Checkpoint

A persisted handoff point for a harness session.

Class Diagram

---
title: Checkpoint
config:
  look: handDrawn
  theme: colorful
  class:
    hideEmptyMembersBox: true
---
classDiagram
    class Checkpoint {
        +string id
        +string sessionId
        +string turnId
        +int32 checkpointNumber
        +string title
        +string overview
        +dictionary state
        +string summary
        +dictionary metadata
        +string createdAt
        +RedactionMetadata redaction
    }
    class RedactionMetadata {
        +boolean sanitized
        +RedactedField[] fields
        +string policy
    }
    Checkpoint *-- RedactionMetadata

Yaml Example

id: chk_abc123
sessionId: sess_abc123
turnId: turn_001
checkpointNumber: 3
title: Added harness contracts
createdAt: 2026-06-09T20:00:00Z

Properties

Name	Type	Description
id	string	Stable checkpoint identifier
sessionId	string	Stable session identifier
turnId	string	Associated turn identifier, when the checkpoint was created inside a turn
checkpointNumber	int32	Monotonic checkpoint number within the session
title	string	Short checkpoint title
overview	string	Short human-readable overview
state	dictionary	Portable checkpoint state needed to resume or hand off the session
summary	string	Optional host-authored summary or handoff note
metadata	dictionary	Host-defined checkpoint metadata
createdAt	string	ISO 8601 UTC timestamp when the checkpoint was created
redaction	RedactionMetadata	Redaction state for sensitive checkpoint fields

Composed Types

The following types are composed within Checkpoint:

• RedactionMetadata