"""工具输出防护示例 Skill。"""

from dataclasses import replace

from app.application.agent.extensions import (
    AfterToolCallDecision,
    AgentRunContext,
    ExtensionRegistry,
    ToolCallContext,
)
from app.application.agent.python_skills import PythonSkillDefinition
from app.modules.tool_runtime.definition import ToolResult

_MAX_OUTPUT_CHARS = 4000


async def _limit_tool_output(
    _call: ToolCallContext,
    result: ToolResult,
    _run: AgentRunContext,
) -> AfterToolCallDecision | None:
    if len(result.stdout) <= _MAX_OUTPUT_CHARS and len(result.stderr) <= _MAX_OUTPUT_CHARS:
        return None
    return AfterToolCallDecision(
        result=replace(
            result,
            stdout=result.stdout[:_MAX_OUTPUT_CHARS],
            stderr=result.stderr[:_MAX_OUTPUT_CHARS],
            truncated=True,
        )
    )


def _setup(registry: ExtensionRegistry) -> None:
    registry.add_after_tool_hook(_limit_tool_output)


SKILL = PythonSkillDefinition(
    name="response_guard",
    description="限制过长工具输出，避免无关内容挤占模型上下文。",
    triggers=("长输出", "大量输出", "response guard"),
    instructions="工具输出可能很长；优先分段读取，只保留完成当前任务所需的内容。",
    setup=_setup,
)