fix(tui): sync model preferences across clients

packages/tui/src/context/local.tsx

@@ -12,8 +12,10 @@ import { readJson, writeJsonAtomic } from "../util/persistence"
 import {
   createModelPreferenceRepository,
   cycleModelVariant,
+  favoriteModels,
   modelPreferenceKey,
   normalizeModelVariant,
+  recentModels,
   type ModelPreference,
   type ModelPreferenceModel,
 } from "../model-preference"
@@ -32,19 +34,6 @@ export function parseModel(model: string) {
   }
 }
 
-export function recentModels(model: ModelPreferenceModel, recent: ModelPreferenceModel[]) {
-  const seen = new Set<string>()
-  return [model, ...recent]
-    .filter((item) => {
-      const key = modelPreferenceKey(item)
-      if (seen.has(key)) return false
-      seen.add(key)
-      return true
-    })
-    .slice(0, 10)
-    .map((item) => ({ providerID: item.providerID, modelID: item.modelID }))
-}
-
 export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
   name: "Local",
   init: () => {
@@ -151,37 +140,16 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
       const pendingSelectionCommits = new Map<string, string>()
       const selectionKey = (value: ModelSelection) =>
         `${modelPreferenceKey(value)}:${normalizeModelVariant(value.variant) ?? "default"}`
-      const saveState = {
-        pending: false,
-      }
-
-      function savePreferences() {
-        if (!preferences.ready) {
-          saveState.pending = true
-          return
-        }
-        saveState.pending = false
-        void repository
-          .patch({
-            recent: preferences.recent,
-            favorite: preferences.favorite,
-            variant: preferences.variant,
-          })
-          .catch(() => undefined)
-      }
-
-      repository
-        .load()
-        .then((value) => {
+      function applyPreferences(value: ModelPreference) {
+        batch(() => {
           setPreferences("recent", value.recent)
           setPreferences("favorite", value.favorite)
           setPreferences("variant", value.variant)
-        })
-        .catch(() => {})
-        .finally(() => {
           setPreferences("ready", true)
-          if (saveState.pending) savePreferences()
         })
+      }
+
+      onCleanup(repository.subscribe(applyPreferences))
 
       const fallbackModel = createMemo(() => {
         if (args.model) {
@@ -389,7 +357,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
           if (!next) return
           if (!selectModel({ ...next })) return
           setPreferences("recent", recentModels(next, preferences.recent))
-          savePreferences()
+          void repository.addRecent(next).catch(() => undefined)
         },
         set(model: { providerID: string; modelID: string }, options?: { recent?: boolean }) {
           batch(() => {
@@ -397,7 +365,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
             if (!selectModel(model)) return
             if (options?.recent) {
               setPreferences("recent", recentModels(model, preferences.recent))
-              savePreferences()
+              void repository.addRecent(model).catch(() => undefined)
             }
           })
         },
@@ -407,14 +375,8 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
             const exists = preferences.favorite.some(
               (x) => x.providerID === model.providerID && x.modelID === model.modelID,
             )
-            const next = exists
-              ? preferences.favorite.filter((x) => x.providerID !== model.providerID || x.modelID !== model.modelID)
-              : [model, ...preferences.favorite]
-            setPreferences(
-              "favorite",
-              next.map((x) => ({ providerID: x.providerID, modelID: x.modelID })),
-            )
-            savePreferences()
+            setPreferences("favorite", favoriteModels(model, preferences.favorite, !exists))
+            void repository.setFavorite(model, !exists).catch(() => undefined)
           })
         },
         variant: {
@@ -439,7 +401,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
               setSessionDraft(route.data.sessionID, { ...m, variant: normalizeModelVariant(value) })
             }
             setPreferences("variant", modelPreferenceKey(m), normalizeModelVariant(value))
-            savePreferences()
+            void repository.saveVariant(m, value).catch(() => undefined)
           },
           cycle() {
             const variants = this.list()

packages/tui/src/model-preference.ts

@@ -1,5 +1,7 @@
 import { readJson, writeJsonAtomic } from "./util/persistence"
 import { isRecord } from "./util/record"
+import { watch } from "node:fs"
+import path from "node:path"
 
 export type ModelPreferenceModel = {
   providerID: string
@@ -43,6 +45,24 @@ export function modelPreferenceKey(model: ModelPreferenceModel) {
   return `${model.providerID}/${model.modelID}`
 }
 
+export function recentModels(model: ModelPreferenceModel, recent: ModelPreferenceModel[]) {
+  const seen = new Set<string>()
+  return [model, ...recent]
+    .filter((item) => {
+      const key = modelPreferenceKey(item)
+      if (seen.has(key)) return false
+      seen.add(key)
+      return true
+    })
+    .slice(0, 10)
+    .map((item) => ({ providerID: item.providerID, modelID: item.modelID }))
+}
+
+export function favoriteModels(model: ModelPreferenceModel, favorite: ModelPreferenceModel[], enabled: boolean) {
+  const current = favorite.filter((item) => modelPreferenceKey(item) !== modelPreferenceKey(model))
+  return enabled ? [model, ...current] : current
+}
+
 export function cycleModelVariant(current: string | undefined, variants: string[]) {
   const named = variants.filter((variant) => variant !== "default")
   if (named.length === 0) return undefined
@@ -80,32 +100,78 @@ function patch(value: Partial<ModelPreference>) {
 }
 
 export function createModelPreferenceRepository(filePath: string) {
-  const state = {
-    pending: Promise.resolve(),
-  }
+  let pending = Promise.resolve()
+  let revision = 0
+  let watcher: ReturnType<typeof watch> | undefined
+  let reload: ReturnType<typeof setTimeout> | undefined
+  const listeners = new Set<(value: ModelPreference) => void>()
   const read = () =>
     readJson<unknown>(filePath)
       .then(decodeModelPreference)
       .catch(() => decodeModelPreference(undefined))
 
   function update(change: (current: ModelPreference) => Partial<ModelPreference>) {
-    const result = state.pending.then(async () => {
-      const current = await read()
-      const next = { ...current, ...patch(change(preference(current))) }
-      await writeJsonAtomic(filePath, next)
+    const result = pending.then(async () => {
+      const { Flock } = await import("@opencode-ai/util/flock")
+      return Flock.withLock(
+        filePath,
+        async () => {
+          const current = await read()
+          const next = { ...current, ...patch(change(preference(current))) }
+          await writeJsonAtomic(filePath, next)
+        },
+        { dir: path.join(path.dirname(filePath), "locks") },
+      )
     })
-    state.pending = result.catch(() => undefined)
+    pending = result.then(
+      () => undefined,
+      () => undefined,
+    )
     return result
   }
 
   function load() {
-    return state.pending.then(read).then(preference)
+    return pending.then(read).then(preference)
+  }
+
+  async function refresh() {
+    const current = ++revision
+    const value = await load()
+    if (current !== revision) return
+    listeners.forEach((listener) => listener(value))
   }
 
   return {
     load,
-    patch(value: Partial<ModelPreference>) {
-      return update(() => value)
+    addRecent(model: ModelPreferenceModel) {
+      return update((current) => ({ recent: recentModels(model, current.recent) }))
+    },
+    setFavorite(model: ModelPreferenceModel, enabled: boolean) {
+      return update((current) => ({ favorite: favoriteModels(model, current.favorite, enabled) }))
+    },
+    subscribe(listener: (value: ModelPreference) => void) {
+      listeners.add(listener)
+      void refresh()
+      if (!watcher) {
+        watcher = watch(path.dirname(filePath), (_event, filename) => {
+          const changed = filename?.toString()
+          const name = path.basename(filePath)
+          if (changed !== undefined && changed !== name && !changed.startsWith(name + ".")) return
+          clearTimeout(reload)
+          reload = setTimeout(() => void refresh(), 50)
+        })
+        watcher.on("error", () => {
+          watcher?.close()
+          watcher = undefined
+        })
+      }
+      return () => {
+        listeners.delete(listener)
+        if (listeners.size > 0) return
+        clearTimeout(reload)
+        watcher?.close()
+        watcher = undefined
+      }
     },
     async resolveVariant(model: ModelPreferenceModel) {
       return (await load()).variant[modelPreferenceKey(model)]

packages/tui/test/context/local.test.ts

@@ -1,5 +1,6 @@
 import { expect, test } from "bun:test"
-import { parseModel, recentModels } from "../../src/context/local"
+import { parseModel } from "../../src/context/local"
+import { recentModels } from "../../src/model-preference"
 
 test("parses model IDs containing slashes", () => {
   expect(parseModel("provider/family/model")).toEqual({

packages/tui/test/model-preference.test.ts

@@ -19,7 +19,7 @@ test("repairs known model preferences and preserves unrelated fields", () => {
   })
 })
 
-test("atomically serializes patches and variant updates", async () => {
+test("atomically serializes model preference updates", async () => {
   await using tmp = await tmpdir()
   const file = path.join(tmp.path, "model.json")
   await Bun.write(file, JSON.stringify({ unrelated: "keep", favorite: [], variant: {} }))
@@ -28,7 +28,7 @@ test("atomically serializes patches and variant updates", async () => {
   const anthropic = { providerID: "anthropic", modelID: "claude/sonnet" }
 
   await Promise.all([
-    repository.patch({ recent: [openai] }),
+    repository.addRecent(openai),
     repository.saveVariant(openai, "high"),
     repository.saveVariant(anthropic, "low"),
   ])
@@ -43,3 +43,47 @@ test("atomically serializes patches and variant updates", async () => {
   expect(await repository.resolveVariant(openai)).toBeUndefined()
   expect((await Bun.file(file).json()).variant).toEqual({ "anthropic/claude/sonnet": "low" })
 })
+
+test("serializes updates across repositories", async () => {
+  await using tmp = await tmpdir()
+  const file = path.join(tmp.path, "model.json")
+  await Bun.write(file, JSON.stringify({ recent: [], favorite: [], variant: {} }))
+  const first = createModelPreferenceRepository(file)
+  const second = createModelPreferenceRepository(file)
+  const openai = { providerID: "openai", modelID: "gpt-5" }
+  const anthropic = { providerID: "anthropic", modelID: "claude-sonnet" }
+
+  await Promise.all([first.setFavorite(openai, true), second.addRecent(anthropic), second.saveVariant(openai, "high")])
+
+  expect(await first.load()).toEqual({
+    recent: [anthropic],
+    favorite: [openai],
+    variant: { "openai/gpt-5": "high" },
+  })
+})
+
+test("subscribes to updates from another repository", async () => {
+  await using tmp = await tmpdir()
+  const file = path.join(tmp.path, "model.json")
+  await Bun.write(file, JSON.stringify({ recent: [], favorite: [], variant: {} }))
+  const first = createModelPreferenceRepository(file)
+  const second = createModelPreferenceRepository(file)
+  const openai = { providerID: "openai", modelID: "gpt-5" }
+  const changed = Promise.withResolvers<void>()
+  const unsubscribe = first.subscribe((value) => {
+    if (value.favorite.some((item) => item.providerID === openai.providerID && item.modelID === openai.modelID))
+      changed.resolve()
+  })
+
+  try {
+    await second.setFavorite(openai, true)
+    await Promise.race([
+      changed.promise,
+      Bun.sleep(2_000).then(() => {
+        throw new Error("timed out waiting for model preference update")
+      }),
+    ])
+  } finally {
+    unsubscribe()
+  }
+})