diff --git a/packages/agent/src/server/agent-server.test.ts b/packages/agent/src/server/agent-server.test.ts
index 9cbcdb8506..5d73535ab2 100644
--- a/packages/agent/src/server/agent-server.test.ts
+++ b/packages/agent/src/server/agent-server.test.ts
@@ -423,7 +423,11 @@ describe("AgentServer HTTP Mode", () => {
       const body = await response.json();
 
       expect(response.status).toBe(200);
-      expect(body).toEqual({ status: "ok", hasSession: true });
+      expect(body).toEqual({
+        status: "ok",
+        hasSession: true,
+        bootMs: expect.any(Number),
+      });
     }, 30000);
   });
 
diff --git a/packages/agent/src/server/agent-server.ts b/packages/agent/src/server/agent-server.ts
index 0c30dc5b14..c55c3f50bb 100644
--- a/packages/agent/src/server/agent-server.ts
+++ b/packages/agent/src/server/agent-server.ts
@@ -249,6 +249,7 @@ function getTaskRunStateString(
 
 export class AgentServer {
   private config: AgentServerConfig;
+  private sessionReadyBootMs?: number;
   private logger: Logger;
   private server: ServerType | null = null;
   private session: ActiveSession | null = null;
@@ -364,7 +365,11 @@ export class AgentServer {
     const app = new Hono();
 
     app.get("/health", (c) => {
-      return c.json({ status: "ok", hasSession: !!this.session });
+      return c.json({
+        status: "ok",
+        hasSession: !!this.session,
+        bootMs: this.sessionReadyBootMs,
+      });
     });
 
     app.get("/events", async (c) => {
@@ -558,6 +563,7 @@ export class AgentServer {
         () => {
           this.logger.debug(
             `HTTP server listening on port ${this.config.port}`,
+            { bootMs: Math.round(process.uptime() * 1000) },
           );
           resolve();
         },
@@ -1225,7 +1231,10 @@ export class AgentServer {
       },
     });
 
-    this.logger.debug("Session initialized successfully");
+    this.sessionReadyBootMs = Math.round(process.uptime() * 1000);
+    this.logger.debug("Session initialized successfully", {
+      bootMs: this.sessionReadyBootMs,
+    });
     this.logger.debug(
       `Agent version: ${this.config.version ?? packageJson.version}`,
     );