# What Parameter Types are Available in Tool Use?

This page provides usage examples of the JSON Schema parameters that are supported in [Structured Outputs (Tools)](https://docs.cohere.com/fern/pages/v2/tool-use/tool-use-overview.mdx#structured-outputs-tools).

Note: When the `strict_tools` (experimental) is set to `True`, the outputs are guaranteed to follow the schema for the tool name, parameter name, parameter data types, and the list of required parameters.

:::accordion{title="Helper code"}
The examples on this page each provide a tool schema and a `message` (the user message). To get an output, pass those values to a Chat endpoint call, as shown in the helper code below.

```python PYTHON PYTHON
import cohere
co = cohere.ClientV2(api_key="YOUR API KEY")

res = co.chat(
    # The model name. Example: command-a-plus-05-2026
    model="MODEL_NAME",  
    # The user message. Optional - you can first add a `system_message` role
    messages=[
        {
            "role": "user",
            "content": message,
        }
    ],
    # The tool schema that you define
    tools=tools,
    # This guarantes that the output will adhere to the schema
    strict_tools=True,
    # Typically, you'll need a low temperature for more deterministic outputs
    temperature=0
)

for tc in response.message.tool_calls:
    print(f"{tc.function.name} | Parameters: {tc.function.arguments}")
```
:::

## Basic types

### String

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Gets the weather of a given location",
            "parameters": {
                "type": "object",
                "properties": {
                    "location": {
                        "type": "string",
                        "description": "The location to get weather.",
                    }
                },
                "required": ["location"],
            },
        },
    },
]

message = "What's the weather in Toronto?"
```

Example output:

```mdx wordWrap
get_weather
{
  "location": "Toronto"
}
```

### Integer

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "add_numbers",
            "description": "Adds two numbers",
            "parameters": {
                "type": "object",
                "properties": {
                    "first_number": {
                        "type": "integer",
                        "description": "The first number to add.",
                    },
                    "second_number": {
                        "type": "integer",
                        "description": "The second number to add.",
                    },
                },
                "required": ["first_number", "second_number"],
            },
        },
    }
]

message = "What is five plus two"
```

Example output:

```mdx wordWrap
add_numbers
{
  "first_number": 5,
  "second_number": 2
}
```

### Float

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "add_numbers",
            "description": "Adds two numbers",
            "parameters": {
                "type": "object",
                "properties": {
                    "first_number": {
                        "type": "number",
                        "description": "The first number to add.",
                    },
                    "second_number": {
                        "type": "number",
                        "description": "The second number to add.",
                    },
                },
                "required": ["first_number", "second_number"],
            },
        },
    }
]

message = "What is 5.3 plus 2"
```

Example output:

```mdx wordWrap
add_numbers
{
  "first_number": 5.3,
  "second_number": 2
}
```

### Boolean

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "reserve_tickets",
            "description": "Reserves a train ticket",
            "parameters": {
                "type": "object",
                "properties": {
                    "quantity": {
                        "type": "integer",
                        "description": "The quantity of tickets to reserve.",
                    },
                    "trip_protection": {
                        "type": "boolean",
                        "description": "Indicates whether to add trip protection.",
                    },
                },
                "required": ["quantity", "trip_protection"],
            },
        },
    }
]

message = "Book me 2 tickets. I don't need trip protection."
```

Example output:

```mdx wordWrap
reserve_tickets
{
  "quantity": 2,
  "trip_protection": false
}
```

## Array

### With specific types

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Gets the weather of a given location",
            "parameters": {
                "type": "object",
                "properties": {
                    "locations": {
                        "type": "array",
                        "items": {"type": "string"},
                        "description": "The locations to get weather.",
                    }
                },
                "required": ["locations"],
            },
        },
    },
]

message = "What's the weather in Toronto and New York?"
```

Example output:

```mdx wordWrap
get_weather
{
  "locations": [
    "Toronto",
    "New York"
  ]
}
```

### Without specific types

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Gets the weather of a given location",
            "parameters": {
                "type": "object",
                "properties": {
                    "locations": {
                        "type": "array",
                        "description": "The locations to get weather.",
                    }
                },
                "required": ["locations"],
            },
        },
    },
]

message = "What's the weather in Toronto and New York?"
```

Example output:

```mdx wordWrap
get_weather
{
  "locations": [
    "Toronto",
    "New York"
  ]
}
```

### Lists of lists

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "maxPoints",
            "description": "Finds the maximum number of points on a line.",
            "parameters": {
                "type": "object",
                "properties": {
                    "points": {
                        "type": "array",
                        "description": "The list of points. Points are 2 element lists [x, y].",
                        "items": {
                            "type": "array",
                            "items": {"type": "integer"},
                            "description": "A point represented by a 2 element list [x, y].",
                        },
                    }
                },
                "required": ["points"],
            },
        },
    }
]

message = "Please provide the maximum number of collinear points for this set of coordinates - [[1,1],[2,2],[3,4],[5,5]]."
```

Example output:

```mdx wordWrap
maxPoints
{
  "points": [
    [1,1],
    [2,2],
    [3,4],
    [5,5]
  ]
}
```

## Others

### Nested objects

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "search_furniture_products",
            "description": "Searches for furniture products given the user criteria.",
            "parameters": {
                "type": "object",
                "properties": {
                    "product_type": {
                        "type": "string",
                        "description": "The type of the product to search for.",
                    },
                    "features": {
                        "type": "object",
                        "properties": {
                            "material": {"type": "string"},
                            "style": {"type": "string"},
                        },
                        "required": ["style"],
                    },
                },
                "required": ["product_type"],
            },
        },
    }
]

message = "I'm looking for a dining table made of oak in Scandinavian style."
```

Example output:

```mdx wordWrap
search_furniture_products
{
  "features": {
    "material": "oak",
    "style": "Scandinavian"
  },
  "product_type": "dining table"
}
```

### Enums

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "fetch_contacts",
            "description": "Fetch a contact by type",
            "parameters": {
                "type": "object",
                "properties": {
                    "contact_type": {
                        "type": "string",
                        "description": "The type of contact to fetch.",
                        "enum": ["customer", "supplier"],
                    }
                },
                "required": ["contact_type"],
            },
        },
    }
]

message = "Give me vendor contacts."
```

Example output:

```mdx wordWrap
fetch_contacts
{
  "contact_type": "supplier"
}
```

### Const

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "get_weather",
            "description": "Gets the weather of a given location",
            "parameters": {
                "type": "object",
                "properties": {
                    "location": {
                        "type": "string",
                        "description": "The location to get weather.",
                    },
                    "country": {
                        "type": "string",
                        "description": "The country for the weather lookup",
                        "const": "Canada",
                    },
                },
                "required": ["location", "country"],
            },
        },
    },
]

message = "What's the weather in Toronto and Vancouver?"
```

Example output:

```mdx wordWrap
get_weather
{
  "country": "Canada",
  "location": "Toronto"
}
---
get_weather
{
  "country": "Canada",
  "location": "Vancouver"
}
---
```

### Pattern

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "query_product_by_sku",
            "description": "Queries products by SKU pattern",
            "parameters": {
                "type": "object",
                "properties": {
                    "sku_pattern": {
                        "type": "string",
                        "description": "Pattern to match SKUs",
                        "pattern": "[A-Z]{3}[0-9]{4}",
                    }
                },
                "required": ["sku_pattern"],
            },
        },
    }
]

message = "Check the stock level of this product - 7374 hgY"
```

Example output:

```mdx wordWrap
query_product_by_sku
{
  "sku_pattern": "HGY7374"
}
```

### Format

```python PYTHON
tools = [
    {
        "type": "function",
        "function": {
            "name": "book_hotel",
            "description": "Books a hotel room for a specific check-in date",
            "parameters": {
                "type": "object",
                "properties": {
                    "hotel_name": {
                        "type": "string",
                        "description": "Name of the hotel",
                    },
                    "check_in_date": {
                        "type": "string",
                        "description": "Check-in date for the hotel",
                        "format": "date",
                    },
                },
                "required": ["hotel_name", "check_in_date"],
            },
        },
    }
]

message = "Book a room at the Grand Hotel with check-in on Dec 2 2024"
```

Example output:

```mdx wordWrap
book_hotel
{
  "check_in_date": "2024-12-02",
  "hotel_name": "Grand Hotel"
}
```

## Related pages

- [Changelog](../changelog.md)
- [Cohere](../index.md)
- [Cohere API](./cohere-api-index.md)
- [Cohere Labs](./cohere-labs-index.md)
- [Cohere Platform](./cohere-platform-index.md)
- [Cookbooks](./cookbooks-index.md)
- [Deployment Options](./deployment-options-index.md)
- [Embeddings (Vectors, Search, Retrieval)](./embeddings-vectors-search-retrieval-index.md)
- [Get Started](./get-started-index.md)
- [Going to Production](./going-to-production-index.md)

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