diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
index cdb9d2057245..ea65c90c4fa1 100644
--- a/packages/opencode/test/provider/provider.test.ts
+++ b/packages/opencode/test/provider/provider.test.ts
@@ -15,6 +15,7 @@ import { Env } from "../../src/env"
 import { Effect } from "effect"
 import { AppRuntime } from "../../src/effect/app-runtime"
 import { makeRuntime } from "../../src/effect/run-service"
+import { testEffect } from "../lib/effect"
 
 const env = makeRuntime(Env.Service, Env.defaultLayer)
 const set = (k: string, v: string) => env.runSync((svc) => svc.set(k, v))
@@ -70,6 +71,8 @@ function paid(providers: Awaited<ReturnType<typeof list>>) {
   return Object.values(item.models).filter((model) => model.cost.input > 0).length
 }
 
+const it = testEffect(Provider.defaultLayer)
+
 test("provider loaded from env variable", async () => {
   await using tmp = await tmpdir({
     init: async (dir) => {
@@ -515,85 +518,69 @@ test("defaultModel respects config model setting", async () => {
   })
 })
 
-test("provider with baseURL from config", async () => {
-  await using tmp = await tmpdir({
-    init: async (dir) => {
-      await Bun.write(
-        path.join(dir, "opencode.json"),
-        JSON.stringify({
-          $schema: "https://opencode.ai/config.json",
-          provider: {
-            "custom-openai": {
-              name: "Custom OpenAI",
-              npm: "@ai-sdk/openai-compatible",
-              env: [],
-              models: {
-                "gpt-4": {
-                  name: "GPT-4",
-                  tool_call: true,
-                  limit: { context: 128000, output: 4096 },
-                },
-              },
-              options: {
-                apiKey: "test-key",
-                baseURL: "https://custom.openai.com/v1",
-              },
+it.instance(
+  "provider with baseURL from config",
+  Effect.gen(function* () {
+    const providers = yield* Provider.Service.use((provider) => provider.list())
+    expect(providers[ProviderID.make("custom-openai")]).toBeDefined()
+    expect(providers[ProviderID.make("custom-openai")].options.baseURL).toBe("https://custom.openai.com/v1")
+  }),
+  {
+    config: {
+      provider: {
+        "custom-openai": {
+          name: "Custom OpenAI",
+          npm: "@ai-sdk/openai-compatible",
+          env: [],
+          models: {
+            "gpt-4": {
+              name: "GPT-4",
+              tool_call: true,
+              limit: { context: 128000, output: 4096 },
             },
           },
-        }),
-      )
-    },
-  })
-  await WithInstance.provide({
-    directory: tmp.path,
-    fn: async () => {
-      const providers = await list()
-      expect(providers[ProviderID.make("custom-openai")]).toBeDefined()
-      expect(providers[ProviderID.make("custom-openai")].options.baseURL).toBe("https://custom.openai.com/v1")
+          options: {
+            apiKey: "test-key",
+            baseURL: "https://custom.openai.com/v1",
+          },
+        },
+      },
     },
-  })
-})
-
-test("model cost defaults to zero when not specified", async () => {
-  await using tmp = await tmpdir({
-    init: async (dir) => {
-      await Bun.write(
-        path.join(dir, "opencode.json"),
-        JSON.stringify({
-          $schema: "https://opencode.ai/config.json",
-          provider: {
-            "test-provider": {
-              name: "Test Provider",
-              npm: "@ai-sdk/openai-compatible",
-              env: [],
-              models: {
-                "test-model": {
-                  name: "Test Model",
-                  tool_call: true,
-                  limit: { context: 128000, output: 4096 },
-                },
-              },
-              options: {
-                apiKey: "test-key",
-              },
+  },
+)
+
+it.instance(
+  "model cost defaults to zero when not specified",
+  Effect.gen(function* () {
+    const providers = yield* Provider.Service.use((provider) => provider.list())
+    const model = providers[ProviderID.make("test-provider")].models["test-model"]
+    expect(model.cost.input).toBe(0)
+    expect(model.cost.output).toBe(0)
+    expect(model.cost.cache.read).toBe(0)
+    expect(model.cost.cache.write).toBe(0)
+  }),
+  {
+    config: {
+      provider: {
+        "test-provider": {
+          name: "Test Provider",
+          npm: "@ai-sdk/openai-compatible",
+          env: [],
+          models: {
+            "test-model": {
+              name: "Test Model",
+              tool_call: true,
+              limit: { context: 128000, output: 4096 },
             },
           },
-        }),
-      )
-    },
-  })
-  await WithInstance.provide({
-    directory: tmp.path,
-    fn: async () => {
-      const providers = await list()
-      const model = providers[ProviderID.make("test-provider")].models["test-model"]
-      expect(model.cost.input).toBe(0)
-      expect(model.cost.output).toBe(0)
-      expect(model.cost.cache.read).toBe(0)
-      expect(model.cost.cache.write).toBe(0)
+          options: {
+            apiKey: "test-key",
+          },
+        },
+      },
     },
-  })
-})
+  },
+)
 
 test("model options are merged from existing model", async () => {
   await using tmp = await tmpdir({