Emit goal changes as session metadata

src/CodexAcpServer.ts

@@ -13,6 +13,7 @@ import type {
     Model,
     ReasoningEffortOption,
     Thread,
+    ThreadGoalStatus,
     ThreadItem,
     TurnCompletedNotification,
     UserInput
@@ -69,7 +70,7 @@ import {resolveTerminalOutputMode, type TerminalOutputMode} from "./TerminalOutp
 
 export interface ThreadGoalSnapshot {
     objective: string;
-    status: string;
+    status: ThreadGoalStatus;
     tokenBudget: number | null;
 }
 

src/CodexEventHandler.ts

@@ -273,35 +273,9 @@ export class CodexEventHandler {
         }
         this.sessionState.currentGoal = goalSnapshot;
 
-        const status = this.formatThreadGoalStatus(event.goal.status);
-        const objective = goalSnapshot.objective;
-        const text = objective.includes("\n")
-            ? `Goal updated (${status}):\n${objective}`
-            : `Goal updated (${status}): ${objective}`;
-        return {
-            sessionUpdate: "agent_message_chunk",
-            content: {
-                type: "text",
-                text: `\n\n${text}\n\n`,
-            },
-        };
-    }
-
-    private formatThreadGoalStatus(status: ThreadGoalUpdatedNotification["goal"]["status"]): string {
-        switch (status) {
-            case "active":
-                return "active";
-            case "paused":
-                return "paused";
-            case "budgetLimited":
-                return "budget limited";
-            case "blocked":
-                return "blocked";
-            case "usageLimited":
-                return "usage limited";
-            case "complete":
-                return "complete";
-        }
+        return this.createCodexSessionInfoUpdate({
+            goal: goalSnapshot,
+        });
     }
 
     private createThreadGoalClearedEvent(_event: ThreadGoalClearedNotification): UpdateSessionEvent | null {
@@ -310,13 +284,9 @@ export class CodexEventHandler {
         }
         this.sessionState.currentGoal = null;
 
-        return {
-            sessionUpdate: "agent_message_chunk",
-            content: {
-                type: "text",
-                text: "\n\nGoal cleared.\n\n",
-            },
-        };
+        return this.createCodexSessionInfoUpdate({
+            goal: null,
+        });
     }
 
     private createThreadGoalSnapshot(event: ThreadGoalUpdatedNotification): ThreadGoalSnapshot {

src/__tests__/CodexACPAgent/CodexAcpClient.test.ts

@@ -1660,7 +1660,22 @@ describe('ACP server test', { timeout: 40_000 }, () => {
         await expect(promptPromise).resolves.toEqual(expect.objectContaining({
             stopReason: "end_turn",
         }));
-        expect(mockFixture.getAcpConnectionDump([])).toContain("Goal updated (active): Ship the migration and keep tests green");
+        expect(mockFixture.getAcpConnectionEvents([])).toContainEqual(expect.objectContaining({
+            args: [expect.objectContaining({
+                update: {
+                    sessionUpdate: "session_info_update",
+                    _meta: {
+                        codex: {
+                            goal: {
+                                objective: "Ship the migration and keep tests green",
+                                status: "active",
+                                tokenBudget: null,
+                            },
+                        },
+                    },
+                },
+            })],
+        }));
     });
 
     it('completes goal slash command when a turn routes after the goal update', async () => {

src/__tests__/CodexACPAgent/data/thread-goal-cleared.json

@@ -4,10 +4,11 @@
     {
       "sessionId": "test-session-id",
       "update": {
-        "sessionUpdate": "agent_message_chunk",
-        "content": {
-          "type": "text",
-          "text": "\n\nGoal cleared.\n\n"
+        "sessionUpdate": "session_info_update",
+        "_meta": {
+          "codex": {
+            "goal": null
+          }
         }
       }
     }

src/__tests__/CodexACPAgent/data/thread-goal-updated-multiline.json

@@ -4,10 +4,15 @@
     {
       "sessionId": "test-session-id",
       "update": {
-        "sessionUpdate": "agent_message_chunk",
-        "content": {
-          "type": "text",
-          "text": "\n\nGoal updated (budget limited):\nFirst task\nSecond task\n\n"
+        "sessionUpdate": "session_info_update",
+        "_meta": {
+          "codex": {
+            "goal": {
+              "objective": "First task\nSecond task",
+              "status": "budgetLimited",
+              "tokenBudget": 1000
+            }
+          }
         }
       }
     }

src/__tests__/CodexACPAgent/data/thread-goal-updated.json

@@ -4,10 +4,15 @@
     {
       "sessionId": "test-session-id",
       "update": {
-        "sessionUpdate": "agent_message_chunk",
-        "content": {
-          "type": "text",
-          "text": "\n\nGoal updated (active): Ship the goal update\n\n"
+        "sessionUpdate": "session_info_update",
+        "_meta": {
+          "codex": {
+            "goal": {
+              "objective": "Ship the goal update",
+              "status": "active",
+              "tokenBudget": null
+            }
+          }
         }
       }
     }

src/__tests__/CodexACPAgent/thread-goal-events.test.ts

@@ -18,7 +18,7 @@ describe("CodexEventHandler - thread goal events", () => {
         vi.clearAllMocks();
     });
 
-    it("should send thread goal updates as agent messages", async () => {
+    it("should send thread goal updates as session metadata", async () => {
         const goalUpdatedNotification: ServerNotification = {
             method: "thread/goal/updated",
             params: {
@@ -44,7 +44,7 @@ describe("CodexEventHandler - thread goal events", () => {
         );
     });
 
-    it("should format multiline thread goal updates", async () => {
+    it("should trim multiline thread goal objectives in session metadata", async () => {
         const goalUpdatedNotification: ServerNotification = {
             method: "thread/goal/updated",
             params: {
@@ -70,7 +70,7 @@ describe("CodexEventHandler - thread goal events", () => {
         );
     });
 
-    it("should send thread goal cleared as an agent message", async () => {
+    it("should send thread goal cleared as session metadata", async () => {
         const goalClearedNotification: ServerNotification = {
             method: "thread/goal/cleared",
             params: {
@@ -123,10 +123,21 @@ describe("CodexEventHandler - thread goal events", () => {
 
         const events = mockFixture.getAcpConnectionEvents([]);
         expect(events).toHaveLength(1);
-        expect(events[0]!.args[0].update.content.text).toBe("\n\nGoal updated (active): Ship the goal update\n\n");
+        expect(events[0]!.args[0].update).toEqual({
+            sessionUpdate: "session_info_update",
+            _meta: {
+                codex: {
+                    goal: {
+                        objective: "Ship the goal update",
+                        status: "active",
+                        tokenBudget: null,
+                    },
+                },
+            },
+        });
     });
 
-    it("should separate completed goal updates from preceding agent text", async () => {
+    it("should not append completed goal updates to preceding agent text", async () => {
         const goalCompletedNotification: ServerNotification = {
             method: "thread/goal/updated",
             params: {
@@ -160,7 +171,25 @@ describe("CodexEventHandler - thread goal events", () => {
 
         const events = mockFixture.getAcpConnectionEvents([]);
         expect(events).toHaveLength(2);
-        expect(events[1]!.args[0].update.content.text).toBe("\n\nGoal updated (complete): tell me a joke\n\n");
+        expect(events[0]!.args[0].update).toEqual({
+            sessionUpdate: "agent_message_chunk",
+            content: {
+                type: "text",
+                text: "Because they kept losing interest in `any`.",
+            },
+        });
+        expect(events[1]!.args[0].update).toEqual({
+            sessionUpdate: "session_info_update",
+            _meta: {
+                codex: {
+                    goal: {
+                        objective: "tell me a joke",
+                        status: "complete",
+                        tokenBudget: null,
+                    },
+                },
+            },
+        });
     });
 
     it("should suppress duplicate thread goal cleared notifications", async () => {
@@ -178,7 +207,14 @@ describe("CodexEventHandler - thread goal events", () => {
 
         const events = mockFixture.getAcpConnectionEvents([]);
         expect(events).toHaveLength(1);
-        expect(events[0]!.args[0].update.content.text).toBe("\n\nGoal cleared.\n\n");
+        expect(events[0]!.args[0].update).toEqual({
+            sessionUpdate: "session_info_update",
+            _meta: {
+                codex: {
+                    goal: null,
+                },
+            },
+        });
     });
 
     function createSessionState(): SessionState {