fix(tui): stabilize compaction completion (#36435)

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

@@ -1064,6 +1064,9 @@ test("tracks session status from active sessions and execution events", async ()
       const message = data.session.message.get("session-manual", "message-compaction")
       return message?.type === "compaction" && message.status === "running" && message.summary === "Streamed summary"
     })
+    const compactionRow = manualRows.find(
+      (row) => row.type === "message" && row.messageID === "message-compaction",
+    )
     emitEvent(events, {
       id: "evt_manual_compaction_ended",
       created: 3,
@@ -1078,6 +1081,9 @@ test("tracks session status from active sessions and execution events", async ()
     expect(manualRows.filter((row) => row.type === "message")).toEqual([
       { type: "message", messageID: "message-compaction" },
     ])
+    expect(manualRows.find((row) => row.type === "message" && row.messageID === "message-compaction")).toBe(
+      compactionRow,
+    )
 
     emitEvent(events, {
       id: "evt_compaction_started",
@@ -1102,6 +1108,9 @@ test("tracks session status from active sessions and execution events", async ()
       const message = data.session.message.get("session-live", "msg_compaction_started")
       return message?.type === "compaction" && message.status === "running" && message.summary === "Live summary"
     })
+    const autoCompactionRow = rows.find(
+      (row) => row.type === "message" && row.messageID === "msg_compaction_started",
+    )
 
     emitEvent(events, {
       id: "evt_compaction_ended",
@@ -1119,6 +1128,10 @@ test("tracks session status from active sessions and execution events", async ()
       status: "completed",
       summary: "Live summary",
     })
+    expect(rows.find((row) => row.type === "message" && row.messageID === "msg_compaction_started")).toBe(
+      autoCompactionRow,
+    )
+    expect(rows.some((row) => row.type === "message" && row.messageID === "msg_compaction_ended")).toBeFalse()
   } finally {
     app.renderer.destroy()
   }

packages/tui/test/util/session.test.ts

@@ -2,6 +2,16 @@ import { describe, expect, test } from "bun:test"
 import type { SessionMessageInfo } from "@opencode-ai/sdk/v2"
 import { isDefaultTitle, lastAssistantWithUsage } from "../../src/util/session"
 
+const assistant = (id: string, input: number): SessionMessageInfo => ({
+  id,
+  type: "assistant",
+  agent: "build",
+  model: { id: "model", providerID: "provider" },
+  content: [],
+  tokens: { input, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+  time: { created: 0 },
+})
+
 describe("util.session", () => {
   test("recognizes generated parent and child titles", () => {
     expect(isDefaultTitle("New session - 2026-06-06T12:34:56.789Z")).toBeTrue()
@@ -10,15 +20,6 @@ describe("util.session", () => {
   })
 
   test("tracks usage across undo and redo boundaries", () => {
-    const assistant = (id: string, input: number): SessionMessageInfo => ({
-      id,
-      type: "assistant",
-      agent: "build",
-      model: { id: "model", providerID: "provider" },
-      content: [],
-      tokens: { input, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
-      time: { created: 0 },
-    })
     const messages = [assistant("msg_z", 10), assistant("msg_a", 30)]
 
     expect(lastAssistantWithUsage(messages)?.tokens.input).toBe(30)
@@ -26,4 +27,22 @@ describe("util.session", () => {
     expect(lastAssistantWithUsage(messages, "msg_missing")).toBeUndefined()
     expect(lastAssistantWithUsage(messages)?.tokens.input).toBe(30)
   })
+
+  test("resets usage at completed compaction until the next assistant reports it", () => {
+    const compaction: SessionMessageInfo = {
+      id: "msg_compaction",
+      type: "compaction",
+      status: "completed",
+      reason: "manual",
+      summary: "Current state",
+      recent: "",
+      time: { created: 0 },
+    }
+    const messages = [assistant("msg_before", 30), compaction]
+
+    expect(lastAssistantWithUsage(messages)).toBeUndefined()
+
+    messages.push(assistant("msg_after", 5))
+    expect(lastAssistantWithUsage(messages)?.tokens.input).toBe(5)
+  })
 })