diff --git a/rust/src/lancedb_ops.rs b/rust/src/lancedb_ops.rs
index 8e98fc7..d14bd18 100644
--- a/rust/src/lancedb_ops.rs
+++ b/rust/src/lancedb_ops.rs
@@ -231,16 +231,71 @@ impl LanceDBOps {
 
     /// 更新记忆记录的字段（通过 SQL UPDATE）
     /// fields_json 格式: [{"column":"recall_count","value":"recall_count + 1"}, ...]
+    /// 支持算术表达式（value 包含 + 或 - 时），先查当前值再计算
     pub fn update(&self, table: &str, id: &str, fields_json: &str) -> Result<u64, Box<dyn std::error::Error>> {
         let db = rt().block_on(lancedb::connect(self.data_dir.to_str().unwrap()).execute())?;
         let tbl = rt().block_on(db.open_table(table).execute())?;
         let fields: Vec<serde_json::Value> = serde_json::from_str(fields_json)?;
         let mut op = tbl.update().only_if(format!("id = '{}'", id.replace('\'', "''")));
+
+        // 如果有算术表达式，先查当前值
+        let has_arith = fields.iter().any(|f| {
+            f["value"].as_str().map(|v| v.contains('+') || v.contains('-')).unwrap_or(false)
+        });
+
+        let mut current_values: std::collections::HashMap<String, i64> = std::collections::HashMap::new();
+        if has_arith {
+            // 查询当前值
+            let mut results = Box::pin(rt().block_on(
+                tbl.query()
+                    .only_if(&format!("id = '{}'", id.replace('\'', "''")))
+                    .limit(1)
+                    .execute(),
+            )?);
+            while let Some(Ok(batch)) = rt().block_on(results.next()) {
+                for i in 0..batch.num_rows() {
+                    for f in &fields {
+                        let col = f["column"].as_str().unwrap_or("");
+                        if !col.is_empty() {
+                            let val = col_i64(&batch, i, col);
+                            current_values.insert(col.to_string(), val);
+                        }
+                    }
+                }
+            }
+        }
+
         for f in &fields {
             let col = f["column"].as_str().unwrap_or("");
             let val = f["value"].as_str().unwrap_or("");
             if col.is_empty() { continue; }
-            op = op.column(col, val);
+
+            // 处理算术表达式: "column + N" 或 "column - N"
+            let final_val = if (val.contains('+') || val.contains('-')) && !val.starts_with('\'') {
+                let parts: Vec<&str> = val.split_whitespace().collect();
+                if parts.len() == 3 {
+                    let operand_col = parts[0];
+                    let op_char = parts[1].chars().next().unwrap_or('+');
+                    if let Ok(delta) = parts[2].parse::<i64>() {
+                        let current = *current_values.get(operand_col).unwrap_or(&0);
+                        let new_val = match op_char {
+                            '+' => current.saturating_add(delta),
+                            '-' => current.saturating_sub(delta),
+                            _ => current,
+                        };
+                        eprintln!("[lancedb] update {}: col={} expr={} current={} -> {}", id, col, val, current, new_val);
+                        new_val.to_string()
+                    } else {
+                        val.to_string()
+                    }
+                } else {
+                    val.to_string()
+                }
+            } else {
+                val.to_string()
+            };
+
+            op = op.column(col, &final_val);
         }
         let updated = rt().block_on(op.execute())?;
         eprintln!("[lancedb] update {}: id={} fields={} rows={}", table, id, fields.len(), updated);
diff --git a/rust/src/quality_backtrace.rs b/rust/src/quality_backtrace.rs
index 3c18344..28b927f 100644
--- a/rust/src/quality_backtrace.rs
+++ b/rust/src/quality_backtrace.rs
@@ -147,10 +147,17 @@ impl QualityBacktracer {
         let text = resp.text()?;
 
         let parsed: serde_json::Value = serde_json::from_str(&text)?;
-        let content = parsed["choices"][0]["message"]["content"]
+        let mut content = parsed["choices"][0]["message"]["content"]
             .as_str()
             .unwrap_or("")
             .to_string();
+        // MiniMax M2.7 uses reasoning_content for the actual response
+        if content.is_empty() {
+            content = parsed["choices"][0]["message"]["reasoning_content"]
+                .as_str()
+                .unwrap_or("")
+                .to_string();
+        }
 
         Ok(content)
     }