Prompt template cannot access tool_schema

[KokoDoko]

I created a tutorial chatflow to learn how the tool agent works. I connected a prompt tempate to a tool and a LLM. Without the tool it works, but with the tool I get this error:

Missing value for input variable tool_schema

I include the following variable in my prompt template: {tool_schema} . But apparently this does not get filled automatically by flowise. If I manually describe the tool, then it works:

[{{ "name": "roll_dice", "description": "Rolls a twenty-sided dice.", "parameters": {{}} }}]

What is the correct way to include tool_schemas in the prompt template?