Module open_responses 

Open Responses specification conformance layer.

This module implements the Open Responses specification for vendor-neutral LLM interfaces. It provides:

• Unified item types with state machine semantics
• Semantic streaming events (not raw token deltas)
• Response objects with standardized structure
• Error handling with structured error types
• Extension points for VT Code-specific item types

The implementation bridges VT Code’s internal event system (ThreadEvent) to Open Responses-compliant structures while maintaining backwards compatibility.

Structs

CustomItem

Custom/extension item type.

DualEventEmitter

Adapter that wraps a VT Code event sink and also emits Open Responses events.

FunctionCallItem

A function call item representing a tool invocation request.

FunctionCallOutputItem

Output from a function call execution.

IncompleteDetails

Details about why a response was incomplete.

InputFileContent

File input provided to the model.

InputImageContent

Image input provided to the model.

InputTokensDetails

Detailed breakdown of input token usage.

MessageItem

A message item representing conversation content.

OpenResponseError

Structured error object for Open Responses.

OpenResponsesIntegration

Open Responses integration manager.

OpenUsage

Token usage statistics for a response.

OutputTokensDetails

Detailed breakdown of output token usage.

ReasoningItem

A reasoning item containing model’s internal thought process.

Request

The main request object per the Open Responses specification.

Response

The main response object per the Open Responses specification.

ResponseBuilder

Builder for constructing Open Responses Response objects from VT Code events.

SequencedEvent

Wrapper for streaming events with sequence number for ordering. Used when serializing events for SSE transport.

SpecificToolChoice

Specific tool choice.

VecStreamEmitter

Vector-based event emitter for collecting events.

Enums

ContentPart

Content part types supported by Open Responses.

ImageDetail

Level of detail for image analysis.

IncompleteReason

Reasons why a response may be incomplete.

ItemStatus

Lifecycle status for items in the Open Responses model.

MessageRole

Role of a message author.

OpenResponseErrorCode

Specific error codes providing additional detail.

OpenResponseErrorType

Category of error that occurred.

OutputItem

Output items generated by the model.

ResponseStatus

Status of a response.

ResponseStreamEvent

Semantic streaming events per the Open Responses specification.

ToolChoice

Tool choice options.

ToolChoiceMode

Standard tool choice modes.

Constants

VTCODE_EXTENSION_PREFIX

VT Code extension prefix for custom item types and events.

Traits

OpenResponsesProvider

Trait for types that can provide Open Responses integration.

StreamEventEmitter

Trait for emitting Open Responses streaming events.

ToOpenResponse

Extension trait for converting VT Code LLM responses to Open Responses format.

Functions

generate_item_id

Generates a unique output item ID.

generate_response_id

Generates a unique response ID.

is_valid_extension_type

Validates that a custom type follows the Open Responses extension naming convention. Custom types must be prefixed with an implementor slug (e.g., vtcode:file_change).

Type Aliases

ContentPartId

Unique identifier for a content part within an output item.

OpenResponsesCallback

Callback type for receiving Open Responses streaming events.

OutputItemId

Unique identifier for an output item.

ResponseId

Unique identifier for a response.