feat: add tool repetition monitoring to prevent infinite loops (#2527)

crates/goose/src/tool_monitor.rs

@@ -0,0 +1,74 @@
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ToolCall {
+    name: String,
+    parameters: serde_json::Value,
+}
+
+impl ToolCall {
+    pub fn new(name: String, parameters: serde_json::Value) -> Self {
+        Self { name, parameters }
+    }
+
+    fn matches(&self, other: &ToolCall) -> bool {
+        self.name == other.name && self.parameters == other.parameters
+    }
+}
+
+#[derive(Debug)]
+pub struct ToolMonitor {
+    max_repetitions: Option<u32>,
+    last_call: Option<ToolCall>,
+    repeat_count: u32,
+    call_counts: HashMap<String, u32>,
+}
+
+impl ToolMonitor {
+    pub fn new(max_repetitions: Option<u32>) -> Self {
+        Self {
+            max_repetitions,
+            last_call: None,
+            repeat_count: 0,
+            call_counts: HashMap::new(),
+        }
+    }
+
+    pub fn check_tool_call(&mut self, tool_call: ToolCall) -> bool {
+        let total_calls = self.call_counts.entry(tool_call.name.clone()).or_insert(0);
+        *total_calls += 1;
+
+        if self.max_repetitions.is_none() {
+            self.last_call = Some(tool_call);
+            self.repeat_count = 1;
+            return true;
+        }
+
+        if let Some(last) = &self.last_call {
+            if last.matches(&tool_call) {
+                self.repeat_count += 1;
+                if self.repeat_count > self.max_repetitions.unwrap() {
+                    return false;
+                }
+            } else {
+                self.repeat_count = 1;
+            }
+        } else {
+            self.repeat_count = 1;
+        }
+
+        self.last_call = Some(tool_call);
+        true
+    }
+
+    pub fn get_stats(&self) -> HashMap<String, u32> {
+        self.call_counts.clone()
+    }
+
+    pub fn reset(&mut self) {
+        self.last_call = None;
+        self.repeat_count = 0;
+        self.call_counts.clear();
+    }
+}