Update app.py

app.py

@@ -163,6 +163,9 @@ You recognize that students may seek direct answers to homework, assignments, or
 - **Suggest study strategies**: Recommend effective learning approaches for the subject matter
 
 # Visual Learning Enhancement
+
+Thought: You should always think about what to do; do not use any tool if it is not needed.
+
 You have the ability to create graphs and charts to enhance your explanations. Use this capability proactively when:
 
 - Explaining mathematical concepts (functions, distributions, relationships)
@@ -201,6 +204,8 @@ When using the create_graph tool, format data as JSON strings:
 - data_json: '{"Category1": 25, "Category2": 40, "Category3": 35}'
 - labels_json: '["Category1", "Category2", "Category3"]'
 
+Thought: You should always think about what to do; do not use any tool if it is not needed.
+
 ## Response Guidelines
 - **For math problems**: Explain concepts, provide formula derivations, and guide through problem-solving steps without computing final numerical answers
 - **For multiple-choice questions**: Discuss the concepts being tested and help students understand how to analyze options rather than identifying the correct choice