# announce-coldkey-swap (/docs/tx/announce-coldkey-swap)

Step one of the two-step coldkey migration: publishes only the BlakeTwo256
hash of `new_coldkey_ss58` — committing to the new key without revealing
it — and starts the chain's announcement delay. After the delay, run the
`swap_coldkey_announced` intent to move EVERYTHING this coldkey owns
(balance, stake, subnets) to the new key; check timing with the
`coldkey_swap_announcement` read. The first announcement charges the
key-swap cost (0.1 TAO, recycled); re-announcing after the chain's
reannouncement delay is free. While an announcement is pending, the chain
blocks every other signed extrinsic from this coldkey — only the
swap-related calls and shielded (encrypted) submission go through — so the
account is operationally locked for the full delay. Before announcing, be
certain you control the new coldkey and have its mnemonic backed up. A
pending announcement can be cancelled with
`clear_coldkey_swap_announcement`, and the legitimate holder can freeze
an unauthorized one with `dispute_coldkey_swap`.

| Signer    | Origin                                 | Pallet          | Wraps                                                                                                   |
| --------- | -------------------------------------- | --------------- | ------------------------------------------------------------------------------------------------------- |
| `coldkey` | signed account (pallet role may apply) | SubtensorModule | [`SubtensorModule.announce_coldkey_swap`](/code/pallets/subtensor/src/macros/dispatches.rs#L1985-L2013) |

## Parameters [#parameters]

| Parameter          | Type   | Required | Description                                                                                                      |
| ------------------ | ------ | -------- | ---------------------------------------------------------------------------------------------------------------- |
| `new_coldkey_ss58` | string | yes      | Coldkey that will take over everything this coldkey owns once the swap executes; only its hash is published now. |

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 announce-coldkey-swap \
  --new-coldkey <ss58|name> --dry-run
btcli tx announce-coldkey-swap \
  --new-coldkey <ss58|name> -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.AnnounceColdkeySwap(new_coldkey_ss58="5F...")

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("announce_coldkey_swap", {...}, wallet)
```

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

`SubtensorModule.announce_coldkey_swap` — [`pallets/subtensor/src/macros/dispatches.rs#L1987`](/code/pallets/subtensor/src/macros/dispatches.rs#L1985-L2013):

```rust
#[pallet::call_index(125)]
#[pallet::weight(<T as crate::pallet::Config>::WeightInfo::announce_coldkey_swap())]
pub fn announce_coldkey_swap(
    origin: OriginFor<T>,
    new_coldkey_hash: T::Hash,
) -> DispatchResult {
    let who = ensure_signed(origin)?;
    let now = <frame_system::Pallet<T>>::block_number();

    if let Some((when, _)) = ColdkeySwapAnnouncements::<T>::get(who.clone()) {
        let reannouncement_delay = ColdkeySwapReannouncementDelay::<T>::get();
        let min_when = when.saturating_add(reannouncement_delay);
        ensure!(now >= min_when, Error::<T>::ColdkeySwapReannouncedTooEarly);
    } else {
        // Only charge the swap cost on the first announcement
        let swap_cost = Self::get_key_swap_cost();
        Self::charge_swap_cost(&who, swap_cost)?;
    }

    let delay = ColdkeySwapAnnouncementDelay::<T>::get();
    let when = now.saturating_add(delay);
    ColdkeySwapAnnouncements::<T>::insert(who.clone(), (when, new_coldkey_hash.clone()));

    Self::deposit_event(Event::ColdkeySwapAnnounced {
        who,
        new_coldkey_hash,
    });
    Ok(())
}
```

Delegates to [`get_key_swap_cost`](/code/pallets/subtensor/src/utils/misc.rs#L827), [`charge_swap_cost`](/code/pallets/subtensor/src/swap/swap_coldkey.rs#L68).

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