diff --git a/src/hooks/auto-update-checker/hook/background-update-check.ts b/src/hooks/auto-update-checker/hook/background-update-check.ts
index 5b092cfd8..3ef3a3d7d 100644
--- a/src/hooks/auto-update-checker/hook/background-update-check.ts
+++ b/src/hooks/auto-update-checker/hook/background-update-check.ts
@@ -1,6 +1,6 @@
 import type { PluginInput } from "@opencode-ai/plugin"
-import { existsSync } from "node:fs"
-import { join } from "node:path"
+import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs"
+import { dirname, join } from "node:path"
 import { runBunInstallWithDetails } from "../../../cli/config-manager"
 import { log } from "../../../shared/logger"
 import { getOpenCodeCacheDir, getOpenCodeConfigPaths } from "../../../shared"
@@ -12,6 +12,10 @@ import { showAutoUpdatedToast, showUpdateAvailableToast } from "./update-toasts"
 
 type BackgroundUpdateCheckDeps = {
   existsSync: typeof existsSync
+  mkdirSync: typeof mkdirSync
+  readFileSync: typeof readFileSync
+  writeFileSync: typeof writeFileSync
+  dirname: typeof dirname
   join: typeof join
   runBunInstallWithDetails: typeof runBunInstallWithDetails
   log: typeof log
@@ -25,6 +29,12 @@ type BackgroundUpdateCheckDeps = {
   syncCachePackageJsonToIntent: typeof syncCachePackageJsonToIntent
   showUpdateAvailableToast: typeof showUpdateAvailableToast
   showAutoUpdatedToast: typeof showAutoUpdatedToast
+  now: () => number
+}
+
+type LastUpdatedMarker = {
+  readonly version: string
+  readonly updatedAt: number
 }
 
 type BackgroundUpdateCheckRunner = (
@@ -39,6 +49,10 @@ function getCacheWorkspaceDir(deps: BackgroundUpdateCheckDeps): string {
 
 const defaultDeps: BackgroundUpdateCheckDeps = {
   existsSync,
+  mkdirSync,
+  readFileSync,
+  writeFileSync,
+  dirname,
   join,
   runBunInstallWithDetails,
   log,
@@ -52,12 +66,54 @@ const defaultDeps: BackgroundUpdateCheckDeps = {
   syncCachePackageJsonToIntent,
   showUpdateAvailableToast,
   showAutoUpdatedToast,
+  now: () => Date.now(),
 }
 
+const LAST_UPDATED_MARKER_FILE = ".last-updated"
+const RECENT_INSTALL_WINDOW_MS = 5 * 60 * 1000
+
 function getPinnedVersionToastMessage(latestVersion: string): string {
   return `Update available: ${latestVersion} (version pinned, update manually)`
 }
 
+function getLastUpdatedMarkerPath(deps: BackgroundUpdateCheckDeps): string {
+  return deps.join(deps.getOpenCodeCacheDir(), LAST_UPDATED_MARKER_FILE)
+}
+
+function parseLastUpdatedMarker(rawMarker: string): LastUpdatedMarker | null {
+  const marker: unknown = JSON.parse(rawMarker)
+  if (typeof marker !== "object" || marker === null) return null
+  if (!("version" in marker) || typeof marker.version !== "string") return null
+  if (!("updatedAt" in marker) || typeof marker.updatedAt !== "number") return null
+  return { version: marker.version, updatedAt: marker.updatedAt }
+}
+
+function wasRecentlyInstalled(version: string, deps: BackgroundUpdateCheckDeps): boolean {
+  try {
+    const markerPath = getLastUpdatedMarkerPath(deps)
+    if (!deps.existsSync(markerPath)) return false
+
+    const marker = parseLastUpdatedMarker(deps.readFileSync(markerPath, "utf-8"))
+    if (!marker) return false
+    if (marker.version !== version) return false
+
+    return deps.now() - marker.updatedAt < RECENT_INSTALL_WINDOW_MS
+  } catch (err) {
+    deps.log("[auto-update-checker] Failed to read last update marker:", err)
+    return false
+  }
+}
+
+function writeLastUpdatedMarker(version: string, deps: BackgroundUpdateCheckDeps): void {
+  try {
+    const markerPath = getLastUpdatedMarkerPath(deps)
+    deps.mkdirSync(deps.dirname(markerPath), { recursive: true })
+    deps.writeFileSync(markerPath, JSON.stringify({ version, updatedAt: deps.now() }, null, 2))
+  } catch (err) {
+    deps.log("[auto-update-checker] Failed to write last update marker:", err)
+  }
+}
+
 /**
  * Resolves the active install workspace.
  * Same logic as doctor check: prefer config-dir if installed, fall back to cache-dir.
@@ -153,6 +209,11 @@ export function createBackgroundUpdateCheckRunner(
       return
     }
 
+    if (wasRecentlyInstalled(latestVersion, deps)) {
+      deps.log(`[auto-update-checker] Skipping update check; ${latestVersion} was installed recently`)
+      return
+    }
+
     deps.log(`[auto-update-checker] Update available (${channel}): ${currentVersion} → ${latestVersion}`)
 
     if (!autoUpdate) {
@@ -186,6 +247,7 @@ export function createBackgroundUpdateCheckRunner(
         return
       }
 
+      writeLastUpdatedMarker(latestVersion, deps)
       await deps.showAutoUpdatedToast(ctx, currentVersion, latestVersion)
       deps.log(`[auto-update-checker] Update installed: ${currentVersion} → ${latestVersion}`)
       return
diff --git a/src/hooks/zauc-mocks-ws/workspace-resolution.test.ts b/src/hooks/zauc-mocks-ws/workspace-resolution.test.ts
index c9171289d..8e3bc0785 100644
--- a/src/hooks/zauc-mocks-ws/workspace-resolution.test.ts
+++ b/src/hooks/zauc-mocks-ws/workspace-resolution.test.ts
@@ -1,6 +1,6 @@
 import type { PluginInput } from "@opencode-ai/plugin"
 import { afterEach, beforeEach, describe, expect, it, mock } from "bun:test"
-import { existsSync, mkdirSync, rmSync, writeFileSync } from "node:fs"
+import { existsSync, mkdirSync, readFileSync, rmSync, writeFileSync } from "node:fs"
 import { join } from "node:path"
 
 import type { PluginEntryInfo } from "../auto-update-checker/checker"
@@ -191,4 +191,25 @@ describe("workspace resolution", () => {
     expect(mockRunBunInstallWithDetails.mock.calls[0]?.[0]?.workspaceDir).toBe(TEST_CONFIG_DIR)
     expect(mockRunBunInstallWithDetails.mock.calls[1]?.[0]?.workspaceDir).toBe(TEST_CACHE_WORKSPACE_DIR)
   })
+
+  it("#given same version was just installed #when next startup checks again #then it skips reinstall loop", async () => {
+    // #given
+    const firstRun = await createRunner()
+    mkdirSync(TEST_CACHE_WORKSPACE_DIR, { recursive: true })
+    writeFileSync(join(TEST_CACHE_WORKSPACE_DIR, "package.json"), JSON.stringify({ dependencies: { [PACKAGE_NAME]: "3.4.0" } }, null, 2))
+
+    // #when
+    await firstRun(mockCtx, true, getToastMessage)
+    const markerPath = join(TEST_CACHE_DIR, ".last-updated")
+    const secondRun = await createRunner()
+    await secondRun(mockCtx, true, getToastMessage)
+
+    // #then
+    expect(readFileSync(markerPath, "utf-8")).toContain('"version": "3.5.0"')
+    expect(mockRunBunInstallWithDetails).toHaveBeenCalledTimes(1)
+    expect(mockSyncCachePackageJsonToIntent).toHaveBeenCalledTimes(1)
+    expect(mockInvalidatePackage).toHaveBeenCalledTimes(1)
+    expect(mockShowAutoUpdatedToast).toHaveBeenCalledTimes(1)
+    expect(mockShowUpdateAvailableToast).not.toHaveBeenCalled()
+  })
 })