抽屉优化

db/schema.sql

@@ -697,6 +697,21 @@ CREATE TABLE IF NOT EXISTS skill_usage (
 CREATE INDEX IF NOT EXISTS idx_skill_usage_skill ON skill_usage(skill, ts DESC);
 CREATE INDEX IF NOT EXISTS idx_skill_usage_task  ON skill_usage(task_id);
 
+-- 工具调用账本（见 db/tool_usage.go）。一次实际 CoreTool.Call 一行，只记归属维度，
+-- 不保存工具参数或返回内容。刻意不设外键，任务、会话或自定义工具删除后仍保留统计。
+CREATE TABLE IF NOT EXISTS tool_usage (
+    id             BIGSERIAL PRIMARY KEY,
+    ts             TIMESTAMPTZ NOT NULL DEFAULT now(),
+    tool_key       TEXT NOT NULL,
+    agent_key      TEXT,
+    task_id        BIGINT,
+    exploration_id BIGINT,
+    intent_id      BIGINT,
+    session_id     TEXT
+);
+CREATE INDEX IF NOT EXISTS idx_tool_usage_tool ON tool_usage(tool_key, ts DESC);
+CREATE INDEX IF NOT EXISTS idx_tool_usage_task ON tool_usage(task_id);
+
 -- =====================================================================
 -- H. 内置工具目录
 -- =====================================================================