot: ManagedRuntimeInstallSnapshot): void {
-  entry.snapshot = snapshot
-  listeners.forEach((listener) => listener())
-}
-
-function entryFor(subject: ManagedRuntimeInstallSubject): Entry {
-  const key = subjectKey(subject)
-  let entry = entries.get(key)
-  if (!entry) {
-    // A restarted host runtime answers under a new key; the old one's answer is stale.
-    for (const [otherKey, other] of entries) {
-      if (other.observers === 0 && hostAgentKey(other.subject) === hostAgentKey(subject)) {
-        entries.delete(otherKey)
-      }
-    }
-    entry = {
-      subject,
-      snapshot: UNKNOWN,
-      observers: 0,
-      generation: 0,
-      shownGeneration: 0,
-      stream: null,
-      retry: null,
-      failures: 0
-    }
-    entries.set(key, entry)
-  }
-  return entry
-}
-
-function accept(entry: Entry, state: ManagedRuntimeInstallState, generation: number): void {
-  // A new subscription may reach a restarted host whose revisions start again at 0.
-  if (
-    entry.snapshot.kind !== 'known' ||
-    generation !== entry.shownGeneration ||
-    entry.snapshot.state.revision < state.revision
-  ) {
-    entry.shownGeneration = generation
-    setSnapshot(entry, { kind: 'known', state })
-  }
-}
-
-const isInstallState = (value: unknown): value is ManagedRuntimeInstallState =>
-  typeof value === 'object' &&
-  value !== null &&
-  'revision' in value &&
-  typeof value.revision === 'number'
-
-function close(entry: Entry): void {
-  entry.generation += 1
-  entry.stream?.unsubscribe()
-  entry.stream = null
-  if (entry.retry) {
-    clearTimeout(entry.retry)
-    entry.retry = null
-  }
-}
-
-function open(entry: Entry): void {
-  close(entry)
-  const { generation, subject } = entry
-  const current = (): boolean => entry.observers > 0 && entry.generation === generation
-  const lost = (): void => {
-    if (!current()) {
-      return
-    }
-    close(entry)
-    // A known answer stays through a blip; only a first read failing changes what is shown.
-    if (entry.snapshot.kind !== 'known') {
-      setSnapshot(entry, { kind: 'readFailed' })
-    }
-    entry.failures += 1
-    const delay = Math.min(30_000, 1000 * 2 ** (entry.failures - 1))
-    entry.retry = setTimeout(() => open(entry), delay)
-  }
-  void subscribeRuntimeRpc(
-    subject.target,
-    'managedRuntime.subscribe',
-    { agent: subject.agent },
-    {
-      onEvent: (result) => {
-        if (current() && isInstallState(result)) {
-          entry.failures = 0
-          accept(entry, result, generation)
-        }
-      },
-      onError: lost,
-      onClose: lost
-    }
-  ).then((opened) => {
-    if (current()) {
-      entry.stream = opened
-    } else {
-      opened.unsubscribe()
-    }
-  }, lost)
-}
-
-export function readManagedRuntimeInstall(
-  subject: ManagedRuntimeInstallSubject
-): ManagedRuntimeInstallSnapshot {
-  return entries.get(subjectKey(subject))?.snapshot ?? UNKNOWN
-}
+const installs = createRevisionedHostStateStore<
+  ManagedRuntimeInstallSubject,
+  ManagedRuntimeInstallState
+>({
+  key: (subject) => `${hostAgentKey(subject)}\u0000${subject.runtimeId ?? ''}`,
+  hostKey: hostAgentKey,
+  subscribe: ({ target, agent }, handlers) =>
+    subscribeRuntimeRpc(target, 'managedRuntime.subscribe', { agent }, handlers)
+})
 
+export const readManagedRuntimeInstall = installs.read
 /** Subscribes while at least one shown surface observes this subject. Returns the release. */
-export function observeManagedRuntimeInstall(subject: ManagedRuntimeInstallSubject): () => void {
-  const entry = entryFor(subject)
-  entry.observers += 1
-  if (entry.observers === 1) {
-    entry.failures = 0
-    open(entry)
-  }
-  return () => {
-    entry.observers -= 1
-    if (entry.observers === 0) {
-      close(entry)
-    }
-  }
-}
-
+export const observeManagedRuntimeInstall = installs.observe
 /** Resubscribes a lost stream at once, e.g. when the host answers again after an outage. */
-export function wakeManagedRuntimeInstall(subject: ManagedRuntimeInstallSubject): void {
-  const entry = entries.get(subjectKey(subject))
-  if (entry?.retry) {
-    entry.failures = 0
-    open(entry)
-  }
-}
+export const wakeManagedRuntimeInstall = installs.wake
+export const subscribeManagedRuntimeInstalls = installs.subscribe
 
 function callHost<T>(
   subject: ManagedRuntimeInstallSubject,
@@ -188,22 +54,11 @@ function callHost<T>(
   )
 }
 
-async function startOperation(
-  subject: ManagedRuntimeInstallSubject,
-  method: 'managedRuntime.install' | 'managedRuntime.remove'
-): Promise<void> {
-  const entry = entryFor(subject)
-  const { generation } = entry
-  const state = await callHost<ManagedRuntimeInstallState>(subject, method, {})
-  // A reply that crossed a resubscribe is stale; the new subscription's snapshot governs.
-  if (entry.generation === generation) {
-    accept(entry, state, generation)
-  }
-}
-
 /** Starts, or joins, the host's install; rejects with the host's refusal. */
 export function installManagedRuntime(subject: ManagedRuntimeInstallSubject): Promise<void> {
-  return startOperation(subject, 'managedRuntime.install')
+  return installs.applyReply(subject, () =>
+    callHost<ManagedRuntimeInstallState>(subject, 'managedRuntime.install', {})
+  )
 }
 
 /** Resolves once the run has unwound; the subscription shows its outcome. */
@@ -216,12 +71,7 @@ export async function cancelManagedRuntimeInstall(
 
 /** Starts, or joins, the host's removal; it fails, keeping the files, while anything may run them. */
 export function removeManagedRuntime(subject: ManagedRuntimeInstallSubject): Promise<void> {
-  return startOperation(subject, 'managedRuntime.remove')
-}
-
-export function subscribeManagedRuntimeInstalls(listener: () => void): () => void {
-  listeners.add(listener)
-  return () => {
-    listeners.delete(listener)
-  }
+  return installs.applyReply(subject, () =>
+    callHost<ManagedRuntimeInstallState>(subject, 'managedRuntime.remove', {})
+  )
 }
diff --git a/src/renderer/src/runtime/revisioned-host-state-store.ts b/src/renderer/src/runtime/revisioned-host-state-store.ts
new file mode 100644
index 00000000000..8df9618d90c
--- /dev/null
+++ b/src/renderer/src/runtime/revisioned-host-state-store.ts
@@ -0,0 +1,181 @@
+import type { RuntimeRpcSubscriptionHandlers } from './runtime-rpc-subscribe'
+
+/**
+ * A host-owned state per subject, pushed by revision. While any surface observes a subject, one
+ * subscription carries the host's state, idle included, so another client's change shows up too;
+ * the last surface leaving ends it.
+ */
+
+export type RevisionedHostSnapshot<S> =
+  | { kind: 'unknown' }
+  /** No answer yet and the last read failed: says nothing about the host's state. */
+  | { kind: 'readFailed' }
+  | { kind: 'known'; state: S }
+
+type Entry<Subject, S> = {
+  subject: Subject
+  snapshot: RevisionedHostSnapshot<S>
+  observers: number
+  /** Bumped by every subscribe and every loss; a frame from another generation is stale. */
+  generation: number
+  /** The generation the shown state came from: revisions only order one subscription's frames. */
+  shownGeneration: number
+  stream: { unsubscribe: () => void } | null
+  retry: ReturnType<typeof setTimeout> | null
+  failures: number
+}
+
+const UNKNOWN = { kind: 'unknown' } as const
+
+export function createRevisionedHostStateStore<Subject, S extends { revision: number }>(options: {
+  key: (subject: Subject) => string
+  /** Subjects with the same host key and a different key answer for a restarted host. */
+  hostKey: (subject: Subject) => string
+  /** A full state on subscribe, then one per newer revision, until unsubscribed or lost. */
+  subscribe: (
+    subject: Subject,
+    handlers: RuntimeRpcSubscriptionHandlers
+  ) => Promise<{ unsubscribe: () => void }>
+}) {
+  const entries = new Map<string, Entry<Subject, S>>()
+  const listeners = new Set<() => void>()
+
+  const setSnapshot = (entry: Entry<Subject, S>, snapshot: RevisionedHostSnapshot<S>): void => {
+    entry.snapshot = snapshot
+    listeners.forEach((listener) => listener())
+  }
+
+  const entryFor = (subject: Subject): Entry<Subject, S> => {
+    const key = options.key(subject)
+    let entry = entries.get(key)
+    if (!entry) {
+      // A restarted host runtime answers under a new key; the old one's answer is stale.
+      for (const [otherKey, other] of entries) {
+        if (other.observers === 0 && options.hostKey(other.subject) === options.hostKey(subject)) {
+          entries.delete(otherKey)
+        }
+      }
+      entry = {
+        subject,
+        snapshot: UNKNOWN,
+        observers: 0,
+        generation: 0,
+        shownGeneration: 0,
+        stream: null,
+        retry: null,
+        failures: 0
+      }
+      entries.set(key, entry)
+    }
+    return entry
+  }
+
+  const accept = (entry: Entry<Subject, S>, state: S, generation: number): void => {
+    // A new subscription may reach a restarted host whose revisions start again at 0.
+    if (
+      entry.snapshot.kind !== 'known' ||
+      generation !== entry.shownGeneration ||
+      entry.snapshot.state.revision < state.revision
+    ) {
+      entry.shownGeneration = generation
+      setSnapshot(entry, { kind: 'known', state })
+    }
+  }
+
+  const isState = (value: unknown): value is S =>
+    typeof value === 'object' &&
+    value !== null &&
+    'revision' in value &&
+    typeof value.revision === 'number'
+
+  const close = (entry: Entry<Subject, S>): void => {
+    entry.generation += 1
+    entry.stream?.unsubscribe()
+    entry.stream = null
+    if (entry.retry) {
+      clearTimeout(entry.retry)
+      entry.retry = null
+    }
+  }
+
+  const open = (entry: Entry<Subject, S>): void => {
+    close(entry)
+    const { generation } = entry
+    const current = (): boolean => entry.observers > 0 && entry.generation === generation
+    const lost = (): void => {
+      if (!current()) {
+        return
+      }
+      close(entry)
+      // A known answer stays through a blip; only a first read failing changes what is shown.
+      if (entry.snapshot.kind !== 'known') {
+        setSnapshot(entry, { kind: 'readFailed' })
+      }
+      entry.failures += 1
+      const delay = Math.min(30_000, 1000 * 2 ** (entry.failures - 1))
+      entry.retry = setTimeout(() => open(entry), delay)
+    }
+    void options
+      .subscribe(entry.subject, {
+        onEvent: (result) => {
+          if (current() && isState(result)) {
+            entry.failures = 0
+            accept(entry, result, generation)
+          }
+        },
+        onError: lost,
+        onClose: lost
+      })
+      .then((opened) => {
+        if (current()) {
+          entry.stream = opened
+        } else {
+          opened.unsubscribe()
+        }
+      }, lost)
+  }
+
+  return {
+    read: (subject: Subject): RevisionedHostSnapshot<S> =>
+      entries.get(options.key(subject))?.snapshot ?? UNKNOWN,
+    /** Subscribes while at least one shown surface observes `subject`. Returns the release. */
+    observe: (subject: Subject): (() => void) => {
+      const entry = entryFor(subject)
+      entry.observers += 1
+      if (entry.observers === 1) {
+        entry.failures = 0
+        open(entry)
+      }
+      return () => {
+        entry.observers -= 1
+        if (entry.observers === 0) {
+          close(entry)
+        }
+      }
+    },
+    /** Resubscribes a lost stream at once, e.g. when the host answers again after an outage. */
+    wake: (subject: Subject): void => {
+      const entry = entries.get(options.key(subject))
+      if (entry?.retry) {
+        entry.failures = 0
+        open(entry)
+      }
+    },
+    /** Shows an action's reply, ordered by revision with the subscription's frames. */
+    applyReply: async (subject: Subject, request: () => Promise<S>): Promise<void> => {
+      const entry = entryFor(subject)
+      const { generation } = entry
+      const state = await request()
+      // A reply that crossed a resubscribe is stale; the new subscription's snapshot governs.
+      if (entry.generation === generation) {
+        accept(entry, state, generation)
+      }
+    },
+    subscribe: (listener: () => void): (() => void) => {
+      listeners.add(listener)
+      return () => {
+        listeners.delete(listener)
+      }
+    }
+  }
+}
diff --git a/src/renderer/src/runtime/runtime-antigravity-accounts-client.ts b/src/renderer/src/runtime/runtime-antigravity-accounts-client.ts
index c115770c494..215a3a639d2 100644
--- a/src/renderer/src/runtime/runtime-antigravity-accounts-client.ts
+++ b/src/renderer/src/runtime/runtime-antigravity-accounts-client.ts
@@ -2,9 +2,13 @@ import type {
   AntigravityAccountState,
   AntigravityAccountTarget
 } from '../../../shared/antigravity-account-types'
-import { ANTIGRAVITY_ACCOUNTS_RUNTIME_CAPABILITY } from '../../../shared/account-runtime-capabilities'
+import {
+  ANTIGRAVITY_ACCOUNTS_RUNTIME_CAPABILITY,
+  ANTIGRAVITY_CHAT_SIGN_IN_RUNTIME_CAPABILITY
+} from '../../../shared/account-runtime-capabilities'
 import type { RuntimeClientTarget } from '../../../shared/runtime-client-target'
 import { assertRuntimeEnvironmentCapability, callRuntimeRpc } from './runtime-rpc-client'
+import { subscribeRuntimeRpc, type RuntimeRpcSubscriptionHandlers } from './runtime-rpc-subscribe'
 
 export async function callAntigravityAccounts(
   owner: RuntimeClientTarget,
@@ -26,3 +30,33 @@ export async function callAntigravityAccounts(
     { timeoutMs: 20_000 }
   )
 }
+
+async function assertChatSignInHost(owner: RuntimeClientTarget): Promise<void> {
+  if (owner.kind === 'environment') {
+    await assertRuntimeEnvironmentCapability(
+      owner.environmentId,
+      ANTIGRAVITY_CHAT_SIGN_IN_RUNTIME_CAPABILITY,
+      'This execution host does not support Antigravity chat sign-in yet. Update Orca on that host.'
+    )
+  }
+}
+
+export async function callAntigravityChatSignIn<TResult>(
+  owner: RuntimeClientTarget,
+  action: 'Start' | 'Cancel' | 'Complete',
+  params?: { flowId: string; callbackUrl?: string }
+): Promise<TResult> {
+  await assertChatSignInHost(owner)
+  return callRuntimeRpc(owner, `accounts.antigravityChatSignIn${action}`, params, {
+    timeoutMs: 20_000
+  })
+}
+
+/** The host's sign-in status: a snapshot, then one frame per newer revision. */
+export async function subscribeAntigravityChatSignIn(
+  owner: RuntimeClientTarget,
+  handlers: RuntimeRpcSubscriptionHandlers
+): Promise<{ unsubscribe: () => void }> {
+  await assertChatSignInHost(owner)
+  return subscribeRuntimeRpc(owner, 'accounts.antigravityChatSignInSubscribe', null, handlers)
+}
diff --git a/src/shared/agent-session-availability.test.ts b/src/shared/agent-session-availability.test.ts
index 2c81374072d..446aeb393c6 100644
--- a/src/shared/agent-session-availability.test.ts
+++ b/src/shared/agent-session-availability.test.ts
@@ -42,4 +42,9 @@ describe("the host's sign-in and CLI verdict", () => {
       )
     )
   })
+  it('sends Antigravity to its sign-in in Settings', () => {
+    expect(
+      agentSessionFailureSentence({ kind: 'notSignedIn' }, 'row', { agentName: 'antigravity' })
+    ).toBe(AGENT_SESSION_FAILURE_COPY.antigravityNotSignedIn)
+  })
 })
diff --git a/src/shared/agent-session-availability.ts b/src/shared/agent-session-availability.ts
index 78a072d0c25..e2e7496b54a 100644
--- a/src/shared/agent-session-availability.ts
+++ b/src/shared/agent-session-availability.ts
@@ -36,9 +36,11 @@ export function agentSessionSignInCopyId(provider: string, account?: AgentSessio
       ? account === 'managed'
         ? 'codexManagedNotSignedIn'
         : 'codexSystemNotSignedIn'
-      : signIn?.agent === 'pi'
-        ? 'interactiveAgentNotSignedIn'
-        : signIn?.loginCommand.length
-          ? 'agentCommandNotSignedIn'
-          : 'agentNotSignedIn'
+      : signIn?.agent === 'antigravity'
+        ? 'antigravityNotSignedIn'
+        : signIn?.agent === 'pi'
+          ? 'interactiveAgentNotSignedIn'
+          : signIn?.loginCommand.length
+            ? 'agentCommandNotSignedIn'
+            : 'agentNotSignedIn'
 }
diff --git a/src/shared/agent-session-failure-copy.ts b/src/shared/agent-session-failure-copy.ts
index 83f80a1f390..bd7523db85c 100644
--- a/src/shared/agent-session-failure-copy.ts
+++ b/src/shared/agent-session-failure-copy.ts
@@ -46,6 +46,8 @@ export const AGENT_SESSION_FAILURE_COPY = {
   codexSystemNotSignedIn: "Codex isn't signed in. Run `{{loginCommand}}`.",
   codexManagedNotSignedIn:
     "This Codex account isn't signed in. Sign in again in Codex Accounts settings.",
+  antigravityNotSignedIn:
+    "Antigravity isn't signed in. Sign in under Settings → Accounts → Antigravity.",
   agentCommandNotSignedIn:
     'Sign in to {{agent}} with `{{loginCommand}}` on the computer running this chat.',
   interactiveAgentNotSignedIn: