diff --git a/packages/server/src/server/agent/agent-sdk-types.ts b/packages/server/src/server/agent/agent-sdk-types.ts
index 46e694e89b..6570392311 100644
--- a/packages/server/src/server/agent/agent-sdk-types.ts
+++ b/packages/server/src/server/agent/agent-sdk-types.ts
@@ -314,7 +314,8 @@ export type ToolCallDetail =
       description?: string;
       childSessionId?: string;
       // COMPAT(subagent-log): added in v0.14.1, remove after 2027-04-30. Apps before v0.14.1
-      // require `log`; every producer sends it empty. Drop the field and those producers' `log: ""`.
+      // require `log`; every producer sends it empty and carries the same tag. Optional here because
+      // protocol timeline items, where `log` is optional, flow into this type.
       log?: string;
       actions?: Array<{
         index: number;
diff --git a/packages/server/src/server/agent/providers/claude/agent.ts b/packages/server/src/server/agent/providers/claude/agent.ts
index 3fa48c6c06..c675b1ed62 100644
--- a/packages/server/src/server/agent/providers/claude/agent.ts
+++ b/packages/server/src/server/agent/providers/claude/agent.ts
@@ -6276,6 +6276,7 @@ function buildClaudeSubagentCardDetail(
     type: "sub_agent",
     ...(facts.title ? { subAgentType: facts.title } : {}),
     ...(facts.description ? { description: facts.description } : {}),
+    // COMPAT(subagent-log): remove after 2027-04-30.
     log: "",
     actions: [],
   };
diff --git a/packages/server/src/server/agent/providers/claude/sidechain-tracker.ts b/packages/server/src/server/agent/providers/claude/sidechain-tracker.ts
index f0596c22fd..4e52ea9f50 100644
--- a/packages/server/src/server/agent/providers/claude/sidechain-tracker.ts
+++ b/packages/server/src/server/agent/providers/claude/sidechain-tracker.ts
@@ -137,6 +137,7 @@ export class ClaudeSidechainTracker {
       type: "sub_agent",
       ...(state.subAgentType ? { subAgentType: state.subAgentType } : {}),
       ...(state.description ? { description: state.description } : {}),
+      // COMPAT(subagent-log): remove after 2027-04-30.
       log: "",
       actions: [],
     };
diff --git a/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts b/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
index 64629bc5d9..4e77dc9367 100644
--- a/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
+++ b/packages/server/src/server/agent/providers/codex/tool-call-mapper.ts
@@ -950,6 +950,7 @@ function mapCollabAgentToolCallItem(
     type: "sub_agent",
     subAgentType: "Sub-agent",
     ...(item.prompt ? { description: item.prompt } : {}),
+    // COMPAT(subagent-log): remove after 2027-04-30.
     log: "",
     actions: [],
   };
@@ -1006,6 +1007,7 @@ function mapSubAgentActivityItem(
       type: "sub_agent",
       subAgentType: nativeName,
       description,
+      // COMPAT(subagent-log): remove after 2027-04-30.
       log: "",
       actions: [],
     },
diff --git a/packages/server/src/server/agent/providers/omp/tool-call-mapper.ts b/packages/server/src/server/agent/providers/omp/tool-call-mapper.ts
index 8610996814..500123758a 100644
--- a/packages/server/src/server/agent/providers/omp/tool-call-mapper.ts
+++ b/packages/server/src/server/agent/providers/omp/tool-call-mapper.ts
@@ -199,6 +199,7 @@ function mapOmpTaskDetail(args: unknown, result: OmpToolResult): ToolCallDetail
       argRecord.assignment,
     ),
     ...(childSessionId ? { childSessionId } : {}),
+    // COMPAT(subagent-log): remove after 2027-04-30.
     log: "",
   };
 }
diff --git a/packages/server/src/server/agent/providers/opencode/tool-call-detail-parser.ts b/packages/server/src/server/agent/providers/opencode/tool-call-detail-parser.ts
index f8f7b2bfd2..b3eb432f86 100644
--- a/packages/server/src/server/agent/providers/opencode/tool-call-detail-parser.ts
+++ b/packages/server/src/server/agent/providers/opencode/tool-call-detail-parser.ts
@@ -199,6 +199,7 @@ function deriveOpencodeTaskDetail(
     ...(subAgentType ? { subAgentType } : {}),
     ...(description ? { description } : {}),
     ...(childSessionId ? { childSessionId } : {}),
+    // COMPAT(subagent-log): remove after 2027-04-30.
     log: "",
     actions: [],
   };
diff --git a/packages/server/src/server/agent/providers/pi/extensions/edxeth-pi-subagents/index.ts b/packages/server/src/server/agent/providers/pi/extensions/edxeth-pi-subagents/index.ts
index 1b89c9407e..c58f0faf15 100644
--- a/packages/server/src/server/agent/providers/pi/extensions/edxeth-pi-subagents/index.ts
+++ b/packages/server/src/server/agent/providers/pi/extensions/edxeth-pi-subagents/index.ts
@@ -98,6 +98,7 @@ export const edxethPiSubagents: PiExtension = {
           detail: {
             type: "sub_agent",
             description,
+            // COMPAT(subagent-log): remove after 2027-04-30.
             log: "",
           },
           subagents,
diff --git a/packages/server/src/server/agent/providers/pi/extensions/gotgenes-pi-subagents/index.ts b/packages/server/src/server/agent/providers/pi/extensions/gotgenes-pi-subagents/index.ts
index 5eef7433da..7d1b4c325c 100644
--- a/packages/server/src/server/agent/providers/pi/extensions/gotgenes-pi-subagents/index.ts
+++ b/packages/server/src/server/agent/providers/pi/extensions/gotgenes-pi-subagents/index.ts
@@ -63,6 +63,7 @@ export const gotgenesPiSubagents: PiExtension = {
         type: "sub_agent" as const,
         subAgentType: title,
         description,
+        // COMPAT(subagent-log): remove after 2027-04-30.
         log: "",
       };
       if (call.status === "running")
@@ -117,6 +118,7 @@ export const gotgenesPiSubagents: PiExtension = {
       const detail = {
         type: "sub_agent" as const,
         description: details.success ? details.data.description : undefined,
+        // COMPAT(subagent-log): remove after 2027-04-30.
         log: "",
       };
       if (call.status === "running" || !details.success) return { detail };
diff --git a/packages/server/src/server/agent/providers/pi/extensions/pi-subagents/index.ts b/packages/server/src/server/agent/providers/pi/extensions/pi-subagents/index.ts
index 4ec882e11c..058171e8df 100644
--- a/packages/server/src/server/agent/providers/pi/extensions/pi-subagents/index.ts
+++ b/packages/server/src/server/agent/providers/pi/extensions/pi-subagents/index.ts
@@ -131,6 +131,7 @@ export const piSubagents: PiExtension = {
         type: "sub_agent" as const,
         subAgentType: args.data.agent,
         description: args.data.task,
+        // COMPAT(subagent-log): remove after 2027-04-30.
         log: "",
       };
       const base = {
diff --git a/packages/server/src/server/agent/providers/pi/extensions/subagent-fixture-test.ts b/packages/server/src/server/agent/providers/pi/extensions/subagent-fixture-test.ts
index 8a9ca61d08..96ba771594 100644
--- a/packages/server/src/server/agent/providers/pi/extensions/subagent-fixture-test.ts
+++ b/packages/server/src/server/agent/providers/pi/extensions/subagent-fixture-test.ts
@@ -54,8 +54,6 @@ export async function verifySubagentFixture(
   try {
     await session.startTurn("Delegate work");
     for (const event of fixture.events) pi.latestSession().emit(event);
-    const immediate = live.filter((event) => event.type === "provider_subagent");
-    expect(immediate.some((event) => event.event.type === "timeline")).toBe(false);
     pi.latestSession().finishTurn();
     const replay: AgentStreamEvent[] = [];
     for await (const event of streamPiHistory("pi", fixture.messages)) replay.push(event);
diff --git a/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.test.ts b/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.test.ts
index 65499183b8..60f3b12869 100644
--- a/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.test.ts
+++ b/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.test.ts
@@ -36,6 +36,11 @@ describe("@tintinweb/pi-subagents adapter", () => {
     });
     expect(mapping?.subagents).toEqual([
       expect.objectContaining({ id: "call-1", status: "completed" }),
+      {
+        type: "timeline",
+        id: "call-1",
+        item: { type: "assistant_message", text: "Wrapped up (turn limit)" },
+      },
     ]);
     expect(mapping?.detail).toEqual({
       type: "sub_agent",
@@ -53,6 +58,18 @@ describe("@tintinweb/pi-subagents adapter", () => {
         .filter((event) => event.event.type === "upsert")
         .map((event) => (event.event.type === "upsert" ? event.event.status : null)),
     ).toEqual(["running", "completed"]);
+    expect(
+      events.flatMap((event) => (event.event.type === "timeline" ? [event.event] : [])),
+    ).toEqual([
+      {
+        type: "timeline",
+        id: "call_458926",
+        item: {
+          type: "assistant_message",
+          text: "Agent completed in 6.6s (1 tool uses, 18.8k token).\n\nThe workspace directory `/tmp/paseo-pi-extension-phase3/workspace` is empty (no files or hidden dotfiles).",
+        },
+      },
+    ]);
   });
   test("uses a structured notification to complete a background child", async () => {
     const source = readSubagentFixture(new URL("./fixtures/background.json", import.meta.url));
diff --git a/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.ts b/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.ts
index 101035ad89..6858dec8be 100644
--- a/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.ts
+++ b/packages/server/src/server/agent/providers/pi/extensions/tintinweb-pi-subagents/index.ts
@@ -1,4 +1,5 @@
 import { z } from "zod";
+import { extractTextFromToolResult } from "../../tool-call-mapper.js";
 import { outputFileFromToolResult } from "../child-session.js";
 import type { PiExtension, PiExtensionToolCall } from "../contract.js";
 
@@ -56,6 +57,7 @@ export const tintinwebPiSubagents: PiExtension = {
         type: "sub_agent" as const,
         subAgentType: title,
         description,
+        // COMPAT(subagent-log): remove after 2027-04-30.
         log: "",
       };
       if (call.status === "running")
@@ -83,6 +85,10 @@ export const tintinwebPiSubagents: PiExtension = {
       const file = outputFileFromToolResult(call.result);
       const childSessions = file && !readSessions.has(file) ? [{ id: call.callId, file }] : [];
       if (file) readSessions.add(file);
+      const childStatus = status(details.data.status);
+      // A foreground child has no session file; its answer is the tool result.
+      const answer =
+        !file && childStatus !== "running" ? extractTextFromToolResult(call.result)?.trim() : "";
       return {
         detail,
         subagents: [
@@ -92,8 +98,17 @@ export const tintinwebPiSubagents: PiExtension = {
             title,
             description,
             toolCallId: call.callId,
-            status: status(details.data.status),
+            status: childStatus,
           },
+          ...(answer
+            ? [
+                {
+                  type: "timeline" as const,
+                  id: call.callId,
+                  item: { type: "assistant_message" as const, text: answer },
+                },
+              ]
+            : []),
         ],
         childSessions,
       };
@@ -109,6 +124,7 @@ export const tintinwebPiSubagents: PiExtension = {
       const detail = {
         type: "sub_agent" as const,
         description: details.success ? details.data.description : undefined,
+        // COMPAT(subagent-log): remove after 2027-04-30.
         log: "",
       };
       if (call.status === "running" || !details.success) return { detail };