Implementation:Cohere ai Cohere python ToolParameterDefinitionsValue Model

Knowledge Sources	Cohere Python SDK
Domains	SDK, Tool Use, Function Calling, Pydantic Models
Last Updated	2026-02-15 14:00 GMT

Overview

Pydantic model representing a single parameter specification within a tool's parameter definitions map.

Description

ToolParameterDefinitionsValue defines the schema for an individual parameter in a tool definition. Each instance describes one parameter via its description (optional human-readable text), type (required string specifying the Python type), and required (optional boolean indicating whether the parameter must always be present). This model extends UncheckedBaseModel and supports extra fields via Pydantic's extra="allow" configuration, ensuring forward compatibility with API changes. It is used as the value type in Dict[str, ToolParameterDefinitionsValue] mappings within legacy (V1) tool definitions.

Usage

Use ToolParameterDefinitionsValue when constructing tool parameter definitions for the legacy Cohere chat API (V1). Each key in the parameter definitions dictionary maps a parameter name to a ToolParameterDefinitionsValue instance that describes that parameter's type, description, and whether it is required. For V2 API tool definitions, use JSON Schema-based parameters on ToolV2Function instead.

Code Reference

Source Location

• Repository: Cohere Python SDK
• File: src/cohere/types/tool_parameter_definitions_value.py Lines L1-32

Signature

class ToolParameterDefinitionsValue(UncheckedBaseModel):
    description: typing.Optional[str] = pydantic.Field(default=None)
    type: str = pydantic.Field()
    required: typing.Optional[bool] = pydantic.Field(default=None)

Import

from cohere.types import ToolParameterDefinitionsValue

I/O Contract

Fields

Field	Type	Required	Default	Description
description	Optional[str]	No	None	The description of the parameter.
type	str	Yes	(none)	The type of the parameter. Must be a valid Python type.
required	Optional[bool]	No	None	Denotes whether the parameter is always present (required) or not. Defaults to not required.

Configuration

Setting	Value	Description
extra	"allow"	Permits additional fields not defined in the schema, ensuring forward compatibility.
smart_union	True	Pydantic V1 only: enables smart union type resolution.

Usage Examples

from cohere.types import ToolParameterDefinitionsValue

# Define parameter definitions for a tool
parameter_definitions = {
    "location": ToolParameterDefinitionsValue(
        description="The city and state, e.g. San Francisco, CA",
        type="str",
        required=True,
    ),
    "unit": ToolParameterDefinitionsValue(
        description="The temperature unit to use: celsius or fahrenheit",
        type="str",
        required=False,
    ),
}

Related Pages

• Implementation:Cohere_ai_Cohere_python_ToolV2_Definition -- V2 tool definition model that uses JSON Schema instead
• Implementation:Cohere_ai_Cohere_python_ToolV2Function_Model -- V2 function specification using JSON Schema parameters
• Implementation:Cohere_ai_Cohere_python_Tool_Execution_Pattern -- End-to-end tool execution pattern
• Environment:Cohere_ai_Cohere_python_Python_SDK_Runtime