---
title: Program Command Block
description: "Play 0x36, client → server."
---

`play` · `0x36` · **serverbound** (client → server)

Sent when the player saves a command block GUI. `location` is the block, `command` the command text, `mode` is sequence, auto, or redstone, and `flags` holds track output, conditional, and always active. Operator-only; the server updates the block entity.

Sent by the client, read by the server. Listen for it with `client.on("ProgramCommandBlock", (data) => …)` on the receiving side.

## Fields

| Field | Type | Notes |
|---|---|---|
| `location` | Position | also `position` |
| `command` | String |  |
| `mode` | VarInt |  |
| `flags` | UByte |  |

## Send it

```ts
await client.sendPacket("ProgramCommandBlock", {
  location: /* Position */,
  command: /* String */,
  mode: /* VarInt */,
  flags: /* UByte */,
});
```

Field aliases listed under Notes are accepted as alternative keys when writing.

Source: [`src/Core/Versions/776/Packets/play/serverbound/ProgramCommandBlock.ts`](https://github.com/GDLev/mc-protocol/blob/master/src/Core/Versions/776/Packets/play/serverbound/ProgramCommandBlock.ts)