diff --git a/packages/opencode/src/provider/auth-service.ts b/packages/opencode/src/provider/auth-service.ts
index a97ce1840c..a49b92f52d 100644
--- a/packages/opencode/src/provider/auth-service.ts
+++ b/packages/opencode/src/provider/auth-service.ts
@@ -5,19 +5,10 @@ import { filter, fromEntries, map, mapValues, pipe } from "remeda"
 import type { AuthOuathResult } from "@opencode-ai/plugin"
 import { NamedError } from "@opencode-ai/util/error"
 import * as Auth from "@/auth/service"
+import * as ScopedState from "@/util/scoped-state"
 import { ProviderID } from "./schema"
 import z from "zod"
 
-const state = Instance.state(async () => {
-  const methods = pipe(
-    await Plugin.list(),
-    filter((x) => x.auth?.provider !== undefined),
-    map((x) => [x.auth!.provider, x.auth!] as const),
-    fromEntries(),
-  )
-  return { methods, pending: {} as Record<string, AuthOuathResult> }
-})
-
 export type Method = {
   type: "oauth" | "api"
   label: string
@@ -71,10 +62,23 @@ export class ProviderAuthService extends ServiceMap.Service<ProviderAuthService,
     ProviderAuthService,
     Effect.gen(function* () {
       const auth = yield* Auth.AuthService
+      const state = yield* ScopedState.make({
+        root: () => Instance.directory,
+        lookup: () =>
+          Effect.promise(async () => {
+            const methods = pipe(
+              await Plugin.list(),
+              filter((x) => x.auth?.provider !== undefined),
+              map((x) => [x.auth!.provider, x.auth!] as const),
+              fromEntries(),
+            )
+            return { methods, pending: {} as Record<string, AuthOuathResult> }
+          }),
+      })
 
       const methods = Effect.fn("ProviderAuthService.methods")(() =>
-        Effect.promise(() =>
-          state().then((x) =>
+        ScopedState.get(state).pipe(
+          Effect.map((x) =>
             mapValues(x.methods, (y) =>
               y.methods.map(
                 (z): Method => ({
@@ -91,15 +95,11 @@ export class ProviderAuthService extends ServiceMap.Service<ProviderAuthService,
         providerID: ProviderID
         method: number
       }) {
-        const item = yield* Effect.promise(() => state().then((x) => x.methods[input.providerID]))
+        const item = (yield* ScopedState.get(state)).methods[input.providerID]
         const method = item.methods[input.method]
         if (method.type !== "oauth") return
         const result = yield* Effect.promise(() => method.authorize())
-        yield* Effect.promise(() =>
-          state().then((x) => {
-            x.pending[input.providerID] = result
-          }),
-        )
+        ;(yield* ScopedState.get(state)).pending[input.providerID] = result
         return {
           url: result.url,
           method: result.method,
@@ -112,7 +112,7 @@ export class ProviderAuthService extends ServiceMap.Service<ProviderAuthService,
         method: number
         code?: string
       }) {
-        const match = yield* Effect.promise(() => state().then((x) => x.pending[input.providerID]))
+        const match = (yield* ScopedState.get(state)).pending[input.providerID]
         if (!match) return yield* Effect.fail(new OauthMissing({ providerID: input.providerID }))
 
         const result =
diff --git a/packages/opencode/src/provider/auth.ts b/packages/opencode/src/provider/auth.ts
index bc53d874c4..d513085392 100644
--- a/packages/opencode/src/provider/auth.ts
+++ b/packages/opencode/src/provider/auth.ts
@@ -5,6 +5,9 @@ import { fn } from "@/util/fn"
 import * as S from "./auth-service"
 import { ProviderID } from "./schema"
 
+// Separate runtime: ProviderAuthService can't join the shared runtime because
+// runtime.ts → auth-service.ts → provider/auth.ts creates a circular import.
+// AuthService is stateless file I/O so the duplicate instance is harmless.
 const rt = ManagedRuntime.make(S.ProviderAuthService.defaultLayer)
 
 function runPromise<A>(f: (service: S.ProviderAuthService.Service) => Effect.Effect<A, S.ProviderAuthError>) {
diff --git a/packages/opencode/src/util/scoped-state.ts b/packages/opencode/src/util/scoped-state.ts
new file mode 100644
index 0000000000..b709ce6463
--- /dev/null
+++ b/packages/opencode/src/util/scoped-state.ts
@@ -0,0 +1,39 @@
+import { Effect, ScopedCache, Scope } from "effect"
+
+const TypeId = Symbol.for("@opencode/ScopedState")
+
+export interface ScopedState<A, E = never, R = never> {
+  readonly [TypeId]: typeof TypeId
+  readonly root: () => string
+  readonly cache: ScopedCache.ScopedCache<string, A, E, R>
+}
+
+export const make = <A, E = never, R = never>(input: {
+  root: () => string
+  lookup: (key: string) => Effect.Effect<A, E, R>
+  release?: (value: A, key: string) => Effect.Effect<void>
+}): Effect.Effect<ScopedState<A, E, R>, never, Scope.Scope | R> =>
+  ScopedCache.make<string, A, E, R>({
+    capacity: Number.POSITIVE_INFINITY,
+    lookup: (key) =>
+      Effect.acquireRelease(input.lookup(key), (value) => (input.release ? input.release(value, key) : Effect.void)),
+  }).pipe(
+    Effect.map((cache) => ({
+      [TypeId]: TypeId,
+      root: input.root,
+      cache,
+    })),
+  )
+
+export const get = <A, E, R>(self: ScopedState<A, E, R>) => ScopedCache.get(self.cache, self.root())
+
+export const getAt = <A, E, R>(self: ScopedState<A, E, R>, key: string) => ScopedCache.get(self.cache, key)
+
+export const invalidate = <A, E, R>(self: ScopedState<A, E, R>) => ScopedCache.invalidate(self.cache, self.root())
+
+export const invalidateAt = <A, E, R>(self: ScopedState<A, E, R>, key: string) =>
+  ScopedCache.invalidate(self.cache, key)
+
+export const has = <A, E, R>(self: ScopedState<A, E, R>) => ScopedCache.has(self.cache, self.root())
+
+export const hasAt = <A, E, R>(self: ScopedState<A, E, R>, key: string) => ScopedCache.has(self.cache, key)
diff --git a/packages/opencode/test/util/scoped-state.test.ts b/packages/opencode/test/util/scoped-state.test.ts
new file mode 100644
index 0000000000..b54c4c89f9
--- /dev/null
+++ b/packages/opencode/test/util/scoped-state.test.ts
@@ -0,0 +1,164 @@
+import { expect, test } from "bun:test"
+import { Effect, Fiber } from "effect"
+
+import * as ScopedState from "../../src/util/scoped-state"
+
+test("ScopedState caches values for the current root", async () => {
+  let key = "a"
+  let n = 0
+
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const state = yield* ScopedState.make({
+          root: () => key,
+          lookup: () => Effect.sync(() => ({ n: ++n })),
+        })
+
+        const a = yield* ScopedState.get(state)
+        const b = yield* ScopedState.get(state)
+
+        expect(a).toBe(b)
+        expect(n).toBe(1)
+      }),
+    ),
+  )
+})
+
+test("ScopedState isolates values by root", async () => {
+  let key = "a"
+  let n = 0
+
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const state = yield* ScopedState.make({
+          root: () => key,
+          lookup: (root) => Effect.sync(() => ({ root, n: ++n })),
+        })
+
+        const a = yield* ScopedState.get(state)
+        key = "b"
+        const b = yield* ScopedState.get(state)
+        key = "a"
+        const a2 = yield* ScopedState.get(state)
+
+        expect(a).toBe(a2)
+        expect(a).not.toBe(b)
+        expect(n).toBe(2)
+      }),
+    ),
+  )
+})
+
+test("ScopedState.invalidate refreshes the current root", async () => {
+  let n = 0
+
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const state = yield* ScopedState.make({
+          root: () => "a",
+          lookup: () => Effect.sync(() => ({ n: ++n })),
+        })
+
+        const a = yield* ScopedState.get(state)
+        yield* ScopedState.invalidate(state)
+        const b = yield* ScopedState.get(state)
+
+        expect(a).not.toBe(b)
+        expect(n).toBe(2)
+      }),
+    ),
+  )
+})
+
+test("ScopedState.invalidateAt only refreshes the targeted root", async () => {
+  let key = "a"
+  let n = 0
+  const seen: string[] = []
+
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const state = yield* ScopedState.make({
+          root: () => key,
+          lookup: (root) => Effect.sync(() => ({ root, n: ++n })),
+          release: (value, root) =>
+            Effect.sync(() => {
+              seen.push(`${root}:${value.n}`)
+            }),
+        })
+
+        const a = yield* ScopedState.get(state)
+        key = "b"
+        const b = yield* ScopedState.get(state)
+        yield* ScopedState.invalidateAt(state, "a")
+        key = "a"
+        const a2 = yield* ScopedState.get(state)
+        key = "b"
+        const b2 = yield* ScopedState.get(state)
+
+        expect(a).not.toBe(a2)
+        expect(b).toBe(b2)
+        expect(seen).toEqual(["a:1"])
+      }),
+    ),
+  )
+})
+
+test("ScopedState dedupes concurrent lookups for the same root", async () => {
+  const gate = Promise.withResolvers<void>()
+  let n = 0
+
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const state = yield* ScopedState.make({
+          root: () => "a",
+          lookup: () =>
+            Effect.promise(async () => {
+              n += 1
+              await gate.promise
+              return { n }
+            }),
+        })
+
+        const fiber = yield* Effect.all([ScopedState.get(state), ScopedState.get(state)], { concurrency: 2 }).pipe(
+          Effect.forkChild({ startImmediately: true }),
+        )
+
+        yield* Effect.promise(() => Promise.resolve())
+        expect(n).toBe(1)
+
+        gate.resolve()
+        const [a, b] = yield* Fiber.join(fiber)
+        expect(a).toBe(b)
+      }),
+    ),
+  )
+})
+
+test("ScopedState runs release when the surrounding scope closes", async () => {
+  const seen: string[] = []
+
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const state = yield* ScopedState.make({
+          root: () => "a",
+          lookup: (root) => Effect.sync(() => ({ root })),
+          release: (value, root) =>
+            Effect.sync(() => {
+              seen.push(`${root}:${value.root}`)
+            }),
+        })
+
+        yield* ScopedState.get(state)
+        yield* ScopedState.getAt(state, "b")
+      }),
+    ),
+  )
+
+  expect(seen.sort()).toEqual(["a:a", "b:b"])
+})