diff --git a/src/hooks/legacy-plugin-toast/auto-migrate-runner.ts b/src/hooks/legacy-plugin-toast/auto-migrate-runner.ts
new file mode 100644
index 000000000..c77fea2b9
--- /dev/null
+++ b/src/hooks/legacy-plugin-toast/auto-migrate-runner.ts
@@ -0,0 +1,2 @@
+export { autoMigrateLegacyPluginEntry } from "./auto-migrate"
+export type { MigrationResult } from "./auto-migrate"
diff --git a/src/hooks/legacy-plugin-toast/auto-migrate.ts b/src/hooks/legacy-plugin-toast/auto-migrate.ts
index 34bc4bbc0..a33cf8ac9 100644
--- a/src/hooks/legacy-plugin-toast/auto-migrate.ts
+++ b/src/hooks/legacy-plugin-toast/auto-migrate.ts
@@ -1,9 +1,10 @@
-import { existsSync, readFileSync, writeFileSync } from "node:fs"
+import { existsSync, readFileSync } from "node:fs"
 import { join } from "node:path"
 
 import { parseJsoncSafe } from "../../shared/jsonc-parser"
 import { getOpenCodeConfigPaths } from "../../shared/opencode-config-dir"
 import { LEGACY_PLUGIN_NAME, PLUGIN_NAME } from "../../shared/plugin-identity"
+import { migrateLegacyPluginEntry } from "./plugin-entry-migrator"
 
 export interface MigrationResult {
   migrated: boolean
@@ -63,27 +64,15 @@ export function autoMigrateLegacyPluginEntry(overrideConfigDir?: string): Migrat
     const hasCanonical = plugins.some(isCanonicalEntry)
     const from = legacyEntries[0]
     const to = toLegacyCanonical(from)
+    const migrated = migrateLegacyPluginEntry(configPath)
+    if (!migrated) return { migrated: false, from: null, to: null, configPath }
 
-    const normalized = hasCanonical
-      ? plugins.filter((p) => !isLegacyEntry(p))
-      : plugins.map((p) => (isLegacyEntry(p) ? toLegacyCanonical(p) : p))
-
-    const isJsonc = configPath.endsWith(".jsonc")
-    if (isJsonc) {
-      const pluginArrayRegex = /((?:"plugin"|plugin)\s*:\s*)\[([\s\S]*?)\]/
-      const match = content.match(pluginArrayRegex)
-      if (match) {
-        const formattedPlugins = normalized.map((p) => `"${p}"`).join(",\n    ")
-        const newContent = content.replace(pluginArrayRegex, `$1[\n    ${formattedPlugins}\n  ]`)
-        writeFileSync(configPath, newContent)
-        return { migrated: true, from, to, configPath }
-      }
+    return {
+      migrated: true,
+      from,
+      to: hasCanonical ? PLUGIN_NAME : to,
+      configPath,
     }
-
-    const parsed = JSON.parse(content) as Record<string, unknown>
-    parsed.plugin = normalized
-    writeFileSync(configPath, JSON.stringify(parsed, null, 2) + "\n")
-    return { migrated: true, from, to, configPath }
   } catch {
     return { migrated: false, from: null, to: null, configPath }
   }
diff --git a/src/hooks/legacy-plugin-toast/hook.test.ts b/src/hooks/legacy-plugin-toast/hook.test.ts
index 490908429..c355587fc 100644
--- a/src/hooks/legacy-plugin-toast/hook.test.ts
+++ b/src/hooks/legacy-plugin-toast/hook.test.ts
@@ -1,5 +1,5 @@
 import { afterAll, beforeEach, describe, expect, it, mock } from "bun:test"
-import type { MigrationResult } from "./auto-migrate"
+import type { MigrationResult } from "./auto-migrate-runner"
 
 const mockCheckForLegacyPluginEntry = mock(() => ({
   hasLegacyEntry: false,
@@ -26,7 +26,7 @@ mock.module("../../shared/logger", () => ({
   log: mockLog,
 }))
 
-mock.module("./auto-migrate", () => ({
+mock.module("./auto-migrate-runner", () => ({
   autoMigrateLegacyPluginEntry: mockAutoMigrate,
 }))
 
diff --git a/src/hooks/legacy-plugin-toast/hook.ts b/src/hooks/legacy-plugin-toast/hook.ts
index 4d6f55918..69f971f25 100644
--- a/src/hooks/legacy-plugin-toast/hook.ts
+++ b/src/hooks/legacy-plugin-toast/hook.ts
@@ -3,7 +3,7 @@ import type { PluginInput } from "@opencode-ai/plugin"
 import { checkForLegacyPluginEntry } from "../../shared/legacy-plugin-warning"
 import { log } from "../../shared/logger"
 import { LEGACY_PLUGIN_NAME, PLUGIN_NAME } from "../../shared/plugin-identity"
-import { autoMigrateLegacyPluginEntry } from "./auto-migrate"
+import { autoMigrateLegacyPluginEntry } from "./auto-migrate-runner"
 
 export function createLegacyPluginToastHook(ctx: PluginInput) {
   let fired = false
diff --git a/src/hooks/legacy-plugin-toast/plugin-entry-migrator.ts b/src/hooks/legacy-plugin-toast/plugin-entry-migrator.ts
new file mode 100644
index 000000000..27aaaedc1
--- /dev/null
+++ b/src/hooks/legacy-plugin-toast/plugin-entry-migrator.ts
@@ -0,0 +1 @@
+export { migrateLegacyPluginEntry } from "../../shared/migrate-legacy-plugin-entry"
diff --git a/src/shared/log-legacy-plugin-startup-warning.test.ts b/src/shared/log-legacy-plugin-startup-warning.test.ts
index 4acd38385..0b288a461 100644
--- a/src/shared/log-legacy-plugin-startup-warning.test.ts
+++ b/src/shared/log-legacy-plugin-startup-warning.test.ts
@@ -26,7 +26,7 @@ mock.module("./logger", () => ({
   log: mockLog,
 }))
 
-mock.module("./migrate-legacy-plugin-entry", () => ({
+mock.module("./plugin-entry-migrator", () => ({
   migrateLegacyPluginEntry: mockMigrateLegacyPluginEntry,
 }))
 
diff --git a/src/shared/log-legacy-plugin-startup-warning.ts b/src/shared/log-legacy-plugin-startup-warning.ts
index dc6505a5f..1ff3c7c19 100644
--- a/src/shared/log-legacy-plugin-startup-warning.ts
+++ b/src/shared/log-legacy-plugin-startup-warning.ts
@@ -1,6 +1,6 @@
 import { checkForLegacyPluginEntry } from "./legacy-plugin-warning"
 import { log } from "./logger"
-import { migrateLegacyPluginEntry } from "./migrate-legacy-plugin-entry"
+import { migrateLegacyPluginEntry } from "./plugin-entry-migrator"
 import { LEGACY_PLUGIN_NAME, PLUGIN_NAME } from "./plugin-identity"
 
 function toCanonicalEntry(entry: string): string {
diff --git a/src/shared/plugin-entry-migrator.ts b/src/shared/plugin-entry-migrator.ts
new file mode 100644
index 000000000..50cc7c1a1
--- /dev/null
+++ b/src/shared/plugin-entry-migrator.ts
@@ -0,0 +1 @@
+export { migrateLegacyPluginEntry } from "./migrate-legacy-plugin-entry"