checkpoint

A milestone reached and what is next. Compaction is a checkpoint. FYI tier.

Direction: Harness → Chips
Sent by: a harness
Requires a run: yes
Schema: checkpoint.json

Fields

Every event also carries the envelope.

Field	Required	Type	Description
v	yes	1	Protocol major version.
type	yes	"checkpoint"
id	yes	string	The event’s own id. Stable across a retry of the same event.
ts	yes	string	When it happened, by Chips’ clock. Stamped on the way in; a value the sender writes is replaced.
workspace_id	yes	string	A workspace identifier: ws_ followed by a ULID.
space_id	no	string	The space, when the event belongs to one.
run_id	no	string	The run, when the event belongs to one.
seq	no	number	Assigned by the server on append, monotonic per workspace. Absent on the way in.
idempotency_key	no	string	Required on every client-originated write. Sending the same key twice is a no-op.
actor	yes	object	The participant an event is attributed to.
actor.kind	yes	"person" | "harness" | "agent" | "system"	Whether a person, a harness, one of a harness’s agents or Chips itself acted.
actor.id	yes	string	The participant id, or system for Chips.
actor.harness_id	no	string	For an agent: the harness it speaks through, whose budget and runs are the agent’s (ADR 0087). Filled in by Chips.
label	yes	string	The milestone reached.
next	no	string	What the harness will do next.
compacted	no	boolean	True when the harness just compacted its context.

Example

{
  "v": 1,
  "type": "checkpoint",
  "id": "evt_01K4ZQPX00000000000000006B",
  "ts": "2026-09-02T14:22:07.004Z",
  "workspace_id": "ws_01K4ZQPX000000000000000001",
  "space_id": "spc_01K4ZQPX000000000000000002",
  "actor": {
    "kind": "harness",
    "id": "hrn_01K4ZQPX000000000000000004"
  },
  "run_id": "run_01K4ZQPX000000000000000005",
  "label": "PO read and the CRM record checked.",
  "next": "Draft the confirmation email.",
  "compacted": false
}