What Parameter Types are Available in Tool Use?
This page describes Cohere's tool use parameters and how to work with them.
This page provides usage examples of the JSON Schema parameters that are supported in 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.
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.
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
Section titled “Basic types”String
Section titled “String”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:
get_weather
{
"location": "Toronto"
}Integer
Section titled “Integer”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:
add_numbers
{
"first_number": 5,
"second_number": 2
}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:
add_numbers
{
"first_number": 5.3,
"second_number": 2
}Boolean
Section titled “Boolean”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:
reserve_tickets
{
"quantity": 2,
"trip_protection": false
}With specific types
Section titled “With specific types”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:
get_weather
{
"locations": [
"Toronto",
"New York"
]
}Without specific types
Section titled “Without specific types”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:
get_weather
{
"locations": [
"Toronto",
"New York"
]
}Lists of lists
Section titled “Lists of lists”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:
maxPoints
{
"points": [
[1,1],
[2,2],
[3,4],
[5,5]
]
}Others
Section titled “Others”Nested objects
Section titled “Nested objects”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:
search_furniture_products
{
"features": {
"material": "oak",
"style": "Scandinavian"
},
"product_type": "dining table"
}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:
fetch_contacts
{
"contact_type": "supplier"
}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:
get_weather
{
"country": "Canada",
"location": "Toronto"
}
---
get_weather
{
"country": "Canada",
"location": "Vancouver"
}
---Pattern
Section titled “Pattern”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:
query_product_by_sku
{
"sku_pattern": "HGY7374"
}Format
Section titled “Format”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:
book_hotel
{
"check_in_date": "2024-12-02",
"hotel_name": "Grand Hotel"
}