System events: add local timestamps in prompt injection

Closes #245

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Memory: allow custom OpenAI-compatible embedding endpoints for memory search (remote baseUrl/apiKey/headers). (#819 — thanks @mukhtharcm)
 
 ### Fixes
+- System events: include local timestamps when events are injected into prompts. (#245 — thanks @thewilloftheshadow)
 - Cron: accept `jobId` aliases for cron update/run/remove params in gateway validation. (#252 — thanks @thewilloftheshadow)
 - Models/Google: normalize Gemini 3 model ids to preview variants before runtime selection. (#795 — thanks @thewilloftheshadow)
 - TUI: keep the last streamed response instead of replacing it with “(no output)”. (#747 — thanks @thewilloftheshadow)

src/auto-reply/reply/session-updates.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it, vi } from "vitest";
+
+import type { ClawdbotConfig } from "../../config/config.js";
+import {
+  enqueueSystemEvent,
+  resetSystemEventsForTest,
+} from "../../infra/system-events.js";
+import { prependSystemEvents } from "./session-updates.js";
+
+describe("prependSystemEvents", () => {
+  it("adds a local timestamp to queued system events", async () => {
+    vi.useFakeTimers();
+    const timestamp = new Date("2026-01-12T20:19:17");
+    vi.setSystemTime(timestamp);
+
+    enqueueSystemEvent("Model switched.", { sessionKey: "agent:main:main" });
+
+    const result = await prependSystemEvents({
+      cfg: {} as ClawdbotConfig,
+      sessionKey: "agent:main:main",
+      isMainSession: false,
+      isNewSession: false,
+      prefixedBodyBase: "User: hi",
+    });
+
+    const expectedTimestamp = timestamp.toLocaleString("en-US", {
+      hour12: false,
+      year: "numeric",
+      month: "2-digit",
+      day: "2-digit",
+      hour: "2-digit",
+      minute: "2-digit",
+      second: "2-digit",
+    });
+
+    expect(result).toContain(
+      `System: [${expectedTimestamp}] Model switched.`,
+    );
+
+    resetSystemEventsForTest();
+    vi.useRealTimers();
+  });
+});

src/auto-reply/reply/session-updates.ts

@@ -4,7 +4,7 @@ import { buildWorkspaceSkillSnapshot } from "../../agents/skills.js";
 import type { ClawdbotConfig } from "../../config/config.js";
 import { type SessionEntry, saveSessionStore } from "../../config/sessions.js";
 import { buildProviderSummary } from "../../infra/provider-summary.js";
-import { drainSystemEvents } from "../../infra/system-events.js";
+import { drainSystemEventEntries } from "../../infra/system-events.js";
 
 export async function prependSystemEvents(params: {
   cfg: ClawdbotConfig;
@@ -25,10 +25,27 @@ export async function prependSystemEvents(params: {
     return trimmed;
   };
 
+  const formatSystemEventTimestamp = (ts: number) =>
+    new Date(ts).toLocaleString("en-US", {
+      hour12: false,
+      year: "numeric",
+      month: "2-digit",
+      day: "2-digit",
+      hour: "2-digit",
+      minute: "2-digit",
+      second: "2-digit",
+    });
+
   const systemLines: string[] = [];
-  const queued = drainSystemEvents(params.sessionKey);
+  const queued = drainSystemEventEntries(params.sessionKey);
   systemLines.push(
-    ...queued.map(compactSystemEvent).filter((v): v is string => Boolean(v)),
+    ...queued
+      .map((event) => {
+        const compacted = compactSystemEvent(event.text);
+        if (!compacted) return null;
+        return `[${formatSystemEventTimestamp(event.ts)}] ${compacted}`;
+      })
+      .filter((v): v is string => Boolean(v)),
   );
   if (params.isMainSession && params.isNewSession) {
     const summary = await buildProviderSummary(params.cfg);

src/infra/system-events.ts

@@ -2,7 +2,7 @@
 // prefixed to the next prompt. We intentionally avoid persistence to keep
 // events ephemeral. Events are session-scoped and require an explicit key.
 
-type SystemEvent = { text: string; ts: number };
+export type SystemEvent = { text: string; ts: number };
 
 const MAX_EVENTS = 20;
 
@@ -66,11 +66,11 @@ export function enqueueSystemEvent(text: string, options: SystemEventOptions) {
   if (entry.queue.length > MAX_EVENTS) entry.queue.shift();
 }
 
-export function drainSystemEvents(sessionKey: string): string[] {
+export function drainSystemEventEntries(sessionKey: string): SystemEvent[] {
   const key = requireSessionKey(sessionKey);
   const entry = queues.get(key);
   if (!entry || entry.queue.length === 0) return [];
-  const out = entry.queue.map((e) => e.text);
+  const out = entry.queue.slice();
   entry.queue.length = 0;
   entry.lastText = null;
   entry.lastContextKey = null;
@@ -78,6 +78,10 @@ export function drainSystemEvents(sessionKey: string): string[] {
   return out;
 }
 
+export function drainSystemEvents(sessionKey: string): string[] {
+  return drainSystemEventEntries(sessionKey).map((event) => event.text);
+}
+
 export function peekSystemEvents(sessionKey: string): string[] {
   const key = requireSessionKey(sessionKey);
   return queues.get(key)?.queue.map((e) => e.text) ?? [];