session.open

string

Embodiment id, or omit for an observer session.

string

required

lockstep or streaming.

Channel requests: { channel, rate_hz? }.

string[]

Requested grants. Default: all the embodiment offers.

string[]

Requested administrative operations: any of snapshot, restore, reset, tick. Default: none.

integer

Only if the world advertises capabilities.seed.

boolean

Take over a bound embodiment; requires transfer_token.

string

Minted by the current holder via session.transfer (AWP-EMB-003).

object

The language instruction conditioning the agent: { content: [ …content blocks… ] }. Only if the world advertises capabilities.task — see Task. Change it mid-session with task.update.

Result — session.ready:

awp:session-ready

{ "session_id": "sess_01", "session_token": "st_9f2a7c1e4b8d6f03", "reconnect_window_ms": 30000, "heartbeat_interval_ms": 5000,
  "granted": { "channels": [ { "channel": "grid_view", "rate_hz": null, "channel_id": 1 } ],
               "action_types": ["move"], "admin": ["tick"], "envelopes": [] },
  "stream_endpoints": [ { "binding": "inline" } ],
  "frame_tree": { "frames": [ { "id": "world", "parent": null } ] },
  "clock_anchor": "2026-08-22T18:00:00Z",
  "tick": 0 }

session_id names the session everywhere it is referred to and is not a credential (AWP-SES-009); granted enumerates exactly what was granted (AWP-NEG-001); heartbeat_interval_ms sets the liveness clock (AWP-SAF-001); tick is present in lockstep sessions and is followed immediately by one frame per subscribed per-tick channel (AWP-TIM-009). The session_token is a credential: never log it unredacted (AWP-AUD-006). Errors: 2001, 2002, 2004 (AWP_SESSION_EXISTS: this connection already carries a session), 4001.

Overview

Control channel (JSON-RPC)

Frames

Schemas