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.

Timestamp

A wall-clock instant carried on items, expressed as milliseconds since the Unix epoch in UTC. Stamped by the loop when items land in the transcript so consumers can sort, filter, or expire by age without depending on a particular date-time crate.

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.

Type Aliases

MetadataMap

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