# pow-register (/docs/tx/pow-register)

Direct submission with zero tip pays no transaction fee, burn or initial
collateral purchase. Root is excluded. The proof binds the subnet, signing
coldkey and hotkey; reused or stale challenge blocks are rejected. A full
subnet applies ordinary pruning and immunity rules. Mine a fresh intent
with `client.mine_pow_registration` and submit it promptly.

| Signer    | Origin                                 | Pallet          | Wraps                                                                                        |
| --------- | -------------------------------------- | --------------- | -------------------------------------------------------------------------------------------- |
| `coldkey` | signed account (pallet role may apply) | SubtensorModule | [`SubtensorModule.pow_register`](/code/pallets/subtensor/src/macros/dispatches.rs#L852-L863) |

## Parameters [#parameters]

| Parameter           | Type             | Required | Description                                      |
| ------------------- | ---------------- | -------- | ------------------------------------------------ |
| `netuid`            | integer          | yes      | Non-root subnet with PoW enabled.                |
| `work_block`        | integer          | yes      | Recent block used for the challenge.             |
| `nonce`             | integer          | yes      | Unsigned 64-bit solution nonce.                  |
| `work_hex`          | string           | yes      | 32-byte registration seal, encoded as hex.       |
| `hotkey_ss58`       | string           | no       | Hotkey receiving the UID.                        |
| `mining_workers`    | integer          | no       | Workers when the CLI refreshes an expired proof. |
| `mining_timeout`    | number           | no       | Seconds allowed for CLI proof refresh.           |
| `mining_backend`    | string           | no       | auto, gpu, or cpu mining.                        |
| `mining_device_ids` | array of integer | no       | GPU device ids, or all discovered GPUs.          |

Address parameters (`--hotkey`, `--coldkey`, `--dest`, ...) accept a raw ss58
address, an address-book or proxy-book name, or a local wallet/hotkey name.

## CLI [#cli]

Preview with `--dry-run` (shows fee, effects, and policy result without
submitting), then submit:

```bash
btcli tx pow-register \
  --netuid <int> \
  --work-block <int> \
  --nonce <int> \
  --work-hex <value> --dry-run
btcli tx pow-register \
  --netuid <int> \
  --work-block <int> \
  --nonce <int> \
  --work-hex <value> -w my_coldkey
```

## Python [#python]

```python
import bittensor as bt
from bittensor.wallet import Wallet

wallet = Wallet(name="my_coldkey", hotkey="my_hotkey")
intent = bt.PowRegister(netuid=1, work_block=0, nonce=0, work_hex="...")

sub = bt.Subtensor()
plan = sub.plan(intent, wallet)   # fee, effects, policy — no submission
result = sub.execute(intent, wallet)
if not result.success:
    print(result.error.code, result.error.remediation)
```

(`bt.Subtensor` is also the async client — `async with bt.Subtensor() as client:`
— see [The client](/docs/concepts/client).) Or build the intent by op name, as
an agent would:

```python
result = sub.execute_tool("pow_register", {...}, wallet)
```

## On-chain implementation [#on-chain-implementation]

`SubtensorModule.pow_register` — [`pallets/subtensor/src/macros/dispatches.rs#L854`](/code/pallets/subtensor/src/macros/dispatches.rs#L852-L863):

```rust
#[pallet::call_index(152)]
#[pallet::weight((<T as crate::pallet::Config>::WeightInfo::pow_register(), Pays::No))]
pub fn pow_register(
    origin: OriginFor<T>,
    netuid: NetUid,
    work_block: u64,
    nonce: u64,
    work: [u8; 32],
    hotkey: T::AccountId,
) -> DispatchResult {
    Self::do_pow_register(origin, netuid, work_block, nonce, work, hotkey)
}
```

Delegates to [`do_pow_register`](/code/pallets/subtensor/src/subnets/registration.rs#L123).

Every file is browsable under [/code](/code) exactly as built into the runtime, or as plain text under `/code/raw/<path>` (index: [`/code/index.json`](/code/index.json)).