fix(tui): hide initial instruction sync (#36891)

Co-authored-by: Kit Langton <kit.langton@gmail.com>

packages/core/src/session/instruction-state.ts

@@ -30,6 +30,8 @@ export const prepare = Effect.fn("InstructionState.prepare")(function* (
       SessionEvent.InstructionsUpdated,
       { sessionID, delta: admission.delta },
       {
+        // Initial sync establishes the baseline; unlike later deltas it is not chronological history.
+        ...(!stored ? { metadata: { instructions: { initial: true } } } : {}),
         commit: () => insertBlobs(db, admission.blobs),
       },
     )

packages/core/test/session-runner.test.ts

@@ -943,6 +943,30 @@ describe("SessionRunnerLLM", () => {
     }),
   )
 
+  it.effect("marks the initial instruction sync as baseline metadata", () =>
+    Effect.gen(function* () {
+      const session = yield* setup
+      const events = yield* EventV2.Service
+      const instructionEvents: EventV2.Payload[] = []
+      const unsubscribe = yield* events.listen((event) =>
+        Effect.sync(() => {
+          if (event.type === "session.instructions.updated") instructionEvents.push(event)
+        }),
+      )
+      yield* admit(session, "First")
+
+      yield* session.resume(sessionID)
+      systemBaseline = "Changed context"
+      yield* admit(session, "Second")
+      yield* session.resume(sessionID)
+      yield* unsubscribe
+
+      expect(instructionEvents).toHaveLength(2)
+      expect(instructionEvents[0]?.metadata).toEqual({ instructions: { initial: true } })
+      expect(instructionEvents[1]?.metadata).toBeUndefined()
+    }),
+  )
+
   it.effect("retries the first request after system context becomes available", () =>
     Effect.gen(function* () {
       const session = yield* setup

packages/tui/src/context/data.tsx

@@ -404,6 +404,14 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
           })
           break
         case "session.instructions.updated":
+          const instructions = event.metadata?.instructions
+          if (
+            typeof instructions === "object" &&
+            instructions !== null &&
+            "initial" in instructions &&
+            instructions.initial === true
+          )
+            break
           message.update(event.data.sessionID, (draft, index) => {
             message.append(draft, index, {
               id: messageIDFromEvent(event.id),

packages/tui/test/cli/tui/data.test.tsx

@@ -2385,7 +2385,7 @@ test("renders admitted prompts immediately and tracks them until promoted", asyn
   }
 })
 
-test("projects live instruction updates with their message ID", async () => {
+test("skips initial instruction state and projects later updates with their message ID", async () => {
   const events = createEventStream()
   const calls = createFetch(undefined, events)
   let sync!: ReturnType<typeof useData>
@@ -2419,18 +2419,30 @@ test("projects live instruction updates with their message ID", async () => {
       created: 0,
       type: "session.instructions.updated",
       durable: durable("session-1", 0, 2),
+      metadata: { instructions: { initial: true } },
       data: {
         sessionID: "session-1",
         delta: { "core/date": "0".repeat(64) },
       },
     })
+    emitEvent(events, {
+      id: "evt_instructions_2",
+      created: 1,
+      type: "session.instructions.updated",
+      durable: durable("session-1", 1, 2),
+      data: {
+        sessionID: "session-1",
+        delta: { "core/date": "1".repeat(64) },
+      },
+    })
 
-    await wait(() => sync.session.message.list("session-1")?.length === 1)
+    await wait(() => sync.session.message.list("session-1")?.some((message) => message.time.created === 1))
+    expect(sync.session.message.list("session-1")).toHaveLength(1)
     expect(sync.session.message.list("session-1")?.[0]).toMatchObject({
-      id: SessionMessage.ID.fromEvent(EventV2.ID.make("evt_instructions_1")),
+      id: SessionMessage.ID.fromEvent(EventV2.ID.make("evt_instructions_2")),
       type: "system",
       text: "Instructions updated: core/date",
-      time: { created: 0 },
+      time: { created: 1 },
     })
   } finally {
     app.renderer.destroy()