feat(tui): update system message for clarity and conciseness in tool usage instructions

apps/interfaces/tui/src/turn.rs

@@ -101,24 +101,14 @@ fn run_turn(
     let tools = all_tools();
     let defs = tool_defs(&tools);
 
-    // Build tool description list for the system prompt
-    let tool_desc: Vec<String> = tools.iter().map(|t| {
-        let params = t.parameters();
-        let required = params.get("required").and_then(|r| r.as_array())
-            .map(|a| a.iter().filter_map(|v| v.as_str()).collect::<Vec<_>>().join(", "))
-            .unwrap_or_default();
-        format!("- {}: {} (required params: {})", t.name(), t.description(), required)
-    }).collect();
-    let tool_desc_text = tool_desc.join("\n");
-
-    // Prepend system message with tool descriptions
-    let sys_msg = ChatMessage::system(format!(
-        "You are Zesdex, an AI coding agent with access to the following tools:\n\n{}\n\n\
-         When using tools, always provide ALL required parameters in your tool call. \
-         If a tool returns an error, fix the issue before retrying. \
-         Respond conversationally and helpfully.",
-        tool_desc_text
-    ));
+    // Prepend system message
+    let sys_msg = ChatMessage::system(
+        "You are Zesdex, an AI coding assistant. You have access to various tools via native function calling to help the user. \
+         For any non-trivial tasks, you MUST prioritize creating a structured plan (using `plan_enter`) and a list of TODOs (using `todowrite`) BEFORE executing any other tools or modifying files. \
+         Use other tools when necessary. If a tool returns an error, fix the issue before retrying. \
+         Respond conversationally, concisely, and helpfully."
+            .to_string(),
+    );
     messages.insert(0, sys_msg);
 
     let tool_ctx = ToolCtx::builder()