diff --git a/scripts/src/cli.ts b/scripts/src/cli.ts
index 713d61f..67fef58 100644
--- a/scripts/src/cli.ts
+++ b/scripts/src/cli.ts
@@ -633,7 +633,7 @@ export function summarizeQueueAttemptListResult(result: JsonValue, taskId: strin
 function summarizeRunEvent(event: JsonRecord, summaryChars: number): JsonRecord {
   const payload = jsonRecordValue(event.payload) ?? {};
   const type = stringValue(event.type) ?? "unknown";
-  const messageEvent = type === "user_message" || type === "assistant_message";
+  const messageEvent = type === "user_message" || type === "assistant_progress" || type === "assistant_message";
   const command = messageEvent ? null : boundedSummaryString(stringValue(payload.command), Math.min(summaryChars, 240));
   const text = messageEvent ? boundedSummaryString(stringValue(payload.text), summaryChars) : null;
   const outputSummary = boundedSummaryString(stringValue(payload.outputSummary) ?? nestedSummaryText(payload), summaryChars);
@@ -668,7 +668,7 @@ function summarizeRunEvent(event: JsonRecord, summaryChars: number): JsonRecord
 
 function isDefaultVisibleSessionEvent(item: JsonRecord): boolean {
   const type = stringValue(item.type);
-  return type === "user_message" || type === "assistant_message" || type === "tool_call" || type === "error";
+  return type === "user_message" || type === "assistant_progress" || type === "assistant_message" || type === "tool_call" || type === "error";
 }
 
 function summarizeSuppressedSessionEvents(all: JsonRecord[], visible: JsonRecord[]): JsonRecord {
diff --git a/src/backend/codex-stdio.ts b/src/backend/codex-stdio.ts
index 86b0d24..d364d1d 100644
--- a/src/backend/codex-stdio.ts
+++ b/src/backend/codex-stdio.ts
@@ -1424,7 +1424,7 @@ function flushAssistantDeltaProgress(state: AssistantDeltaProgressState): Backen
 function assistantDeltaProgressEvent(item: AssistantDeltaProgressItem, flush: boolean): BackendEvent {
   const summary = boundedTextSummary(item.text.trim(), { limitChars: assistantDeltaProgressLimitChars });
   return {
-    type: "assistant_message",
+    type: "assistant_progress",
     payload: {
       text: summary.text,
       itemId: item.itemId,
diff --git a/src/common/events.ts b/src/common/events.ts
index c66c870..ad6716f 100644
--- a/src/common/events.ts
+++ b/src/common/events.ts
@@ -4,8 +4,8 @@ import { boundedTextSummary, commandOutputPayload } from "./output.js";
 import { agentRunBusinessTraceId } from "./otel-trace.js";
 import { redactJson, redactText } from "./redaction.js";
 
-export const eventTypes = ["backend_status", "user_message", "assistant_message", "tool_call", "command_output", "diff", "error", "terminal_status"] as const satisfies readonly EventType[];
-export const externallyAppendableEventTypes = ["backend_status", "assistant_message", "tool_call", "command_output", "diff", "error", "terminal_status"] as const satisfies readonly EventType[];
+export const eventTypes = ["backend_status", "user_message", "assistant_progress", "assistant_message", "tool_call", "command_output", "diff", "error", "terminal_status"] as const satisfies readonly EventType[];
+export const externallyAppendableEventTypes = ["backend_status", "assistant_progress", "assistant_message", "tool_call", "command_output", "diff", "error", "terminal_status"] as const satisfies readonly EventType[];
 export const terminalStatuses = ["completed", "failed", "blocked", "cancelled"] as const satisfies readonly TerminalStatus[];
 
 const eventTypeSet = new Set<string>(eventTypes);
@@ -41,6 +41,7 @@ export function normalizeRunEventPayload(type: EventType, payload: JsonRecord):
   if (type === "terminal_status") return normalizeTerminalStatusPayload(payload);
   if (type === "command_output") return normalizeCommandOutputPayload(payload);
   if (type === "user_message") return normalizeUserMessagePayload(payload);
+  if (type === "assistant_progress") return normalizeAssistantProgressPayload(payload);
   if (type === "assistant_message") return normalizeTextPayload(payload);
   if (type === "tool_call") return normalizeToolCallPayload(payload);
   return payload;
@@ -140,6 +141,22 @@ function normalizeTextPayload(payload: JsonRecord): JsonRecord {
   return { ...rest, text: summary.text, summary, textBytes: summary.textBytes, textTruncated: summary.textTruncated, outputBytes: summary.outputBytes, outputTruncated: summary.outputTruncated };
 }
 
+function normalizeAssistantProgressPayload(payload: JsonRecord): JsonRecord {
+  const source = nonEmptyText(payload.source);
+  const text = typeof payload.text === "string" ? payload.text : typeof payload.delta === "string" ? payload.delta : typeof payload.content === "string" ? payload.content : "";
+  if (source !== "agent-message-delta-progress" || payload.progress !== true || payload.replyAuthority !== false || payload.final !== false || payload.durableText === true || text.trim().length === 0) {
+    throw new AgentRunError("schema-invalid", "assistant_progress requires non-empty delta progress with replyAuthority=false, final=false, and non-durable text", { httpStatus: 400 });
+  }
+  return normalizeTextPayload({
+    ...payload,
+    source,
+    progress: true,
+    replyAuthority: false,
+    final: false,
+    valuesPrinted: false,
+  });
+}
+
 function normalizeDurableAssistantText(payload: JsonRecord, body: string): JsonRecord {
   const source = typeof payload.source === "string" ? payload.source : "";
   if (source !== "completed-agent-message" && source !== "agent-message-delta-fallback") {
diff --git a/src/common/types.ts b/src/common/types.ts
index 038d275..2425b9b 100644
--- a/src/common/types.ts
+++ b/src/common/types.ts
@@ -336,7 +336,7 @@ export interface CancelRequestRecord extends JsonRecord {
   updatedAt: string;
 }
 
-export type EventType = "backend_status" | "user_message" | "assistant_message" | "tool_call" | "command_output" | "diff" | "error" | "terminal_status";
+export type EventType = "backend_status" | "user_message" | "assistant_progress" | "assistant_message" | "tool_call" | "command_output" | "diff" | "error" | "terminal_status";
 
 export interface RunEvent extends JsonRecord {
   id: string;
diff --git a/src/mgr/diagnosis.ts b/src/mgr/diagnosis.ts
index acabea4..27204d5 100644
--- a/src/mgr/diagnosis.ts
+++ b/src/mgr/diagnosis.ts
@@ -295,7 +295,7 @@ function isRunnerJobActivity(job: RunnerJobRecord, event: RunEvent): boolean {
   if (payload?.phase === "runner-job-created") return false;
   if (payload?.runnerId === job.runnerId || payload?.attemptId === job.attemptId) return true;
   if (payload?.commandId === job.commandId) {
-    if (event.type === "tool_call" || event.type === "assistant_message" || event.type === "command_output" || event.type === "error") return true;
+    if (event.type === "tool_call" || event.type === "assistant_progress" || event.type === "assistant_message" || event.type === "command_output" || event.type === "error") return true;
     if (event.type === "backend_status" && typeof payload.phase === "string" && payload.phase !== "command-created") return true;
   }
   return false;
diff --git a/src/mgr/result.ts b/src/mgr/result.ts
index dc20229..d62e7a1 100644
--- a/src/mgr/result.ts
+++ b/src/mgr/result.ts
@@ -213,7 +213,7 @@ function livenessPhase(input: { active: boolean; command: CommandRecord | null;
     if (status === "completed") return "idle-after-tool";
   }
   if (input.lastVisibleActivity?.type === "command_output") return "waiting-tool-output";
-  if (input.lastVisibleActivity?.type === "assistant_message") return "waiting-model-output";
+  if (input.lastVisibleActivity?.type === "assistant_progress" || input.lastVisibleActivity?.type === "assistant_message") return "waiting-model-output";
   const remainingMs = numberJsonValue(input.timeoutBudget.remainingMs);
   const timeoutMs = numberJsonValue(input.timeoutBudget.timeoutMs);
   const activityAgeMs = numberJsonValue(input.lastActivity?.ageMs);
@@ -402,15 +402,15 @@ function latestLivenessActivity(events: RunEvent[]): RunEvent | null {
 }
 
 function latestVisibleActivity(events: RunEvent[]): RunEvent | null {
-  return [...events].reverse().find((event) => event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status") ?? null;
+  return [...events].reverse().find((event) => event.type === "assistant_progress" || event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status") ?? null;
 }
 
 function latestBusinessActivity(events: RunEvent[]): RunEvent | null {
-  return [...events].reverse().find((event) => event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff") ?? null;
+  return [...events].reverse().find((event) => event.type === "assistant_progress" || event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff") ?? null;
 }
 
 function isLivenessActivityEvent(event: RunEvent): boolean {
-  if (event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status") return true;
+  if (event.type === "assistant_progress" || event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status") return true;
   if (event.type !== "backend_status") return false;
   const phase = typeof event.payload.phase === "string" ? event.payload.phase : "";
   return ["backend-turn-started", "thread/start:completed", "thread/resume:completed", "turn/start:completed", "backend-turn-finished", "codex-app-server-closed"].includes(phase);
@@ -458,7 +458,8 @@ function activityKind(event: RunEvent): string {
     return "tool";
   }
   if (event.type === "command_output") return "tool-output";
-  if (event.type === "assistant_message") return event.payload.progress === true ? "assistant-progress" : "assistant-output";
+  if (event.type === "assistant_progress") return "assistant-progress";
+  if (event.type === "assistant_message") return "assistant-output";
   if (event.type === "diff") return "diff";
   if (event.type === "error") return "error";
   if (event.type === "terminal_status") return "terminal";
@@ -621,7 +622,7 @@ function targetFollowUpAfterSeq(events: RunEvent[], targetCommandId: string, aft
 }
 
 function isTargetFollowUpEvent(event: RunEvent): boolean {
-  return event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status";
+  return event.type === "assistant_progress" || event.type === "assistant_message" || event.type === "tool_call" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status";
 }
 
 function runIsTerminal(run: RunRecord): boolean {
diff --git a/src/mgr/store.ts b/src/mgr/store.ts
index 5774cd2..915b572 100644
--- a/src/mgr/store.ts
+++ b/src/mgr/store.ts
@@ -1675,5 +1675,5 @@ function workQueueStatus<T extends JsonRecord>(items: T[], component: string, co
 }
 
 export function isSessionOutputEvent(event: RunEvent): boolean {
-  return event.type === "assistant_message" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status";
+  return event.type === "assistant_progress" || event.type === "assistant_message" || event.type === "command_output" || event.type === "diff" || event.type === "error" || event.type === "terminal_status";
 }
diff --git a/src/selftest/cases/15-cli-events-summary.ts b/src/selftest/cases/15-cli-events-summary.ts
index b0edbbe..5f1aa9a 100644
--- a/src/selftest/cases/15-cli-events-summary.ts
+++ b/src/selftest/cases/15-cli-events-summary.ts
@@ -38,11 +38,20 @@ export default function selfTest(_context: SelfTestContext): SelfTestResult {
   assert.equal(userMessageItem?.summary, "replay this user input");
   assert.equal(userMessageItem?.text, "replay this user input");
 
+  const progressSummary = summarizeRunEventPage({ items: [
+    { id: "evt_progress", seq: 15, type: "assistant_progress", payload: { commandId: "cmd_progress", itemId: "msg_progress", text: "live cumulative assistant progress", source: "agent-message-delta-progress", progress: true, replyAuthority: false, final: false } },
+  ] }, { runId: "run_selftest", afterSeq: 14, limit: 1, tail: null, summaryChars: 80 });
+  const progressItem = (progressSummary.items as JsonRecord[])[0];
+  assert.equal(progressItem?.type, "assistant_progress");
+  assert.equal(progressItem?.summary, "live cumulative assistant progress");
+  assert.equal(progressItem?.text, "live cumulative assistant progress");
+
   const hugeRunnerTrace = "runner trace line with test-token-material\n".repeat(2_000);
   const sessionSummary = summarizeSessionEventPage({
     sessionId: "sess_noise",
     runId: "run_noise",
     items: [
+      { id: "evt_progress", seq: 264, type: "assistant_progress", payload: { itemId: "msg_noise", text: "still working", source: "agent-message-delta-progress", progress: true, replyAuthority: false, final: false } },
       { id: "evt_tool", seq: 265, type: "tool_call", payload: { itemId: "tool_noise", method: "commandExecution", status: "completed", command: "printf hidden", outputSummary: "tool completed" } },
       { id: "evt_output", seq: 266, type: "command_output", payload: { itemId: "tool_noise", text: hugeRunnerTrace, outputSummary: "large stdout", outputBytes: 100_000, outputTruncated: true } },
       {
@@ -58,21 +67,21 @@ export default function selfTest(_context: SelfTestContext): SelfTestResult {
         },
       },
     ],
-    count: 3,
+    count: 4,
     cursor: "266",
   }, { kind: "trace", sessionId: "sess_noise", afterSeq: 250, limit: 100, runId: null, tail: null, summaryChars: 80, includeOutput: false });
   const sessionItems = sessionSummary.items as JsonRecord[];
   assert.equal(sessionSummary.action, "session-trace-summary");
-  assert.equal(sessionSummary.sourceCount, 3);
-  assert.equal(sessionSummary.displayedCount, 1);
+  assert.equal(sessionSummary.sourceCount, 4);
+  assert.equal(sessionSummary.displayedCount, 2);
   assert.equal(sessionSummary.nextAfterSeq, 267);
   assert.equal((sessionSummary.suppressedEvents as JsonRecord).count, 2);
   assert.equal(((sessionSummary.suppressedEvents as JsonRecord).byType as JsonRecord).command_output, 1);
   assert.equal(((sessionSummary.suppressedEvents as JsonRecord).byType as JsonRecord).backend_status, 1);
-  assert.deepEqual(sessionItems.map((item) => item.type), ["tool_call"]);
-  assert.equal(((sessionItems[0]?.detailCommands as JsonRecord).item as string).includes("--after-seq 264 --limit 1"), true);
-  assert.equal(((sessionItems[0]?.detailCommands as JsonRecord).item as string).includes("--item-id tool_noise"), true);
-  assert.equal(((sessionItems[0]?.detailCommands as JsonRecord).seq as string).includes("--seq 265"), true);
+  assert.deepEqual(sessionItems.map((item) => item.type), ["assistant_progress", "tool_call"]);
+  assert.equal(((sessionItems[1]?.detailCommands as JsonRecord).item as string).includes("--after-seq 264 --limit 1"), true);
+  assert.equal(((sessionItems[1]?.detailCommands as JsonRecord).item as string).includes("--item-id tool_noise"), true);
+  assert.equal(((sessionItems[1]?.detailCommands as JsonRecord).seq as string).includes("--seq 265"), true);
   assert.ok(Number((sessionSummary.suppressedEvents as JsonRecord).outputBytes) > 0);
   assert.equal(JSON.stringify(sessionSummary).includes("runner trace line"), false);
   assert.equal(String((sessionSummary.drillDownCommands as JsonRecord).full).includes("--full"), true);
diff --git a/src/selftest/cases/30-codex-stdio.ts b/src/selftest/cases/30-codex-stdio.ts
index 20d3c59..6cbcae5 100644
--- a/src/selftest/cases/30-codex-stdio.ts
+++ b/src/selftest/cases/30-codex-stdio.ts
@@ -130,7 +130,7 @@ const selfTest: SelfTestCase = async (context) => {
     const webSearch = await createRunWithCommand(client, context, "hello web search progress", "selftest-web-search-progress", 15_000);
     const webSearchPromise = runOnce({ managerUrl: server.baseUrl, runId: webSearch.runId, codexCommand: context.fakeCodexCommand, codexArgs: context.fakeCodexArgs, codexHome: context.codexHome, env: { CODEX_HOME: context.codexHome, AGENTRUN_FAKE_CODEX_MODE: "web-search-progress" }, oneShot: true }) as Promise<JsonRecord>;
     await waitForEvent(client, webSearch.runId, (event) => event.type === "tool_call" && eventPayload(event).type === "webSearch" && eventPayload(event).method === "item/started", "webSearch tool_call start event");
-    await waitForEvent(client, webSearch.runId, (event) => event.type === "assistant_message" && eventPayload(event).source === "agent-message-delta-progress", "assistant delta progress event");
+    await waitForEvent(client, webSearch.runId, (event) => event.type === "assistant_progress" && eventPayload(event).source === "agent-message-delta-progress", "assistant delta progress event");
     const webSearchResult = await webSearchPromise;
     assert.equal(webSearchResult.terminalStatus, "completed", "web search progress turn should complete");
     const webSearchEnvelope = await client.get(`/api/v1/runs/${webSearch.runId}/commands/${webSearch.commandId}/result`) as JsonRecord;
@@ -138,9 +138,9 @@ const selfTest: SelfTestCase = async (context) => {
     const webSearchEvents = await client.get(`/api/v1/runs/${webSearch.runId}/events?afterSeq=0&limit=100`) as { items?: Array<{ type: string; payload: unknown }> };
     const webSearchItems = webSearchEvents.items ?? [];
     assert.ok(webSearchItems.some((event) => event.type === "tool_call" && eventPayload(event).type === "webSearch" && eventPayload(event).method === "item/completed"), "webSearch completion must remain visible as a tool_call");
-    assert.ok(webSearchItems.some((event) => event.type === "assistant_message" && eventPayload(event).source === "agent-message-delta-progress" && eventPayload(event).progress === true), "assistant delta progress must be visible before final reply");
+    assert.ok(webSearchItems.some((event) => event.type === "assistant_progress" && eventPayload(event).source === "agent-message-delta-progress" && eventPayload(event).progress === true), "assistant delta progress must be visible before final reply");
     const webSearchStartIndex = webSearchItems.findIndex((event) => event.type === "tool_call" && eventPayload(event).type === "webSearch" && eventPayload(event).method === "item/started");
-    const webSearchProgressIndex = webSearchItems.findIndex((event) => event.type === "assistant_message" && eventPayload(event).source === "agent-message-delta-progress");
+    const webSearchProgressIndex = webSearchItems.findIndex((event) => event.type === "assistant_progress" && eventPayload(event).source === "agent-message-delta-progress");
     const webSearchCompletedIndex = webSearchItems.findIndex((event) => event.type === "tool_call" && eventPayload(event).type === "webSearch" && eventPayload(event).method === "item/completed");
     const webSearchFinalIndex = webSearchItems.findIndex((event) => event.type === "assistant_message" && eventPayload(event).source === "completed-agent-message" && eventPayload(event).itemId === "msg_search");
     assert.ok(webSearchStartIndex >= 0 && webSearchStartIndex < webSearchProgressIndex, "webSearch start should be visible before assistant progress");
diff --git a/src/selftest/cases/55-timeout-liveness.ts b/src/selftest/cases/55-timeout-liveness.ts
index 88d3a33..cee6566 100644
--- a/src/selftest/cases/55-timeout-liveness.ts
+++ b/src/selftest/cases/55-timeout-liveness.ts
@@ -24,7 +24,7 @@ const selfTest: SelfTestCase = async (context: SelfTestContext) => {
     assert.ok(Array.isArray(toolLive.recoveryActions));
 
     const assistant = await createActiveRun(client, context, "timeout-liveness-assistant", 120_000);
-    await client.post(`/api/v1/runs/${assistant.runId}/events`, { type: "assistant_message", payload: { commandId: assistant.commandId, itemId: "msg_progress", progress: true, text: "正在生成 apply-patch，先汇总待改文件。" } });
+    await client.post(`/api/v1/runs/${assistant.runId}/events`, { type: "assistant_progress", payload: { commandId: assistant.commandId, itemId: "msg_progress", source: "agent-message-delta-progress", progress: true, replyAuthority: false, final: false, text: "正在生成 apply-patch，先汇总待改文件。" } });
     const assistantLive = (await commandResult(client, assistant)).liveness as JsonRecord;
     assert.equal(assistantLive.phase, "waiting-model-output");
     assert.equal(((assistantLive.lastActivity as JsonRecord).activityKind), "assistant-progress");
diff --git a/src/selftest/cases/80-assistant-final-seal.ts b/src/selftest/cases/80-assistant-final-seal.ts
index 6daff94..2983c40 100644
--- a/src/selftest/cases/80-assistant-final-seal.ts
+++ b/src/selftest/cases/80-assistant-final-seal.ts
@@ -4,6 +4,8 @@ import { ManagerClient } from "../../mgr/client.js";
 import { startManagerServer } from "../../mgr/server.js";
 import { MemoryAgentRunStore } from "../../mgr/store.js";
 import { runOnce } from "../../runner/run-once.js";
+import { CodexStdioEventReducer } from "../../backend/codex-stdio.js";
+import { normalizeRunEventPayload } from "../../common/events.js";
 import { createRunWithCommand, type SelfTestCase, type SelfTestContext } from "../harness.js";
 
 interface EventRecord {
@@ -13,6 +15,7 @@ interface EventRecord {
 }
 
 const selfTest: SelfTestCase = async (context) => {
+  assertCumulativeProgressEventContract();
   const server = await startManagerServer({
     port: 0,
     host: "127.0.0.1",
@@ -43,6 +46,7 @@ const selfTest: SelfTestCase = async (context) => {
         "assistant-final-seal-delta-fallback",
         "assistant-progress-completed-item-fence",
         "assistant-progress-anonymous-generation-fence",
+        "assistant-progress-distinct-event-contract",
         "assistant-final-seal-control-event",
       ],
     };
@@ -51,6 +55,57 @@ const selfTest: SelfTestCase = async (context) => {
   }
 };
 
+function assertCumulativeProgressEventContract(): void {
+  const reducer = new CodexStdioEventReducer();
+  const first = "a".repeat(500);
+  const second = "b".repeat(503);
+  const third = "c".repeat(187);
+  const text = `${first}${second}${third}`;
+  const rawEvents = [
+    ...reducer.reduce(notification("item/agentMessage/delta", { itemId: "msg_fixed_progress", delta: first })).events,
+    ...reducer.reduce(notification("item/agentMessage/delta", { itemId: "msg_fixed_progress", delta: second })).events,
+    ...reducer.reduce(notification("item/agentMessage/delta", { itemId: "msg_fixed_progress", delta: third })).events,
+    ...reducer.reduce(notification("item/completed", { item: { id: "msg_fixed_progress", type: "agentMessage", text } })).events,
+  ];
+  const terminal = reducer.reduce(notification("turn/completed", { turn: { id: "turn_fixed_progress", status: "completed" } }));
+  const events = [...rawEvents, ...terminal.events, ...reducer.finalize(terminal.terminal ?? null)].map((event) => ({
+    ...event,
+    payload: normalizeRunEventPayload(event.type, event.payload),
+  }));
+
+  assert.deepEqual(events.map((event) => event.type), [
+    "assistant_progress",
+    "assistant_progress",
+    "assistant_message",
+    "backend_status",
+    "backend_status",
+    "terminal_status",
+  ]);
+  const progress = events.filter((event) => event.type === "assistant_progress");
+  assert.deepEqual(progress.map((event) => event.payload.textBytes), [500, 1_003]);
+  assert.ok(progress.every((event) => event.payload.source === "agent-message-delta-progress" && event.payload.progress === true && event.payload.replyAuthority === false && event.payload.final === false));
+  const completed = events.find((event) => event.type === "assistant_message");
+  assert.equal(completed?.payload.source, "completed-agent-message");
+  assert.equal(completed?.payload.textBytes, 1_190);
+  assert.equal(events.some((event) => event.type === "assistant_message" && event.payload.source === "agent-message-delta-progress"), false);
+  const seal = events.find((event) => event.type === "backend_status" && event.payload.finalSeal === true);
+  assert.equal(seal?.payload.phase, "assistant-message-final-sealed");
+  assert.equal(Object.hasOwn(seal?.payload ?? {}, "text"), false);
+  assert.ok(events.some((event) => event.type === "terminal_status" && event.payload.terminalStatus === "completed"));
+
+  assert.throws(() => normalizeRunEventPayload("assistant_progress", {
+    text: "invalid authoritative progress",
+    source: "agent-message-delta-progress",
+    progress: true,
+    replyAuthority: true,
+    final: false,
+  }), /assistant_progress requires/u);
+}
+
+function notification(method: string, params: JsonRecord): JsonRecord {
+  return { jsonrpc: "2.0", method, params };
+}
+
 async function assertAnonymousGenerationFence(client: ManagerClient, context: SelfTestContext, managerUrl: string): Promise<void> {
   const command = await createRunWithCommand(client, context, "anonymous assistant generation fence", "selftest-assistant-anonymous-generation-fence", 15_000);
   const run = await runOnce({
@@ -71,7 +126,7 @@ async function assertAnonymousGenerationFence(client: ManagerClient, context: Se
   const completedMessages = events.filter((event) => event.type === "assistant_message" && event.payload.source === "completed-agent-message");
   assert.deepEqual(completedMessages.map((event) => event.payload.text), ["Anonymous first.", "Anonymous second final."], "new anonymous item/started must open a distinct legal generation");
   assert.ok(completedMessages.every((event) => event.payload.itemId === null));
-  const progressEvents = events.filter((event) => event.type === "assistant_message" && event.payload.source === "agent-message-delta-progress");
+  const progressEvents = events.filter((event) => event.type === "assistant_progress" && event.payload.source === "agent-message-delta-progress");
   assert.equal(progressEvents.length, 1, "only the reopened anonymous generation's live progress must remain visible");
   assert.equal(progressEvents[0]?.payload.progressFlush, false);
   assert.ok(progressEvents[0]!.seq < completedMessages[1]!.seq);
@@ -118,7 +173,7 @@ async function assertHistoryReplaySealedOnce(client: ManagerClient, context: Sel
   for (const itemId of ["msg_replay_progress", "msg_same_text_a", "msg_same_text_b", "msg_late_final_seal"]) {
     assert.equal(completedMessages.filter((event) => event.payload.itemId === itemId).length, 1, `item ${itemId} must be durable exactly once`);
   }
-  const progressEvents = events.filter((event) => event.type === "assistant_message" && event.payload.source === "agent-message-delta-progress");
+  const progressEvents = events.filter((event) => event.type === "assistant_progress" && event.payload.source === "agent-message-delta-progress");
   assert.ok(progressEvents.some((event) => event.payload.itemId === "msg_late_final_seal" && event.payload.progressFlush === false), "long assistant deltas must remain visible before completion");
   assert.equal(progressEvents.some((event) => event.payload.progressFlush === true), false, "completed item delta buffers must not be replayed by finalize()");
   for (const progress of progressEvents) {
@@ -126,6 +181,7 @@ async function assertHistoryReplaySealedOnce(client: ManagerClient, context: Sel
     assert.ok(completed && progress.seq < completed.seq, `item ${String(progress.payload.itemId)} progress must precede its durable completion`);
   }
   assert.equal(events.some((event) => event.type === "assistant_message" && typeof event.payload.text !== "string"), false, "bodyless control events must not be encoded as assistant messages");
+  assert.equal(events.some((event) => event.type === "assistant_message" && event.payload.source === "agent-message-delta-progress"), false, "live progress must not be encoded as an assistant message");
   const lateFinal = completedMessages.find((event) => event.payload.itemId === "msg_late_final_seal");
   assert.equal(lateFinal?.payload.text, lateFinalText, "the unique durable message body must remain untruncated for seal dereferencing");
   assert.equal(lateFinal?.payload.outputTruncated, false);