diff --git a/packages/opencode/src/server/instance/session.ts b/packages/opencode/src/server/instance/session.ts
index 8db48b73a..7cfb08967 100644
--- a/packages/opencode/src/server/instance/session.ts
+++ b/packages/opencode/src/server/instance/session.ts
@@ -662,10 +662,15 @@ export const SessionRoutes = lazy(() =>
       async (c) => {
         const query = c.req.valid("query")
         const params = c.req.valid("param")
-        const result = await SessionSummary.diff({
-          sessionID: params.sessionID,
-          messageID: query.messageID,
-        })
+        const result = await AppRuntime.runPromise(
+          Effect.gen(function* () {
+            const summary = yield* SessionSummary.Service
+            return yield* summary.diff({
+              sessionID: params.sessionID,
+              messageID: query.messageID,
+            })
+          }),
+        )
         return c.json(result)
       },
     )
@@ -926,9 +931,14 @@ export const SessionRoutes = lazy(() =>
       ),
       async (c) => {
         const params = c.req.valid("param")
-        const result = await SessionSummary.artifacts({
-          sessionID: params.sessionID,
-        })
+        const result = await AppRuntime.runPromise(
+          Effect.gen(function* () {
+            const summary = yield* SessionSummary.Service
+            return yield* summary.artifacts({
+              sessionID: params.sessionID,
+            })
+          }),
+        )
         return c.json(result)
       },
     )
diff --git a/packages/opencode/test/server/session-runtime-routes.test.ts b/packages/opencode/test/server/session-runtime-routes.test.ts
index 8b5619e71..d7b425aa5 100644
--- a/packages/opencode/test/server/session-runtime-routes.test.ts
+++ b/packages/opencode/test/server/session-runtime-routes.test.ts
@@ -30,7 +30,7 @@ afterEach(async () => {
 })
 
 describe("session runtime routes", () => {
-  test("share, unshare, artifacts, command, and shell routes are wired through the instance router", async () => {
+  test("share, unshare, diff, artifacts, command, and shell routes are wired through the instance router", async () => {
     await using tmp = await tmpdir({ git: true })
     await Instance.provide({
       directory: tmp.path,
@@ -70,6 +70,10 @@ describe("session runtime routes", () => {
         expect(artifactsRes.status).toBe(200)
         expect(Array.isArray(await artifactsRes.json())).toBe(true)
 
+        const diffRes = await app.request(`/session/${session.id}/diff`)
+        expect(diffRes.status).toBe(200)
+        expect(await diffRes.json()).toHaveProperty("kind")
+
         const commandRes = await app.request(`/session/${session.id}/command`, {
           method: "POST",
           headers: { "Content-Type": "application/json" },