feat: 添加上下文压缩功能，优化消息历史管理和工具调用日志记录

.gitignore

@@ -2,3 +2,6 @@
 reference/**
 .env
 *.env
+AGENTS.md
+CLAUDE.md
+Cargo.lock

Cargo.toml

@@ -26,3 +26,4 @@ anyhow = "1.0"
 mime_guess = "2.0"
 base64 = "0.22"
 tempfile = "3"
+meval = "0.2"

src/agent/agent_loop.rs

@@ -330,6 +330,13 @@ impl AgentLoop {
             let tool_results = self.execute_tools(&response.tool_calls).await;
 
             for (tool_call, result) in response.tool_calls.iter().zip(tool_results.iter()) {
+                // Log function call with name and arguments
+                let args_str = match &tool_call.arguments {
+                    serde_json::Value::Object(obj) if obj.is_empty() => "{}".to_string(),
+                    other => serde_json::to_string_pretty(other).unwrap_or_else(|_| other.to_string()),
+                };
+                tracing::info!(tool = %tool_call.name, args = %args_str, "Calling tool");
+
                 // Truncate tool result if too large
                 let truncated_output = truncate_tool_result(&result.output);
 

src/agent/context_compressor.rs

@@ -0,0 +1,372 @@
+use crate::bus::ChatMessage;
+use crate::config::LLMProviderConfig;
+use crate::providers::{create_provider, ChatCompletionRequest, Message};
+
+use crate::agent::AgentError;
+
+/// Token estimation using ~4 chars/token heuristic with 1.2x safety margin.
+pub fn estimate_tokens(messages: &[ChatMessage]) -> usize {
+    let raw: usize = messages
+        .iter()
+        .map(|m| m.content.len().div_ceil(4) + 4)
+        .sum();
+    (raw as f64 * 1.2) as usize
+}
+
+/// Configuration for context compression.
+#[derive(Debug, Clone)]
+pub struct ContextCompressionConfig {
+    /// Protect first N messages (system prompt, etc.)
+    pub protect_first_n: usize,
+    /// Protect last N messages (recent context)
+    pub protect_last_n: usize,
+    /// Maximum compression passes
+    pub max_passes: u32,
+    /// Maximum characters in summary
+    pub summary_max_chars: usize,
+    /// Characters to keep when trimming tool results
+    pub tool_result_trim_chars: usize,
+}
+
+impl Default for ContextCompressionConfig {
+    fn default() -> Self {
+        Self {
+            protect_first_n: 1,
+            protect_last_n: 4,
+            max_passes: 3,
+            summary_max_chars: 4000,
+            tool_result_trim_chars: 2000,
+        }
+    }
+}
+
+/// Context compressor that reduces message history when it exceeds token limits.
+pub struct ContextCompressor {
+    config: ContextCompressionConfig,
+    context_window: usize,
+    /// Threshold ratio to trigger compression (50% of context window)
+    threshold_ratio: f64,
+}
+
+impl ContextCompressor {
+    /// Create a new compressor with the given context window size.
+    pub fn new(context_window: usize) -> Self {
+        Self {
+            config: ContextCompressionConfig::default(),
+            context_window,
+            threshold_ratio: 0.5,
+        }
+    }
+
+    /// Create with custom configuration.
+    pub fn with_config(context_window: usize, config: ContextCompressionConfig) -> Self {
+        Self {
+            config,
+            context_window,
+            threshold_ratio: 0.5,
+        }
+    }
+
+    /// Get the compression threshold in tokens.
+    fn threshold(&self) -> usize {
+        (self.context_window as f64 * self.threshold_ratio) as usize
+    }
+
+    /// Fast-path: trim oversized tool results without LLM call.
+    /// Returns the number of messages modified.
+    fn fast_trim_tool_results(&self, messages: &mut [ChatMessage]) -> usize {
+        let limit = self.config.tool_result_trim_chars;
+        let mut modified = 0;
+
+        for msg in messages.iter_mut() {
+            if msg.role == "tool" && msg.content.len() > limit {
+                let removed = msg.content.len() - limit;
+                msg.content = format!(
+                    "{}...\n\n[Output truncated - {} characters removed]",
+                    &msg.content[..limit.min(msg.content.len())],
+                    removed
+                );
+                modified += 1;
+            }
+        }
+
+        modified
+    }
+
+    /// Main entry point - compresses history if over threshold.
+    pub async fn compress_if_needed(
+        &self,
+        history: Vec<ChatMessage>,
+        provider_config: &LLMProviderConfig,
+    ) -> Result<Vec<ChatMessage>, AgentError> {
+        // Check if compression is needed
+        let tokens = estimate_tokens(&history);
+        if tokens <= self.threshold() {
+            #[cfg(debug_assertions)]
+            tracing::info!(
+                tokens = tokens,
+                threshold = self.threshold(),
+                msg_count = history.len(),
+                "Context compression not needed"
+            );
+            return Ok(history);
+        }
+
+        tracing::info!(
+            tokens = tokens,
+            threshold = self.threshold(),
+            msg_count = history.len(),
+            "Starting context compression"
+        );
+
+        // Fast trim pass first
+        let trimmed = self.fast_trim_tool_results(&mut history.clone());
+        if trimmed > 0 {
+            let tokens_after = estimate_tokens(&history);
+            #[cfg(debug_assertions)]
+            tracing::debug!(
+                trimmed_messages = trimmed,
+                tokens_after = tokens_after,
+                "Fast trim completed"
+            );
+            if tokens_after <= self.threshold() {
+                return Ok(history);
+            }
+        }
+
+        // LLM summarization pass
+        let mut current_history = history;
+        for pass in 0..self.config.max_passes {
+            let tokens = estimate_tokens(&current_history);
+            if tokens <= self.threshold() {
+                break;
+            }
+
+            #[cfg(debug_assertions)]
+            tracing::debug!(
+                pass = pass + 1,
+                tokens = tokens,
+                "Compression pass"
+            );
+
+            match self.compress_once(&current_history, provider_config).await {
+                Ok(Some(compressed)) => {
+                    current_history = compressed;
+                }
+                Ok(None) => {
+                    // No more compressible content
+                    break;
+                }
+                Err(e) => {
+                    tracing::warn!(error = %e, "Compression pass failed, using current history");
+                    break;
+                }
+            }
+        }
+
+        tracing::info!(
+            final_tokens = estimate_tokens(&current_history),
+            final_msg_count = current_history.len(),
+            "Context compression completed"
+        );
+
+        Ok(current_history)
+    }
+
+    /// Single compression pass - summarize middle messages between user turns.
+    /// Returns Some(compressed) if compression happened, None if nothing to compress.
+    async fn compress_once(
+        &self,
+        history: &[ChatMessage],
+        provider_config: &LLMProviderConfig,
+    ) -> Result<Option<Vec<ChatMessage>>, AgentError> {
+        if history.len() <= self.config.protect_first_n + self.config.protect_last_n {
+            return Ok(None);
+        }
+
+        // Find user message indices (excluding protected first messages)
+        let user_indices: Vec<usize> = history
+            .iter()
+            .enumerate()
+            .skip(self.config.protect_first_n)
+            .filter(|(_, m)| m.role == "user")
+            .map(|(i, _)| i)
+            .collect();
+
+        // Need at least one user message and content between users to compress
+        if user_indices.len() < 2 {
+            return Ok(None);
+        }
+
+        // Build segments: user -> (assistant turns) -> next user
+        // We'll summarize the assistant turns between consecutive user messages
+        let mut new_messages = history[..=user_indices[0]].to_vec();
+
+        for i in 0..user_indices.len() - 1 {
+            let user_idx = user_indices[i];
+            let next_user_idx = user_indices[i + 1];
+
+            new_messages.push(history[user_idx].clone());
+
+            // Check if there's assistant content between these two user messages
+            let between_start = user_idx + 1;
+            let between_end = next_user_idx;
+
+            if between_start < between_end {
+                let between = &history[between_start..between_end];
+                let summary = self.summarize_segment(between, provider_config).await?;
+
+                // Add summary as a special user message
+                new_messages.push(ChatMessage::user(format!(
+                    "[Context Summary]\n\n{}",
+                    summary
+                )));
+            }
+        }
+
+        // Add last user and everything after (protected)
+        let last_user_idx = user_indices[user_indices.len() - 1];
+        if last_user_idx < history.len() - 1 {
+            // Add everything from last user onwards (protected)
+            for i in last_user_idx..history.len() {
+                new_messages.push(history[i].clone());
+            }
+        }
+
+        // If nothing changed, return None
+        if new_messages.len() == history.len() {
+            return Ok(None);
+        }
+
+        Ok(Some(new_messages))
+    }
+
+    /// Summarize a segment of messages using LLM.
+    async fn summarize_segment(
+        &self,
+        messages: &[ChatMessage],
+        provider_config: &LLMProviderConfig,
+    ) -> Result<String, AgentError> {
+        if messages.is_empty() {
+            return Ok(String::new());
+        }
+
+        // Build transcript for summarization
+        let transcript = messages
+            .iter()
+            .map(|m| {
+                let role = match m.role.as_str() {
+                    "assistant" => "Assistant",
+                    "tool" => "Tool",
+                    _ => m.role.as_str(),
+                };
+                let name = m.tool_name
+                    .as_ref()
+                    .map(|n| format!(" ({})", n))
+                    .unwrap_or_default();
+                format!("{}: {}{}", role, m.content, name)
+            })
+            .collect::<Vec<_>>()
+            .join("\n\n");
+
+        // Truncate transcript if too long
+        let transcript = if transcript.len() > self.config.summary_max_chars {
+            format!(
+                "{}...\n\n[Transcript truncated - {} characters removed]",
+                &transcript[..self.config.summary_max_chars],
+                transcript.len() - self.config.summary_max_chars
+            )
+        } else {
+            transcript
+        };
+
+        let prompt = format!(
+            r#"You are a conversation compaction engine. Summarize the following conversation segment.
+
+PRESERVE:
+- All identifiers (UUIDs, hashes, file paths, URLs)
+- Actions taken (tool calls, file operations, commands)
+- Key information obtained (results, data, errors)
+- Decisions and user preferences
+- Current task status
+
+OMIT:
+- Verbose tool output (keep key results only)
+- Repeated greetings or filler
+
+Be concise, aim for {} characters or less.
+
+---
+
+{}
+
+"#,
+            self.config.summary_max_chars, transcript
+        );
+
+        // Create provider and call LLM
+        let provider = create_provider(provider_config.clone())
+            .map_err(|e| AgentError::ProviderCreation(e.to_string()))?;
+
+        let request = ChatCompletionRequest {
+            messages: vec![Message::system("You are a helpful assistant."), Message::user(&prompt)],
+            temperature: Some(0.3),
+            max_tokens: Some(1000),
+            tools: None,
+        };
+
+        match provider.chat(request).await {
+            Ok(response) => Ok(response.content),
+            Err(e) => {
+                // Fallback: just truncate the transcript
+                tracing::warn!(error = %e, "LLM summarization failed, using truncated transcript");
+                Ok(transcript[..transcript.len().min(2000)].to_string())
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_estimate_tokens() {
+        let messages = vec![
+            ChatMessage::user("Hello"),
+            ChatMessage::assistant("Hi there!"),
+            ChatMessage::user("How are you?"),
+        ];
+
+        let tokens = estimate_tokens(&messages);
+        // "Hello" (5) -> ceil(5/4)+4 = 2+4 = 6
+        // "Hi there!" (8) -> ceil(8/4)+4 = 2+4 = 6
+        // "How are you?" (11) -> ceil(11/4)+4 = 3+4 = 7
+        // raw = 19, with 1.2x = ~23
+        assert!(tokens > 18 && tokens < 30, "Expected ~23 tokens, got {}", tokens);
+    }
+
+    #[test]
+    fn test_fast_trim() {
+        let config = ContextCompressionConfig {
+            tool_result_trim_chars: 50,
+            ..Default::default()
+        };
+        let compressor = ContextCompressor::with_config(100_000, config);
+
+        let mut messages = vec![
+            ChatMessage::user("Hello"),
+            ChatMessage::tool("call1", "bash", &"x".repeat(200)),
+        ];
+
+        let modified = compressor.fast_trim_tool_results(&mut messages);
+        assert_eq!(modified, 1);
+        assert!(messages[1].content.len() < 100);
+    }
+
+    #[test]
+    fn test_threshold() {
+        let compressor = ContextCompressor::new(128_000);
+        assert_eq!(compressor.threshold(), 64_000);
+    }
+}

src/agent/mod.rs

@@ -1,3 +1,5 @@
 pub mod agent_loop;
+pub mod context_compressor;
 
 pub use agent_loop::{AgentLoop, AgentError};
+pub use context_compressor::ContextCompressor;

src/config/mod.rs

@@ -75,12 +75,18 @@ pub struct AgentConfig {
     pub model: String,
     #[serde(default = "default_max_tool_iterations")]
     pub max_tool_iterations: usize,
+    #[serde(default = "default_token_limit")]
+    pub token_limit: usize,
 }
 
 fn default_max_tool_iterations() -> usize {
     20
 }
 
+fn default_token_limit() -> usize {
+    128_000
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct GatewayConfig {
     #[serde(default = "default_gateway_host")]
@@ -139,6 +145,7 @@ pub struct LLMProviderConfig {
     pub max_tokens: Option<u32>,
     pub model_extra: HashMap<String, serde_json::Value>,
     pub max_tool_iterations: usize,
+    pub token_limit: usize,
 }
 
 fn get_default_config_path() -> PathBuf {
@@ -199,6 +206,7 @@ impl Config {
             max_tokens: model.max_tokens,
             model_extra: model.extra.clone(),
             max_tool_iterations: agent.max_tool_iterations,
+            token_limit: agent.token_limit,
         })
     }
 }

src/gateway/session.rs

@@ -5,7 +5,7 @@ use tokio::sync::{Mutex, mpsc};
 use uuid::Uuid;
 use crate::bus::ChatMessage;
 use crate::config::LLMProviderConfig;
-use crate::agent::{AgentLoop, AgentError};
+use crate::agent::{AgentLoop, AgentError, ContextCompressor};
 use crate::protocol::WsOutbound;
 use crate::tools::{
     BashTool, CalculatorTool, FileEditTool, FileReadTool, FileWriteTool,
@@ -22,6 +22,7 @@ pub struct Session {
     pub user_tx: mpsc::Sender<WsOutbound>,
     provider_config: LLMProviderConfig,
     tools: Arc<ToolRegistry>,
+    compressor: ContextCompressor,
 }
 
 impl Session {
@@ -36,8 +37,9 @@ impl Session {
             channel_name,
             chat_histories: HashMap::new(),
             user_tx,
-            provider_config,
+            provider_config: provider_config.clone(),
             tools,
+            compressor: ContextCompressor::new(provider_config.token_limit),
         })
     }
 
@@ -94,6 +96,16 @@ impl Session {
         let _ = self.user_tx.send(msg).await;
     }
 
+    /// 获取 provider_config 引用
+    pub fn provider_config(&self) -> &LLMProviderConfig {
+        &self.provider_config
+    }
+
+    /// 获取 compressor 引用
+    pub fn compressor(&self) -> &ContextCompressor {
+        &self.compressor
+    }
+
     /// 创建一个临时的 AgentLoop 实例来处理消息
     pub fn create_agent(&self) -> Result<AgentLoop, AgentError> {
         AgentLoop::with_tools(self.provider_config.clone(), self.tools.clone())
@@ -252,6 +264,11 @@ impl SessionManager {
             // 获取完整历史
             let history = session_guard.get_or_create_history(chat_id).clone();
 
+            // 压缩历史（如果需要）
+            let history = session_guard.compressor
+                .compress_if_needed(history, &session_guard.provider_config)
+                .await?;
+
             // 创建 agent 并处理
             let agent = session_guard.create_agent()?;
             let response = agent.process(history).await?;

src/gateway/ws.rs

@@ -130,6 +130,18 @@ async fn handle_inbound(session: &Arc<Mutex<Session>>, inbound: WsInbound) {
     // 获取完整历史
     let history = session_guard.get_or_create_history(&chat_id).clone();
 
+    // 压缩历史（如果需要）
+    let history = match session_guard.compressor()
+        .compress_if_needed(history, session_guard.provider_config())
+        .await
+    {
+        Ok(h) => h,
+        Err(e) => {
+            tracing::warn!(chat_id = %chat_id, error = %e, "Compression failed, using original history");
+            session_guard.get_or_create_history(&chat_id).clone()
+        }
+    };
+
     // 创建 agent 并处理
     let agent = match session_guard.create_agent() {
         Ok(a) => a,

src/tools/calculator.rs

@@ -23,9 +23,8 @@ impl Tool for CalculatorTool {
     }
 
     fn description(&self) -> &str {
-        "Perform arithmetic and statistical calculations. Supports 25 functions: \
+        "Perform arithmetic and statistical calculations. Supports expression evaluation (evaluate) and functions: \
-         add, subtract, divide, multiply, pow, sqrt, abs, modulo, round, \
+         round, log, factorial, sum, average, median, mode, min, max, \
-         log, ln, exp, factorial, sum, average, median, mode, min, max, \
          range, variance, stdev, percentile, count, percentage_change, clamp. \
          Use this tool whenever you need to compute a numeric result instead of guessing."
     }
@@ -41,35 +40,36 @@ impl Tool for CalculatorTool {
                 "function": {
                     "type": "string",
                     "description": "Calculation to perform. \
-                        Arithmetic: add(values), subtract(values), divide(values), multiply(values), pow(a,b), sqrt(x), abs(x), modulo(a,b), round(x,decimals). \
+                        Expression: evaluate(expression) - supports +, -, *, /, %, ^, parentheses, and functions like sqrt, abs, exp, ln, sin, cos, tan, round, floor, ceil, max, min, etc. \
-                        Logarithmic/exponential: log(x,base?), ln(x), exp(x), factorial(x). \
+                        Rounding: round(x, decimals). \
+                        Logarithmic: log(x, base?) - base defaults to 10. \
+                        Special: factorial(x). \
                         Aggregation: sum(values), average(values), count(values), min(values), max(values), range(values). \
                         Statistics: median(values), mode(values), variance(values), stdev(values), percentile(values,p). \
                         Utility: percentage_change(a,b), clamp(x,min_val,max_val).",
                     "enum": [
-                        "add", "subtract", "divide", "multiply", "pow", "sqrt",
+                        "round", "log", "factorial",
-                        "abs", "modulo", "round", "log", "ln", "exp", "factorial",
                         "sum", "average", "median", "mode", "min", "max", "range",
                         "variance", "stdev", "percentile", "count",
-                        "percentage_change", "clamp"
+                        "percentage_change", "clamp", "evaluate"
                     ]
                 },
                 "values": {
                     "type": "array",
                     "items": { "type": "number" },
-                    "description": "Array of numeric values. Required for: add, subtract, divide, multiply, sum, average, median, mode, min, max, range, variance, stdev, percentile, count."
+                    "description": "Array of numeric values. Required for: sum, average, median, mode, min, max, range, variance, stdev, percentile, count."
                 },
                 "a": {
                     "type": "number",
-                    "description": "First operand. Required for: pow, modulo, percentage_change."
+                    "description": "First operand. Required for: percentage_change."
                 },
                 "b": {
                     "type": "number",
-                    "description": "Second operand. Required for: pow, modulo, percentage_change."
+                    "description": "Second operand. Required for: percentage_change."
                 },
                 "x": {
                     "type": "number",
-                    "description": "Input number. Required for: sqrt, abs, exp, ln, log, factorial."
+                    "description": "Input number. Required for: log, factorial, round, clamp."
                 },
                 "base": {
                     "type": "number",
@@ -90,6 +90,10 @@ impl Tool for CalculatorTool {
                 "max_val": {
                     "type": "number",
                     "description": "Maximum bound. Required for: clamp."
+                },
+                "expression": {
+                    "type": "string",
+                    "description": "Mathematical expression to evaluate. Supports: +, -, *, /, %, ^ (power), parentheses. Functions: sqrt, abs, exp, ln, sin, cos, tan, asin, acos, atan, atan2, sinh, cosh, tanh, asinh, acosh, atanh, floor, ceil, round, signum, max, min. Constants: pi, e. Variables: x, weight, etc. Example: '15*3+5^(2+1)', 'sin(pi/2)', 'max(1,2,3)'"
                 }
             },
             "required": ["function"]
@@ -109,18 +113,8 @@ impl Tool for CalculatorTool {
         };
 
         let result = match function {
-            "add" => calc_add(&args),
-            "subtract" => calc_subtract(&args),
-            "divide" => calc_divide(&args),
-            "multiply" => calc_multiply(&args),
-            "pow" => calc_pow(&args),
-            "sqrt" => calc_sqrt(&args),
-            "abs" => calc_abs(&args),
-            "modulo" => calc_modulo(&args),
             "round" => calc_round(&args),
             "log" => calc_log(&args),
-            "ln" => calc_ln(&args),
-            "exp" => calc_exp(&args),
             "factorial" => calc_factorial(&args),
             "sum" => calc_sum(&args),
             "average" => calc_average(&args),
@@ -135,6 +129,7 @@ impl Tool for CalculatorTool {
             "count" => calc_count(&args),
             "percentage_change" => calc_percentage_change(&args),
             "clamp" => calc_clamp(&args),
+            "evaluate" => calc_evaluate(&args),
             other => Err(format!("Unknown function: {other}")),
         };
 
@@ -196,71 +191,6 @@ fn format_num(n: f64) -> String {
     }
 }
 
-fn calc_add(args: &serde_json::Value) -> Result<String, String> {
-    let values = extract_values(args, 2)?;
-    Ok(format_num(values.iter().sum()))
-}
-
-fn calc_subtract(args: &serde_json::Value) -> Result<String, String> {
-    let values = extract_values(args, 2)?;
-    let mut iter = values.iter();
-    let mut result = *iter.next().unwrap();
-    for v in iter {
-        result -= v;
-    }
-    Ok(format_num(result))
-}
-
-fn calc_divide(args: &serde_json::Value) -> Result<String, String> {
-    let values = extract_values(args, 2)?;
-    let mut iter = values.iter();
-    let mut result = *iter.next().unwrap();
-    for v in iter {
-        if *v == 0.0 {
-            return Err("Division by zero".to_string());
-        }
-        result /= v;
-    }
-    Ok(format_num(result))
-}
-
-fn calc_multiply(args: &serde_json::Value) -> Result<String, String> {
-    let values = extract_values(args, 2)?;
-    let mut result = 1.0;
-    for v in &values {
-        result *= v;
-    }
-    Ok(format_num(result))
-}
-
-fn calc_pow(args: &serde_json::Value) -> Result<String, String> {
-    let base = extract_f64(args, "a", "a (base)")?;
-    let exp = extract_f64(args, "b", "b (exponent)")?;
-    Ok(format_num(base.powf(exp)))
-}
-
-fn calc_sqrt(args: &serde_json::Value) -> Result<String, String> {
-    let x = extract_f64(args, "x", "x")?;
-    if x < 0.0 {
-        return Err("Cannot compute square root of a negative number".to_string());
-    }
-    Ok(format_num(x.sqrt()))
-}
-
-fn calc_abs(args: &serde_json::Value) -> Result<String, String> {
-    let x = extract_f64(args, "x", "x")?;
-    Ok(format_num(x.abs()))
-}
-
-fn calc_modulo(args: &serde_json::Value) -> Result<String, String> {
-    let a = extract_f64(args, "a", "a")?;
-    let b = extract_f64(args, "b", "b")?;
-    if b == 0.0 {
-        return Err("Modulo by zero".to_string());
-    }
-    Ok(format_num(a % b))
-}
-
 fn calc_round(args: &serde_json::Value) -> Result<String, String> {
     let x = extract_f64(args, "x", "x")?;
     let decimals = extract_i64(args, "decimals", "decimals")?;
@@ -283,19 +213,6 @@ fn calc_log(args: &serde_json::Value) -> Result<String, String> {
     Ok(format_num(x.log(base)))
 }
 
-fn calc_ln(args: &serde_json::Value) -> Result<String, String> {
-    let x = extract_f64(args, "x", "x")?;
-    if x <= 0.0 {
-        return Err("Natural logarithm requires a positive number".to_string());
-    }
-    Ok(format_num(x.ln()))
-}
-
-fn calc_exp(args: &serde_json::Value) -> Result<String, String> {
-    let x = extract_f64(args, "x", "x")?;
-    Ok(format_num(x.exp()))
-}
-
 fn calc_factorial(args: &serde_json::Value) -> Result<String, String> {
     let x = extract_f64(args, "x", "x")?;
     if x < 0.0 || x != x.floor() {
@@ -457,119 +374,21 @@ fn calc_clamp(args: &serde_json::Value) -> Result<String, String> {
     Ok(format_num(x.clamp(min_val, max_val)))
 }
 
+fn calc_evaluate(args: &serde_json::Value) -> Result<String, String> {
+    let expression = args
+        .get("expression")
+        .and_then(|v| v.as_str())
+        .ok_or_else(|| "Missing required parameter: expression".to_string())?;
+
+    meval::eval_str(expression)
+        .map(format_num)
+        .map_err(|e| format!("Expression evaluation error: {e}"))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    #[tokio::test]
-    async fn test_add() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "add", "values": [1.0, 2.0, 3.5]}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "6.5");
-    }
-
-    #[tokio::test]
-    async fn test_subtract() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "subtract", "values": [10.0, 3.0, 1.5]}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "5.5");
-    }
-
-    #[tokio::test]
-    async fn test_divide() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "divide", "values": [100.0, 4.0]}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "25");
-    }
-
-    #[tokio::test]
-    async fn test_divide_by_zero() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "divide", "values": [10.0, 0.0]}))
-            .await
-            .unwrap();
-        assert!(!result.success);
-        assert!(result.error.as_ref().unwrap().contains("zero"));
-    }
-
-    #[tokio::test]
-    async fn test_multiply() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "multiply", "values": [3.0, 4.0, 5.0]}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "60");
-    }
-
-    #[tokio::test]
-    async fn test_pow() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "pow", "a": 2.0, "b": 10.0}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "1024");
-    }
-
-    #[tokio::test]
-    async fn test_sqrt() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "sqrt", "x": 144.0}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "12");
-    }
-
-    #[tokio::test]
-    async fn test_sqrt_negative() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "sqrt", "x": -4.0}))
-            .await
-            .unwrap();
-        assert!(!result.success);
-    }
-
-    #[tokio::test]
-    async fn test_abs() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "abs", "x": -42.5}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "42.5");
-    }
-
-    #[tokio::test]
-    async fn test_modulo() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "modulo", "a": 17.0, "b": 5.0}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "2");
-    }
-
     #[tokio::test]
     async fn test_round() {
         let tool = CalculatorTool::new();
@@ -603,28 +422,6 @@ mod tests {
         assert_eq!(result.output, "3");
     }
 
-    #[tokio::test]
-    async fn test_ln() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "ln", "x": 1.0}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "0");
-    }
-
-    #[tokio::test]
-    async fn test_exp() {
-        let tool = CalculatorTool::new();
-        let result = tool
-            .execute(json!({"function": "exp", "x": 0.0}))
-            .await
-            .unwrap();
-        assert!(result.success);
-        assert_eq!(result.output, "1");
-    }
-
     #[tokio::test]
     async fn test_factorial() {
         let tool = CalculatorTool::new();
@@ -825,4 +622,80 @@ mod tests {
         assert!(result.success);
         assert_eq!(result.output, "15");
     }
+
+    #[tokio::test]
+    async fn test_evaluate_simple() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate", "expression": "15*3+5^(2+1)"}))
+            .await
+            .unwrap();
+        assert!(result.success);
+        // 15*3 + 5^(2+1) = 45 + 5^3 = 45 + 125 = 170
+        assert_eq!(result.output, "170");
+    }
+
+    #[tokio::test]
+    async fn test_evaluate_complex() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate", "expression": "(10-2)*(3+1)"}))
+            .await
+            .unwrap();
+        assert!(result.success);
+        assert_eq!(result.output, "32");
+    }
+
+    #[tokio::test]
+    async fn test_evaluate_invalid() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate", "expression": "invalid"}))
+            .await
+            .unwrap();
+        assert!(!result.success);
+    }
+
+    #[tokio::test]
+    async fn test_evaluate_missing_expression() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate"}))
+            .await
+            .unwrap();
+        assert!(!result.success);
+    }
+
+    #[tokio::test]
+    async fn test_evaluate_with_functions() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate", "expression": "sqrt(144)"}))
+            .await
+            .unwrap();
+        assert!(result.success);
+        assert_eq!(result.output, "12");
+    }
+
+    #[tokio::test]
+    async fn test_evaluate_with_constants() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate", "expression": "pi * 2"}))
+            .await
+            .unwrap();
+        assert!(result.success);
+        assert_eq!(result.output, "6.283185307179586");
+    }
+
+    #[tokio::test]
+    async fn test_evaluate_modulo() {
+        let tool = CalculatorTool::new();
+        let result = tool
+            .execute(json!({"function": "evaluate", "expression": "17 % 5"}))
+            .await
+            .unwrap();
+        assert!(result.success);
+        assert_eq!(result.output, "2");
+    }
 }