Items & Events

Complete reference for all item shapes and streaming events, aligned with the OpenResponses specification.

Open Responses Compliance

Noetic's output item types are direct type aliases of the @openrouter/sdk types (e.g., ResponsesOutputMessage, ResponsesOutputItemFunctionCall). There is no hand-rolled ItemBase or conversion layer -- the SDK types provide id, type, and status fields natively.

This means:

Any Open Responses-compatible client can consume Noetic's item log directly.
Items round-trip cleanly: output items from the SDK are used as-is; framework items (InputMessageItem, FunctionCallOutputItem) follow the same shape conventions.
The type discriminant on every item matches the Open Responses type field exactly.

Content Parts

Content part types used within message and reasoning items.

OutputTextPart

Model-generated text content with optional annotations and logprobs. Type alias for ResponseOutputText from @openrouter/sdk.

type OutputTextPart = ResponseOutputText;
// { type: 'output_text'; text: string; annotations?: ...; logprobs?: ... }

RefusalPart

Model refusal content. Type alias for OpenAIResponsesRefusalContent from @openrouter/sdk.

type RefusalPart = OpenAIResponsesRefusalContent;
// { type: 'refusal'; refusal: string }

InputTextPart

User/developer input text, created by the framework (not from the SDK).

interface InputTextPart {
  readonly type: 'input_text';
  readonly text: string;
}

ReasoningTextPart

Reasoning trace content within ReasoningItem. Type alias for ReasoningTextContent from @openrouter/sdk.

type ReasoningTextPart = ReasoningTextContent;
// { type: 'reasoning_text'; text: string }

SummaryTextPart

Reasoning summary content within ReasoningItem. Type alias for ReasoningSummaryText from @openrouter/sdk.

type SummaryTextPart = ReasoningSummaryText;
// { type: 'summary_text'; text: string }

ContentPart

Union of content parts used in message items:

type ContentPart = OutputTextPart | RefusalPart | InputTextPart;

Variant	Fields	Description
`output_text`	`text: string`	Text generated by the model
`input_text`	`text: string`	Text provided by the user or system
`refusal`	`refusal: string`	Model refusal message

Output Items (from the model)

These are type aliases of the @openrouter/sdk types. The SDK provides id, type, and status fields on each item.

MessageItem

Assistant message output item. Type alias for ResponsesOutputMessage.

type MessageItem = ResponsesOutputMessage;

Field	Type	Description
`type`	`'message'`	Discriminant
`role`	`'assistant'`	Always `assistant` for output messages
`content`	`ContentPart[]`	Message content segments

FunctionCallItem

A tool/function invocation requested by the model. Type alias for ResponsesOutputItemFunctionCall.

type FunctionCallItem = ResponsesOutputItemFunctionCall;

Field	Type	Description
`type`	`'function_call'`	Discriminant
`callId`	`string`	Unique call identifier, used to match with the output
`name`	`string`	Function name
`arguments`	`string`	JSON-encoded arguments

ReasoningItem

Internal reasoning trace emitted by reasoning-capable models. Type alias for ResponsesOutputItemReasoning. Uses ReasoningTextPart and SummaryTextPart content types (not OutputTextPart).

type ReasoningItem = ResponsesOutputItemReasoning;

Field	Type	Description
`type`	`'reasoning'`	Discriminant
`content`	`ReasoningTextPart[]`	Reasoning text content (`reasoning_text` type)
`summary`	`SummaryTextPart[]`	Summary of the reasoning (`summary_text` type)
`encryptedContent`	`string`	Optional encrypted reasoning (provider-specific)

WebSearchItem

Web search call result. Type alias for ResponsesWebSearchCallOutput.

type WebSearchItem = ResponsesWebSearchCallOutput;

Field	Type	Description
`type`	`'web_search_call'`	Discriminant
`id`	`string`	Unique item identifier
`action`	`Action`	The search action: `search`, `open_page`, or `find_in_page`
`status`	`string`	Lifecycle status

FileSearchItem

File search call result. Type alias for ResponsesOutputItemFileSearchCall.

type FileSearchItem = ResponsesOutputItemFileSearchCall;

Field	Type	Description
`type`	`'file_search_call'`	Discriminant
`id`	`string`	Unique item identifier
`queries`	`string[]`	Search queries
`status`	`string`	Lifecycle status

ImageGenerationItem

Image generation call result. Type alias for ResponsesImageGenerationCall.

type ImageGenerationItem = ResponsesImageGenerationCall;

Field	Type	Description
`type`	`'image_generation_call'`	Discriminant
`id`	`string`	Unique item identifier
`result`	`string \| null`	Generated image data
`status`	`string`	Lifecycle status

ServerToolItem

Server tool output with a vendor-prefixed type (e.g., openrouter:datetime). Based on ResponsesServerToolOutput with the type field constrained to ${string}:${string} for discriminant narrowing.

type ServerToolItem = Omit<ResponsesServerToolOutput, 'type'> & {
  readonly type: `${string}:${string}`;
};

Field	Type	Description
`type`	`${string}:${string}`	Namespaced type. The prefix identifies the vendor or domain, the name identifies the item kind.

The prefix identifies the vendor or domain (e.g., openrouter, noetic, myapp) and the name identifies the specific item kind. None of the standard item types contain a colon, so the presence of : in the type string cleanly distinguishes server tool outputs from standard items.

OutputItem Union

All output item types from the model:

type OutputItem =
  | MessageItem
  | FunctionCallItem
  | ReasoningItem
  | WebSearchItem
  | FileSearchItem
  | ImageGenerationItem
  | ServerToolItem;

Framework Items (created by Noetic)

These item types are Noetic-owned interfaces for items created by the framework, not the model.

InputMessageItem

Input message created by the framework for user, system, or developer roles.

interface InputMessageItem {
  readonly id: string;
  readonly type: 'message';
  readonly role: 'user' | 'system' | 'developer';
  readonly status: 'in_progress' | 'completed' | 'incomplete' | 'failed';
  readonly content: InputTextPart[];
}

Field	Type	Description
`type`	`'message'`	Discriminant
`role`	`'user' \| 'system' \| 'developer'`	Message author. `developer` is used for framework-injected context (e.g., from memory layers), distinct from `system` (agent instructions).
`content`	`InputTextPart[]`	Input text content segments
`status`	`string`	Lifecycle status. Includes `failed` as a Noetic extension beyond the Open Responses spec.

FunctionCallOutputItem

Tool execution output created by the harness during the tool loop. This is an input-only item type in Open Responses (sent by the developer, not the model).

interface FunctionCallOutputItem {
  readonly id: string;
  readonly type: 'function_call_output';
  readonly status: 'in_progress' | 'completed' | 'incomplete' | 'failed';
  readonly callId: string;
  readonly output: string;
}

Field	Type	Description
`type`	`'function_call_output'`	Discriminant
`callId`	`string`	Matches the `callId` from the corresponding `FunctionCallItem`
`output`	`string`	JSON-encoded tool output
`status`	`string`	Lifecycle status. Includes `failed` as a Noetic extension.

Item Union

All item types that can appear in an ItemLog:

type Item = OutputItem | InputMessageItem | FunctionCallOutputItem;

Streaming Events

When using the OpenResponses streaming API, the server emits a sequence of typed events. Each event has a type field using a dot-separated hierarchy and a sequenceNumber for ordering.

Response Lifecycle (Standard)

These events bracket the entire response.

Event	Description	Key Payload
`response.created`	Response object initialized	`response`
`response.in_progress`	Generation has started	`response`
`response.completed`	Successful completion	`response`
`response.incomplete`	Truncated (e.g., max tokens)	`response`
`response.failed`	Error occurred	`response`

Output Items (Standard)

Emitted as output items are added and completed.

Event	Description	Key Payload
`response.output_item.added`	New output item started	`item`, `outputIndex`
`response.output_item.done`	Output item complete	`item`, `outputIndex`

Content Parts (Standard)

Emitted as content parts within an output item are added and completed.

Event	Description	Key Payload
`response.content_part.added`	New content part started	`part`, `outputIndex`, `contentIndex`
`response.content_part.done`	Content part complete	`part`, `outputIndex`, `contentIndex`

Text Streaming (Standard)

Delta events for streaming text output.

Event	Description	Key Payload
`response.output_text.delta`	Text chunk received	`delta`, `logprobs`
`response.output_text.done`	Text generation complete	`text`, `logprobs`
`response.output_text.annotation.added`	Annotation added to text	`annotation`

Refusal (Standard)

Delta events when the model refuses a request.

Event	Description	Key Payload
`response.refusal.delta`	Refusal chunk	`delta`
`response.refusal.done`	Refusal complete	`refusal`

Function Call Arguments (Standard)

Delta events for streaming function call arguments.

Event	Description	Key Payload
`response.function_call_arguments.delta`	Argument chunk	`delta`, `name`
`response.function_call_arguments.done`	Arguments complete	`arguments`, `name`

Reasoning (Standard)

Delta events for reasoning model output (e.g., o1, o3).

Event	Description	Key Payload
`response.reasoning.delta`	Reasoning chunk	`delta`
`response.reasoning.done`	Reasoning complete	`text`
`response.reasoning_summary_part.added`	Summary part started	`part`
`response.reasoning_summary_part.done`	Summary part complete	`part`
`response.reasoning_summary_text.delta`	Summary text chunk	`delta`
`response.reasoning_summary_text.done`	Summary text complete	`text`

Web Search Events (Built-in Extension)

Emitted when the model uses the built-in web search capability. These are officially part of the OpenResponses specification.

Event	Description
`response.web_search_call.in_progress`	Search started
`response.web_search_call.searching`	Actively searching
`response.web_search_call.completed`	Search results ready

Image Generation Events (Built-in Extension)

Emitted when the model uses the built-in image generation capability. These are officially part of the OpenResponses specification.

Event	Description
`response.image_gen_call.in_progress`	Generation started
`response.image_gen_call.generating`	Actively generating
`response.image_gen_call.partial_image`	Partial result available
`response.image_gen_call.completed`	Image ready

How Items Flow in Noetic

Noetic's adapter layer bridges the framework's Item types and the OpenResponses wire format. Here is the lifecycle of items through a single LLM call:

┌─────────────────────────────────────────────────┐
│  ItemLog                                        │
│  ┌──────────┐ ┌──────────┐ ┌──────────────────┐ │
│  │ message  │ │ fn_call  │ │ fn_call_output   │ │
│  │ (user)   │ │          │ │                  │ │
│  └──────────┘ └──────────┘ └──────────────────┘ │
└────────────────────┬────────────────────────────┘
                     │
            extractSystemInstruction()
            itemsToInput()
                     │
                     ▼
         ┌───────────────────────┐
         │  OpenRouter SDK       │
         │  callModel()          │
         └───────────┬───────────┘
                     │
            responseToNoeticItems()
            extractUsage()
                     │
                     ▼
┌─────────────────────────────────────────────────┐
│  ItemLog (updated)                              │
│  ... + ┌──────────┐ ┌──────────────────┐        │
│        │ message  │ │ function_call    │        │
│        │ (asst)   │ │ (if tools used)  │        │
│        └──────────┘ └──────────────────┘        │
└─────────────────────────────────────────────────┘

Items in → SDK input: extractSystemInstruction() pulls system messages out as the instructions parameter. itemsToInput() converts remaining Noetic Items into the OpenResponses input format.
SDK calls model: The OpenRouter SDK sends the request and handles the response.
SDK response → Items out: responseToNoeticItems() converts output items back to Noetic Items. extractUsage() pulls token counts and cost.
Items appended: New items are appended to the ItemLog. The Projector reads the full ItemLog when assembling the View for the next LLM call.

Server tool items and reasoning items are skipped during input conversion (they are internal metadata). The adapter converts all output item types (message, function_call, reasoning, web_search_call, file_search_call, image_generation_call, and server tool outputs) into their corresponding Noetic Item variants.

Framework Events

In addition to OpenResponses streaming events, Noetic emits framework-level events during execution. These events use the harness config.name as a prefix and have source: 'framework'.

Event	Description	Key Payload
`{name}:step_started`	Before each step executes	`stepId`, `kind`
`{name}:step_completed`	After each step completes	`stepId`, `kind`
`{name}:tool_round_started`	Before a tool execution round	`round`, `toolCount`
`{name}:tool_call_started`	Before each tool call	`name`, `callId`
`{name}:tool_call_completed`	After each tool call	`name`, `callId`, `error`
`{name}:tool_round_completed`	After all tool calls in a round	`round`, `toolCount`

Framework events are available through harness.execute(input).getFullStream() alongside SDK events. They can be distinguished by the source field:

for await (const event of harness.execute('Hello').getFullStream()) {
  if (event.source === 'sdk') {
    // OpenResponses SSE event
  }
  if (event.source === 'framework') {
    // Noetic lifecycle event, e.g. 'myagent:step_started'
  }
}

Context & Event Log -- the ItemLog interface and usage.
Context Types -- type definitions for all item variants.
Adapter Types -- the OpenRouter adapter and LlmProviderConfig.
AgentHarness -- how the harness orchestrates the item flow.

Items & Events

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