session.started
A visit to a space began: a terminal opened, a process attached. The space outlives it.
Direction: Harness → Chips
Sent by: a harness
Requires a run: no
Schema: session.started.json
Fields
Section titled “Fields”Every event also carries the envelope.
| Field | Required | Type | Description |
|---|---|---|---|
v |
yes | 1 |
Protocol major version. |
type |
yes | "session.started" |
|
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. |
session_ref |
yes | string |
The harness’s own name for one visit, prefixed by the kind of harness. |
started_reason |
no | string |
Why the visit began, in the harness’s own word: startup, resume, fork. |
where |
no | string |
Where it is running, for a person to read: “mbp · ~/Work/Chips”. |
transcript_ref |
no | string |
The harness’s own transcript of this visit, so a person can jump to it. |
Example
Section titled “Example”{ "v": 1, "type": "session.started", "id": "evt_01K4ZQPX0000000000000000S1", "ts": "2026-09-04T09:12:00.000Z", "workspace_id": "ws_01K4ZQPX000000000000000001", "space_id": "spc_01K4ZQPX000000000000000002", "idempotency_key": "scout:3f9c1a-started", "actor": { "kind": "harness", "id": "hrn_01K4ZQPX000000000000000004" }, "session_ref": "scout:3f9c1a", "started_reason": "startup", "where": "mbp · ~/Work/Chips", "transcript_ref": "/Users/arjun/.scout/sessions/3f9c1a.jsonl"}