diff --git a/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts b/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
index daacfec63c..80bff42bc1 100644
--- a/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
+++ b/packages/opencode/src/server/routes/instance/httpapi/handlers/session.ts
@@ -14,7 +14,6 @@ import { SessionStatus } from "@/session/status"
 import { SessionSummary } from "@/session/summary"
 import { Todo } from "@/session/todo"
 import { MessageID, PartID, SessionID } from "@/session/schema"
-import { NotFoundError } from "@/storage/storage"
 import { NamedError } from "@opencode-ai/core/util/error"
 import { Cause, Effect, Option, Schema, Scope } from "effect"
 import * as Stream from "effect/Stream"
@@ -105,11 +104,13 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
         return yield* session.messages({ sessionID: ctx.params.sessionID })
       }
 
-      const page = MessageV2.page({
-        sessionID: ctx.params.sessionID,
-        limit: ctx.query.limit,
-        before: ctx.query.before,
-      })
+      const page = yield* SessionError.mapStorageNotFound(
+        MessageV2.pageEffect({
+          sessionID: ctx.params.sessionID,
+          limit: ctx.query.limit,
+          before: ctx.query.before,
+        }),
+      )
       if (!page.cursor) return page.items
 
       const request = yield* HttpServerRequest.HttpServerRequest
@@ -131,10 +132,7 @@ export const sessionHandlers = HttpApiBuilder.group(InstanceHttpApi, "session",
       params: { sessionID: SessionID; messageID: MessageID }
     }) {
       return yield* SessionError.mapStorageNotFound(
-        Effect.try({
-          try: () => MessageV2.get({ sessionID: ctx.params.sessionID, messageID: ctx.params.messageID }),
-          catch: (error) => error,
-        }).pipe(Effect.catch((error) => (NotFoundError.isInstance(error) ? Effect.fail(error) : Effect.die(error)))),
+        MessageV2.getEffect({ sessionID: ctx.params.sessionID, messageID: ctx.params.messageID }),
       )
     })
 
diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
index e6ee40e953..10754298b2 100644
--- a/packages/opencode/src/session/message-v2.ts
+++ b/packages/opencode/src/session/message-v2.ts
@@ -956,6 +956,17 @@ export function page(input: { sessionID: SessionID; limit: number; before?: stri
   }
 }
 
+export const pageEffect = Effect.fn("MessageV2.pageEffect")(function* (input: {
+  sessionID: SessionID
+  limit: number
+  before?: string
+}) {
+  return yield* Effect.try({
+    try: () => page(input),
+    catch: (error) => error,
+  }).pipe(Effect.catch((error) => (NotFoundError.isInstance(error) ? Effect.fail(error) : Effect.die(error))))
+})
+
 export function* stream(sessionID: SessionID) {
   const size = 50
   let before: string | undefined
@@ -1000,6 +1011,16 @@ export function get(input: { sessionID: SessionID; messageID: MessageID }): With
   }
 }
 
+export const getEffect = Effect.fn("MessageV2.getEffect")(function* (input: {
+  sessionID: SessionID
+  messageID: MessageID
+}) {
+  return yield* Effect.try({
+    try: () => get(input),
+    catch: (error) => error,
+  }).pipe(Effect.catch((error) => (NotFoundError.isInstance(error) ? Effect.fail(error) : Effect.die(error))))
+})
+
 export function filterCompacted(msgs: Iterable<WithParts>) {
   const result = [] as WithParts[]
   const completed = new Set<string>()
diff --git a/packages/opencode/test/session/messages-pagination.test.ts b/packages/opencode/test/session/messages-pagination.test.ts
index 5585aa0b01..8332bb9b3d 100644
--- a/packages/opencode/test/session/messages-pagination.test.ts
+++ b/packages/opencode/test/session/messages-pagination.test.ts
@@ -205,6 +205,15 @@ describe("MessageV2.page", () => {
     }),
   )
 
+  it.instance("fails pageEffect with NotFoundError for non-existent session", () =>
+    Effect.gen(function* () {
+      const fake = "non-existent-session" as SessionID
+      const error = yield* Effect.flip(MessageV2.pageEffect({ sessionID: fake, limit: 10 }))
+      expect(error).toBeInstanceOf(NotFoundError)
+      expect(error.message).toBe(`Session not found: ${fake}`)
+    }),
+  )
+
   it.instance("handles exact limit boundary", () =>
     withSession(({ sessionID }) =>
       Effect.gen(function* () {
@@ -492,6 +501,17 @@ describe("MessageV2.get", () => {
     ),
   )
 
+  it.instance("fails getEffect with NotFoundError for non-existent message", () =>
+    withSession(({ sessionID }) =>
+      Effect.gen(function* () {
+        const messageID = MessageID.ascending()
+        const error = yield* Effect.flip(MessageV2.getEffect({ sessionID, messageID }))
+        expect(error).toBeInstanceOf(NotFoundError)
+        expect(error.message).toBe(`Message not found: ${messageID}`)
+      }),
+    ),
+  )
+
   it.instance("scopes by session id", () =>
     Effect.gen(function* () {
       const session = yield* SessionNs.Service