Crate agentkit_core 

Core transcript, content, usage, and cancellation primitives for agentkit.

This crate provides the foundational data model shared by every crate in the agentkit workspace. It defines:

• Transcript items (Item, ItemKind) – the messages exchanged between system, user, assistant, and tools.
• Content parts (Part, TextPart, ToolCallPart, etc.) – the multimodal pieces that make up each item.
• Streaming deltas (Delta) – incremental updates emitted while a model turn is in progress.
• Usage tracking (Usage, TokenUsage, CostUsage) – token counts and cost accounting reported by providers.
• Cancellation (CancellationController, CancellationHandle, TurnCancellation) – cooperative interruption of running turns.
• Typed identifiers (SessionId, TurnId, ToolCallId, etc.) – lightweight newtypes that prevent accidental ID mix-ups.
• Error types (NormalizeError, ProtocolError, AgentError) – shared error variants used across the workspace.

Example

use agentkit_core::{Item, ItemKind};

// Build a minimal transcript to feed into the agent loop.
let transcript = vec![
    Item::text(ItemKind::System, "You are a coding assistant."),
    Item::text(ItemKind::User, "What files are in this repo?"),
];

assert_eq!(transcript[0].kind, ItemKind::System);

Structs

ApprovalId

Identifies a pending tool-use approval request.

ArtifactId

Identifies a binary or text artifact stored externally.

CancellationController

Owner-side handle for broadcasting cancellation to running turns.

CancellationHandle

Read-only view of cancellation state, cheaply cloneable.

CostUsage

Monetary cost for a single model turn.

CustomPart

A provider-specific content part that does not fit the standard variants.

FilePart

A file attachment within an Item.

Item

A single entry in the agent transcript.

MediaPart

Binary or encoded media content (image, audio, video).

MessageId

Identifies a transcript Item.

PartId

Identifies a content part within a streaming Delta sequence.

ProviderMessageId

Provider-assigned identifier for a message.

ReasoningPart

Model reasoning or chain-of-thought output.

SessionId

Identifies an agent session.

StructuredPart

Structured JSON content, optionally paired with a JSON Schema for validation.

TaskId

Identifies a task tracked by a task manager.

TextPart

Plain text content within an Item.

TokenUsage

Token counts broken down by direction and special categories.

ToolCallId

Identifies a tool call emitted by the model.

ToolCallPart

A tool invocation request emitted by the model.

ToolResultId

Identifies a tool result.

ToolResultPart

The result of executing a tool, sent back to the model.

TurnCancellation

A snapshot of the cancellation generation at the start of a turn.

TurnId

Identifies a single turn within a session.

Usage

Token and cost usage reported by a model provider for a single turn.

Enums

AgentError

Top-level error type that unifies normalisation and protocol errors.

DataRef

A reference to content data that may live inline, at a URI, or in an artifact store.

Delta

An incremental update emitted while a model turn is streaming.

FinishReason

The reason a model turn ended.

ItemKind

The role of an Item in the transcript.

Modality

The kind of media carried by a MediaPart.

NormalizeError

Error returned when content cannot be normalised into the agentkit data model.

Part

A content part within an Item.

PartKind

Discriminant for Part variants, used in streaming Deltas.

ProtocolError

Error indicating an invalid state in the provider protocol.

ToolOutput

The payload returned by a tool execution.

Traits

ItemView

Read-only view over an Item’s essential fields.

Type Aliases

MetadataMap

A map of arbitrary key-value metadata attached to items, parts, and other structures.