diff --git a/Agent.md b/Agent.md
index 804f010a..c67ce4e3 100644
--- a/Agent.md
+++ b/Agent.md
@@ -118,7 +118,7 @@ Community needs voiced in HN agent-UI discussions map directly to EMRG's design:
 pkill -f "emrg.server"; rm -f ~/.emrg/emrgd.port; python -m emrg
 ```
 
-Python: `uv run pytest tests/ -v` (762) — import check: `uv run python -c "from emrg.client.app import run_client"`
+Python: `uv run pytest tests/ -v` (764) — import check: `uv run python -c "from emrg.client.app import run_client"`
 GUI: `cd emrg/gui && npm test` (231: 44 daemon_client + 19 conn-manager + 22 app-commands + 109 renderer smoke + 15 i18n + 7 integration + 3 commands + 5 build-config + 7 gui-state) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
 CI: `uv run pytest` (ubuntu + **windows-2025 matrix** — Windows pytest 回归在 PR CI 即失败，v0.2.29 教训 #725) + GUI tests + **actionlint workflow lint** (`rhysd/actionlint@v1.7.12` gate, #444 — workflow 解析错误在 PR CI 即失败，如 `if:` secrets 上下文)
 Re-trigger: `scripts/re-trigger-ci.sh [branch]` (workflow_dispatch, #527 — 替代空 commit 重触发：Actions outage 会整段丢弃 push 事件，dispatch 走 API 路径不受影响)
diff --git a/emrg/server/daemon.py b/emrg/server/daemon.py
index f3065331..5e41c28b 100644
--- a/emrg/server/daemon.py
+++ b/emrg/server/daemon.py
@@ -1038,6 +1038,11 @@ def _build_system_prompt(self, session: Session | None = None) -> str:
         """
         ctx: dict[str, Any] = {}
 
+        # ── Environment ──
+        ctx["current_time"] = datetime.now().astimezone().isoformat(timespec="seconds")
+        ctx["os_name"] = platform.system()
+        ctx["platform_detail"] = platform.platform()
+
         # ── Working Directory ──
         if session:
             ctx["working_dir"] = str(session.cwd)
diff --git a/emrg/server/prompts/system.j2 b/emrg/server/prompts/system.j2
index 88c86f4b..083d076a 100644
--- a/emrg/server/prompts/system.j2
+++ b/emrg/server/prompts/system.j2
@@ -11,6 +11,12 @@ You are EMRG, an evolving AI agent running as a micro-kernel daemon (emrgd). You
 - **write for new files**: use write for creating new files or full rewrites
 - **parallel calls**: when tools are independent, invoke them in parallel for speed
 
+{% if current_time %}
+**Current time**: `{{ current_time }}`
+{% endif %}
+{% if os_name %}
+**Operating system**: `{{ os_name }}` ({{ platform_detail }})
+{% endif %}
 {% if working_dir %}
 **Working directory**: `{{ working_dir }}`
 {% endif %}
diff --git a/tests/test_daemon.py b/tests/test_daemon.py
index fb22505d..0dfa8d50 100644
--- a/tests/test_daemon.py
+++ b/tests/test_daemon.py
@@ -9,7 +9,9 @@
 
 import asyncio
 import json
+import re
 import tempfile
+from datetime import datetime
 from pathlib import Path
 
 import yaml
@@ -225,6 +227,42 @@ def test_context_section_no_files(tmp_path):
     assert result == []
 
 
+def test_system_prompt_environment_time_and_os(tmp_path):
+    """system.j2 renders Current time + Operating system env info.
+
+    Rant 2026-08-13T14:01:46: agent must know "what time it is now"
+    (tz-aware local time, not UTC) and what platform it runs on.
+    """
+    server = _make_server()
+    session = Session.create_with_id("env-test", tmp_path)
+    rendered = server._build_system_prompt(session)
+
+    # Current time: tz-aware local ISO, seconds precision
+    assert "**Current time**: `" in rendered
+    m = re.search(r"\*\*Current time\*\*: `([^`]+)`", rendered)
+    assert m is not None
+    parsed = datetime.fromisoformat(m.group(1))
+    assert parsed.tzinfo is not None  # local tz-aware, never naive UTC
+
+    # OS name + platform detail present
+    assert "**Operating system**: `" in rendered
+    assert "Darwin" in rendered or "Windows" in rendered or "Linux" in rendered
+
+    # system.md debug output written
+    assert (session.dir_path / "system.md").exists()
+    md = (session.dir_path / "system.md").read_text(encoding="utf-8")
+    assert "Current time" in md and "Operating system" in md
+
+
+def test_system_prompt_environment_without_session(tmp_path):
+    """Env info renders even with no session (current_time/os always known)."""
+    server = _make_server()
+    rendered = server._build_system_prompt()
+    assert "**Current time**: `" in rendered
+    assert "**Operating system**: `" in rendered
+    assert "**Working directory**" not in rendered
+
+
 def test_context_section_single_file(tmp_path):
     """When CLAUDE.md exists, it's returned as a dict entry."""
     server = _make_server()