fix: normalize subagent skill prompts

Author: he-yufeng

astrbot/core/agent/agent.py

@@ -1,4 +1,4 @@
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any, Generic
 
 from .hooks import BaseAgentRunHooks
@@ -11,6 +11,6 @@ class Agent(Generic[TContext]):
     name: str
     instructions: str | None = None
     tools: list[str | FunctionTool] | None = None
-    skills: list[str] | None = field(default_factory=list)
+    skills: list[str] | None = None
     run_hooks: BaseAgentRunHooks[TContext] | None = None
     begin_dialogs: list[Any] | None = None

astrbot/core/astr_agent_tool_exec.py

@@ -305,11 +305,13 @@ def _build_handoff_system_prompt(
         skill_names: list[str] | None,
         runtime: str,
     ) -> str:
-        system_prompt = instructions or ""
         skills_prompt = cls._build_handoff_skills_prompt(skill_names, runtime)
-        if skills_prompt:
-            system_prompt += f"\n{skills_prompt}\n"
-        return system_prompt
+        parts = [
+            part.strip()
+            for part in (instructions, skills_prompt)
+            if isinstance(part, str) and part.strip()
+        ]
+        return "\n\n".join(parts)
 
     @classmethod
     def _build_handoff_skills_prompt(

tests/unit/test_astr_agent_tool_exec.py

@@ -438,7 +438,25 @@ async def _fake_tool_loop_agent(**kwargs):
         results.append(result)
 
     assert len(results) == 1
-    assert captured["system_prompt"] == "subagent-instructions\nSKILL PROMPT\n"
+    assert captured["system_prompt"] == "subagent-instructions\n\nSKILL PROMPT"
+
+
+def test_build_handoff_system_prompt_omits_empty_parts(
+    monkeypatch: pytest.MonkeyPatch,
+):
+    monkeypatch.setattr(
+        FunctionToolExecutor,
+        "_build_handoff_skills_prompt",
+        classmethod(lambda cls, skill_names, runtime: "SKILL PROMPT\n"),
+    )
+
+    prompt = FunctionToolExecutor._build_handoff_system_prompt(
+        "  ",
+        ["web-search-skill"],
+        "local",
+    )
+
+    assert prompt == "SKILL PROMPT"
 
 
 @pytest.mark.asyncio