core/agent: tell the compact summarizer that tools are unavailable

src/plyngent/agent/compact.py

@@ -30,6 +30,8 @@ _SUMMARY_SYSTEM = (
     "Write a dense, factual summary that preserves: goals, decisions, "
     "file paths touched, commands run, open tasks, and constraints. "
     "Omit chit-chat and redundant tool dumps. Use short bullet sections. "
+    "Tool calls are unavailable in this request: do not call tools or emit "
+    "tool-call syntax; summarize only what the transcript contains. "
     "Do not invent facts not present in the transcript."
 )
 

tests/test_agent/test_compact_summarize.py

@@ -130,6 +130,15 @@ async def test_summarize_messages() -> None:
     assert "world" in user_msg.content
 
 
+async def test_summarize_default_prompt_says_tools_are_unavailable() -> None:
+    client = SummaryClient()
+    _ = await summarize_messages(client, [UserChatMessage(content="hi")], model="m")
+    assert client.last is not None
+    sys_msg = client.last.messages[0]
+    assert isinstance(sys_msg, SystemChatMessage)
+    assert "tool calls are unavailable" in sys_msg.content.lower()
+
+
 async def test_summarize_custom_prompts() -> None:
     client = SummaryClient()
     _ = await summarize_messages(