Merge remote-tracking branch 'origin/main'

# Conflicts:
#	nanobot/agent/tools/shell.py
#	tests/agent/test_evaluator.py
#	tests/channels/test_feishu_tool_hint_code_block.py
#	tests/providers/test_litellm_kwargs.py
#	tests/tools/test_web_search_tool.py

tests/agent/test_context_prompt_cache.py

@@ -0,0 +1,110 @@
+"""Tests for cache-friendly prompt construction."""
+
+from __future__ import annotations
+
+import datetime as datetime_module
+from datetime import datetime as real_datetime
+from importlib.resources import files as pkg_files
+from pathlib import Path
+
+from nanobot.agent.context import ContextBuilder
+
+
+class _FakeDatetime(real_datetime):
+    current = real_datetime(2026, 2, 24, 13, 59)
+
+    @classmethod
+    def now(cls, tz=None):  # type: ignore[override]
+        return cls.current
+
+
+def _make_workspace(tmp_path: Path) -> Path:
+    workspace = tmp_path / "workspace"
+    workspace.mkdir(parents=True)
+    return workspace
+
+
+def test_bootstrap_files_are_backed_by_templates() -> None:
+    template_dir = pkg_files("nanobot") / "templates"
+
+    for filename in ContextBuilder.BOOTSTRAP_FILES:
+        assert (template_dir / filename).is_file(), f"missing bootstrap template: {filename}"
+
+
+def test_system_prompt_stays_stable_when_clock_changes(tmp_path, monkeypatch) -> None:
+    """System prompt should not change just because wall clock minute changes."""
+    monkeypatch.setattr(datetime_module, "datetime", _FakeDatetime)
+
+    workspace = _make_workspace(tmp_path)
+    builder = ContextBuilder(workspace)
+
+    _FakeDatetime.current = real_datetime(2026, 2, 24, 13, 59)
+    prompt1 = builder.build_system_prompt()
+
+    _FakeDatetime.current = real_datetime(2026, 2, 24, 14, 0)
+    prompt2 = builder.build_system_prompt()
+
+    assert prompt1 == prompt2
+
+
+def test_system_prompt_mentions_workspace_out_for_generated_artifacts(tmp_path) -> None:
+    workspace = _make_workspace(tmp_path)
+    builder = ContextBuilder(workspace)
+
+    prompt = builder.build_system_prompt()
+
+    assert f"Put generated artifacts meant for delivery to the user under: {workspace}/out" in prompt
+    assert "Channels that need public URLs for local delivery artifacts expect files under " in prompt
+    assert "`mediaBaseUrl` at your own static file server for that directory." in prompt
+
+
+def test_runtime_context_is_separate_untrusted_user_message(tmp_path) -> None:
+    """Runtime metadata should be merged with the user message."""
+    workspace = _make_workspace(tmp_path)
+    builder = ContextBuilder(workspace)
+
+    messages = builder.build_messages(
+        history=[],
+        current_message="Return exactly: OK",
+        channel="cli",
+        chat_id="direct",
+    )
+
+    assert messages[0]["role"] == "system"
+    assert "## Current Session" not in messages[0]["content"]
+
+    # Runtime context is now merged with user message into a single message
+    assert messages[-1]["role"] == "user"
+    user_content = messages[-1]["content"]
+    assert isinstance(user_content, str)
+    assert ContextBuilder._RUNTIME_CONTEXT_TAG in user_content
+    assert "Current Time:" in user_content
+    assert "Channel: cli" in user_content
+    assert "Chat ID: direct" in user_content
+    assert "Return exactly: OK" in user_content
+
+
+def test_persona_prompt_uses_persona_overrides_and_memory(tmp_path: Path) -> None:
+    workspace = _make_workspace(tmp_path)
+    (workspace / "AGENTS.md").write_text("root agents", encoding="utf-8")
+    (workspace / "SOUL.md").write_text("root soul", encoding="utf-8")
+    (workspace / "USER.md").write_text("root user", encoding="utf-8")
+    (workspace / "memory").mkdir()
+    (workspace / "memory" / "MEMORY.md").write_text("root memory", encoding="utf-8")
+
+    persona_dir = workspace / "personas" / "coder"
+    persona_dir.mkdir(parents=True)
+    (persona_dir / "SOUL.md").write_text("coder soul", encoding="utf-8")
+    (persona_dir / "USER.md").write_text("coder user", encoding="utf-8")
+    (persona_dir / "memory").mkdir()
+    (persona_dir / "memory" / "MEMORY.md").write_text("coder memory", encoding="utf-8")
+
+    builder = ContextBuilder(workspace)
+    prompt = builder.build_system_prompt(persona="coder")
+
+    assert "Current persona: coder" in prompt
+    assert "root agents" in prompt
+    assert "coder soul" in prompt
+    assert "coder user" in prompt
+    assert "coder memory" in prompt
+    assert "root memory" not in prompt