diff --git a/extensions/codex/src/app-server/event-projector.ts b/extensions/codex/src/app-server/event-projector.ts
index 4212b1ad78c..9653d8aaf71 100644
--- a/extensions/codex/src/app-server/event-projector.ts
+++ b/extensions/codex/src/app-server/event-projector.ts
@@ -816,29 +816,24 @@ export class CodexAppServerEventProjector {
       typeof params.item.durationMs === "number" ? params.item.durationMs : undefined;
     const durationMs =
       itemDurationMs ?? (startedAt === undefined ? 0 : Math.max(0, Date.now() - startedAt));
-    if (params.status === "blocked") {
-      emitTrustedDiagnosticEvent({
-        type: "tool.execution.blocked",
-        ...base,
-        reason: "codex_native_tool_blocked",
-        deniedReason: "codex_native_tool_blocked",
-      });
-      return;
-    }
-    if (params.status === "failed") {
-      emitTrustedDiagnosticEvent({
-        type: "tool.execution.error",
-        ...base,
-        durationMs,
-        errorCategory: "codex_native_tool_error",
-      });
-      return;
-    }
-    emitTrustedDiagnosticEvent({
-      type: "tool.execution.completed",
-      ...base,
-      durationMs,
-    });
+    const terminalEvent =
+      params.status === "blocked"
+        ? {
+            type: "tool.execution.blocked" as const,
+            reason: "codex_native_tool_blocked",
+            deniedReason: "codex_native_tool_blocked",
+          }
+        : params.status === "failed"
+          ? {
+              type: "tool.execution.error" as const,
+              durationMs,
+              errorCategory: "codex_native_tool_error",
+            }
+          : {
+              type: "tool.execution.completed" as const,
+              durationMs,
+            };
+    emitTrustedDiagnosticEvent({ ...base, ...terminalEvent });
   }
 
   private emitToolResultSummary(item: CodexThreadItem | undefined): void {
diff --git a/src/logging/diagnostic-run-activity.ts b/src/logging/diagnostic-run-activity.ts
index 801f08e0882..adb3758c378 100644
--- a/src/logging/diagnostic-run-activity.ts
+++ b/src/logging/diagnostic-run-activity.ts
@@ -21,6 +21,11 @@ type ActiveTool = {
   lastProgressAt: number;
 };
 
+type DiagnosticToolStartedActivityEvent = Pick<
+  Extract<DiagnosticEventPayload, { type: "tool.execution.started" }>,
+  "runId" | "sessionId" | "sessionKey" | "toolName" | "toolCallId"
+>;
+
 export type DiagnosticSessionActivitySnapshot = {
   activeWorkKind?: DiagnosticSessionActiveWorkKind;
   activeToolName?: string;
@@ -158,9 +163,7 @@ function modelCallKey(event: { runId?: string; provider?: string; model?: string
   return `${event.runId ?? "unknown"}:${event.provider ?? "provider"}:${event.model ?? "model"}`;
 }
 
-function recordToolStarted(
-  event: Extract<DiagnosticEventPayload, { type: "tool.execution.started" }>,
-): void {
+function recordToolStarted(event: DiagnosticToolStartedActivityEvent): void {
   const activity = resolveSessionActivity({ ...event, create: true });
   if (!activity) {
     return;
@@ -314,18 +317,7 @@ export function markDiagnosticToolStartedForTest(params: {
   toolName: string;
   toolCallId?: string;
 }): void {
-  const activity = resolveSessionActivity({ ...params, create: true });
-  if (!activity) {
-    return;
-  }
-  const now = Date.now();
-  activity.activeTools.set(toolKey(params), {
-    toolName: params.toolName,
-    toolCallId: params.toolCallId,
-    startedAt: now,
-    lastProgressAt: now,
-  });
-  touchSessionActivity(activity, `tool:${params.toolName}:started`, now);
+  recordToolStarted(params);
 }
 
 export function resetDiagnosticRunActivityForTest(): void {