> ## Documentation Index
> Fetch the complete documentation index at: https://www.agentworldprotocol.com/llms.txt
> Use this file to discover all available pages before exploring further.

# world.tick

> Advance a lockstep world. Agent → World.

<ParamField body="expected_tick" type="integer" required>The current tick as the agent knows it. A mismatch fails with `AWP_TICK_MISMATCH` and nothing advances (AWP-TIM-011).</ParamField>
<ParamField body="count" type="integer">Advances to perform, ≥ 1. Default 1.</ParamField>

```json awp:tick theme={null}
{ "jsonrpc": "2.0", "id": 9, "method": "world.tick", "params": { "expected_tick": 4211, "count": 1 } }
```

Only valid in lockstep sessions. For each advance the world sends, before starting the next, every `action.status` and `world.event` produced by the advance on the control channel, then one frame carrying the new tick on every subscribed per-tick channel (AWP-TIM-003). The result is sent after the last advance, and the agent treats the advance as complete when it holds the result and a frame with that tick on every per-tick channel:

```json awp:tick-result theme={null}
{ "tick": 4212 }
```

Staged actions (admitted since the previous advance) begin executing at the first advance (AWP-TIM-010). With `tick_authority: "barrier"` the call blocks until every bound lockstep session has called `world.tick` for the current tick; all sessions then receive the same advance (AWP-TIM-012). A call retried after a lost result carries a stale `expected_tick` and is rejected, so time never advances twice:

```json awp:error theme={null}
{ "code": 3009, "message": "AWP_TICK_MISMATCH", "data": { "retryable": false, "tick": 4212, "detail": "expected_tick 4211, current 4212" } }
```

**Errors:** 2002 (`AWP_TIME_MODEL_UNSUPPORTED` in a streaming session), 3006 (`AWP_TICK_NOT_AUTHORIZED`), 3009 (`AWP_TICK_MISMATCH`).