diff --git a/packages/opencode/test/provider/provider.test.ts b/packages/opencode/test/provider/provider.test.ts
index ea65c90c4fa..2270418beb1 100644
--- a/packages/opencode/test/provider/provider.test.ts
+++ b/packages/opencode/test/provider/provider.test.ts
@@ -582,64 +582,52 @@ it.instance(
   },
 )
 
-test("model options are merged from existing model", 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: {
-            anthropic: {
-              models: {
-                "claude-sonnet-4-20250514": {
-                  options: {
-                    customOption: "custom-value",
-                  },
-                },
+it.instance(
+  "model options are merged from existing model",
+  Effect.gen(function* () {
+    const providers = yield* Provider.Service.use((provider) => provider.list())
+    const model = providers[ProviderID.anthropic].models["claude-sonnet-4-20250514"]
+    expect(model.options.customOption).toBe("custom-value")
+  }),
+  {
+    config: {
+      provider: {
+        anthropic: {
+          options: {
+            apiKey: "test-api-key",
+          },
+          models: {
+            "claude-sonnet-4-20250514": {
+              options: {
+                customOption: "custom-value",
               },
             },
           },
-        }),
-      )
-    },
-  })
-  await WithInstance.provide({
-    directory: tmp.path,
-    fn: async () => {
-      set("ANTHROPIC_API_KEY", "test-api-key")
-      const providers = await list()
-      const model = providers[ProviderID.anthropic].models["claude-sonnet-4-20250514"]
-      expect(model.options.customOption).toBe("custom-value")
+        },
+      },
     },
-  })
-})
+  },
+)
 
-test("provider removed when all models filtered out", 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: {
-            anthropic: {
-              whitelist: ["nonexistent-model"],
-            },
+it.instance(
+  "provider removed when all models filtered out",
+  Effect.gen(function* () {
+    const providers = yield* Provider.Service.use((provider) => provider.list())
+    expect(providers[ProviderID.anthropic]).toBeUndefined()
+  }),
+  {
+    config: {
+      provider: {
+        anthropic: {
+          options: {
+            apiKey: "test-api-key",
           },
-        }),
-      )
-    },
-  })
-  await WithInstance.provide({
-    directory: tmp.path,
-    fn: async () => {
-      set("ANTHROPIC_API_KEY", "test-api-key")
-      const providers = await list()
-      expect(providers[ProviderID.anthropic]).toBeUndefined()
+          whitelist: ["nonexistent-model"],
+        },
+      },
     },
-  })
-})
+  },
+)
 
 test("closest finds model by partial match", async () => {
   await using tmp = await tmpdir({