# Neuron (/docs/guides/evm/precompiles/neuron)

| Property            | Value                                        |
| ------------------- | -------------------------------------------- |
| Rust implementation | `NeuronPrecompile`                           |
| Solidity interface  | `INeuron`                                    |
| Address             | `0x0000000000000000000000000000000000000804` |
| Status              | Deployed                                     |

Registers neurons, publishes serving endpoints, and submits weights. Every
function is `payable`.

## Functions [#functions]

```text
burnedRegister(uint16,bytes32)
registerLimit(uint16,bytes32,uint64)
serveAxon(uint16,uint32,uint128,uint16,uint8,uint8,uint8,uint8)
serveAxonTls(uint16,uint32,uint128,uint16,uint8,uint8,uint8,uint8,bytes)
servePrometheus(uint16,uint32,uint128,uint16,uint8)
setWeights(uint16,uint16[],uint16[],uint64)
commitWeights(uint16,bytes32)
revealWeights(uint16,uint16[],uint16[],uint16[],uint64)
```

## Added weight operations [#added-weight-operations]

| Function                           | Source extrinsic                                      |
| ---------------------------------- | ----------------------------------------------------- |
| `setMechanismWeights`              | `SubtensorModule.set_mechanism_weights`               |
| `batchSetWeights`                  | `SubtensorModule.batch_set_weights`                   |
| `commitMechanismWeights`           | `SubtensorModule.commit_mechanism_weights`            |
| `batchCommitWeights`               | `SubtensorModule.batch_commit_weights`                |
| `revealMechanismWeights`           | `SubtensorModule.reveal_mechanism_weights`            |
| `commitCrv3MechanismWeights`       | `SubtensorModule.commit_crv3_mechanism_weights`       |
| `batchRevealWeights`               | `SubtensorModule.batch_reveal_weights`                |
| `commitTimelockedWeights`          | `SubtensorModule.commit_timelocked_weights`           |
| `commitTimelockedMechanismWeights` | `SubtensorModule.commit_timelocked_mechanism_weights` |

Batch calls accept at most 16 outer items and at most 4,096 weight entries per
inner array. Timelocked commits and registration work are bounded to 5,000 and
64 bytes respectively; none of these functions accepts SCALE-encoded runtime
calls.

## Added registration and key operations [#added-registration-and-key-operations]

| Function                       | Source extrinsic                                  |
| ------------------------------ | ------------------------------------------------- |
| `register`                     | `SubtensorModule.register`                        |
| `rootRegister`                 | `SubtensorModule.root_register`                   |
| `swapHotkey`                   | `SubtensorModule.swap_hotkey`                     |
| `swapHotkeyV2`                 | `SubtensorModule.swap_hotkey_v2`                  |
| `setChildren`                  | `SubtensorModule.set_children`                    |
| `setIdentity`                  | `SubtensorModule.set_identity`                    |
| `tryAssociateHotkey`           | `SubtensorModule.try_associate_hotkey`            |
| `associateEvmKey`              | `SubtensorModule.associate_evm_key`               |
| `announceColdkeySwap`          | `SubtensorModule.announce_coldkey_swap`           |
| `executeAnnouncedColdkeySwap`  | `SubtensorModule.swap_coldkey_announced`          |
| `disputeColdkeySwap`           | `SubtensorModule.dispute_coldkey_swap`            |
| `clearColdkeySwapAnnouncement` | `SubtensorModule.clear_coldkey_swap_announcement` |

Every added operation accepts a non-Root signed origin. The precompile
dispatches the highest-level extrinsic as the mapped caller so runtime
authorization remains in force. Root-only and deprecated compatibility calls
are classified in the [coverage audit](./extrinsic-coverage).

## Typed state views [#typed-state-views]

```text
getUid(uint16,bytes32)
isNetworkMember(bytes32,uint16)
getWeights(uint16,uint16)
getBonds(uint16,uint16)
getBlockAtRegistration(uint16,uint16)
getNeuronCertificate(uint16,bytes32)
getPrometheus(uint16,bytes32)
getChainIdentity(bytes32)
getSubnetIdentity(uint16)
getLoadedEmission(uint16)
getTransactionKeyLastBlock(bytes32,uint16,uint16)
getLegacyTransactionRateBlocks(bytes32)
getWeightCommitCount(uint16,bytes32)
getWeightCommit(uint16,bytes32,uint32)
getTimelockedWeightCommitCount(uint16,uint64)
getTimelockedWeightCommit(uint16,uint64,uint32)
getLegacyTimelockedWeightCommitCount(uint8,uint16,uint64)
getLegacyTimelockedWeightCommit(uint8,uint16,uint64,uint32)
```

The indexed commit readers expose stable metadata. Timelocked ciphertext is
represented by its Keccak-256 hash and byte length instead of returning the
runtime's encrypted payload type.

## Proposed bulk runtime API [#proposed-bulk-runtime-api]

`NeuronInfoRuntimeApi.get_neurons` remains proposed. Its current result can
grow with subnet size, so no Solidity selector is assigned in this change.
Before implementation, it needs a bounded cursor-based or indexed interface
with a stable typed result. Existing single-neuron and per-field views remain
available through the deployed Neuron and Metagraph precompiles.

Source: [`neuron.sol`](https://github.com/RaoFoundation/subtensor/blob/main/precompiles/src/solidity/neuron.sol)