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SNS Canisters

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Overview

• Governance Canister: Manages proposals, neurons, and voting
• Ledger Canister: ICRC-1 token ledger for the SNS token
• Root Canister: Orchestrates upgrades and canister management
• Swap Canister: Conducts decentralization swap to distribute tokens
• Index Canister: Indexes token transactions for efficient queries
• Archive Canisters: Store historical transaction data

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SNS Governance Canister

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Core Features

• Neuron management with staking and voting
• Proposal submission and voting
• Configurable governance parameters
• Voting rewards distribution
• Treasury management
• Automatic SNS upgrades

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Key Methods

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manage_neuron

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list_neurons

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list_proposals

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get_proposal

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get_nervous_system_parameters

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get_metadata

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list_nervous_system_functions

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get_metrics

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SNS Proposal Actions

• ManageNervousSystemParameters: Update governance parameters
• AddGenericNervousSystemFunction: Add custom proposal function
• RemoveGenericNervousSystemFunction: Remove custom function
• UpgradeSnsToNextVersion: Upgrade SNS canisters
• RegisterDappCanisters: Register dapp canisters
• DeregisterDappCanisters: Deregister dapp canisters
• TransferSnsTreasuryFunds: Transfer from treasury
• UpgradeSnsControlledCanister: Upgrade dapp canister
• ManageDappCanisterSettings: Update dapp settings
• MintSnsTokens: Mint new tokens
• ManageSnsMetadata: Update SNS metadata
• ManageLedgerParameters: Update ledger parameters
• Motion: Non-executable text proposal

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SNS Neuron Structure

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SNS Topics

• Governance: Governance upgrades
• SnsFrameworkManagement: SNS framework changes
• DappCanisterManagement: Dapp canister operations
• ApplicationBusinessLogic: Custom business logic
• DaoCommunitySettings: Community settings
• TreasuryAssetManagement: Treasury operations
• CriticalDappOperations: Critical dapp operations

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SNS Swap Canister

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Swap Lifecycle

1. Pending: Swap is created but not yet open
2. Open: Accepting ICP contributions
3. Committed: Swap succeeded, finalizing
4. Aborted: Swap failed, refunding participants

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Key Methods

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get_state

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get_buyer_state

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new_sale_ticket

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get_sale_parameters

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get_derived_state

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refresh_buyer_tokens

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list_direct_participants

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Swap Participation Flow

1. Call new_sale_ticket to get participation instructions
2. Transfer ICP to the specified subaccount on ICP ledger
3. Swap automatically detects the transfer
4. When swap commits, neurons are created automatically
5. Call refresh_buyer_tokens if needed to claim neurons

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SNS Root Canister

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Key Methods

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list_sns_canisters

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get_sns_canisters_summary

• Canister ID
• Status (running, stopping, stopped)
• Memory size
• Cycles balance
• Controller principals
• Module hash

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register_dapp_canisters

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set_dapp_controllers

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SNS Deployment Architecture

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Canister Roles

• Controls the Root canister
• Manages proposals and voting
• Holds treasury funds
• Executes approved proposals

• Controls Ledger, Swap, and dapp canisters
• Coordinates SNS upgrades
• Manages dapp canister registration

• Controlled by Root
• Implements ICRC-1/ICRC-2 standards
• Manages SNS token transfers

• Controlled by NNS (during swap), then Root
• Conducts decentralization sale
• Creates initial neurons

• Controlled by Root (after decentralization)
• The actual application canisters
• Upgradeable via governance proposals

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Treasury Management

• Holds SNS tokens
• Funded from swap or minting
• Controlled by governance

• Can hold ICP tokens
• For diversification or operations
• Requires manual setup

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Best Practices

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For SNS DAO Members

1. Participate in Governance: Regularly vote or set followees
2. Understand Parameters: Review nervous system parameters
3. Monitor Proposals: Check proposals before voting deadline
4. Manage Neurons: Optimize dissolve delay for voting power
5. Use Maturity: Decide whether to stake, disburse, or merge maturity

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For SNS Developers

1. Proposal Design: Design clear, atomic proposals
2. Custom Functions: Define custom proposal functions for dapp operations
3. Test Thoroughly: Test proposals in testnet before mainnet
4. Monitor Metrics: Track governance metrics and participation
5. Upgrade Planning: Follow SNS upgrade procedures carefully

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For Swap Participants

1. Verify Parameters: Check min/max ICP, token amount, duration
2. Use Tickets: Always use new_sale_ticket before transferring
3. Transfer Quickly: Complete transfer before ticket expires
4. Save Receipts: Keep block indices of ICP transfers
5. Claim Neurons: Call refresh_buyer_tokens if neurons don’t appear

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Examples

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Voting on SNS Proposal

const result = await snsGovernance.manage_neuron({
  subaccount: neuronSubaccount,
  command: [{
    RegisterVote: {
      proposal: [{ id: proposalId }],
      vote: 1 // Yes
    }
  }]
});

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Participating in SNS Swap

// Step 1: Create ticket
const ticketResult = await snsSwap.new_sale_ticket({
  amount_icp_e8s: 100_000_000n, // 1 ICP
  subaccount: []
});

if ('Err' in ticketResult) {
  throw new Error('Failed to create ticket');
}

const ticket = ticketResult.Ok;

// Step 2: Transfer ICP to swap subaccount
await icpLedger.icrc1_transfer({
  to: {
    owner: swapCanisterId,
    subaccount: [ticket.subaccount]
  },
  amount: 100_000_000n,
  memo: [ticket.memo]
});

// Step 3: Wait for swap to commit, then claim neurons
await snsSwap.refresh_buyer_tokens({
  buyer: myPrincipal.toString()
});

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Querying SNS Metrics

const metricsResult = await snsGovernance.get_metrics({
  time_window_seconds: [86400n] // Last 24 hours
});

if ('Ok' in metricsResult) {
  const metrics = metricsResult.Ok;
  console.log('Recent proposals:', metrics.num_recently_submitted_proposals);
  
  if (metrics.treasury_metrics) {
    for (const treasury of metrics.treasury_metrics) {
      console.log(`${treasury.name}: ${treasury.amount_e8s} e8s`);
    }
  }
}

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Creating SNS Proposal

const result = await snsGovernance.manage_neuron({
  subaccount: neuronSubaccount,
  command: [{
    MakeProposal: {
      url: 'https://forum.example.com/proposal-123',
      title: 'Upgrade Dapp Canister',
      summary: 'Upgrade the main dapp canister to version 2.0',
      action: [{
        UpgradeSnsControlledCanister: {
          canister_id: [dappCanisterId],
          new_canister_wasm: wasmBytes,
          canister_upgrade_arg: [encodeArgs(...)],
          mode: [1] // Upgrade
        }
      }]
    }
  }]
});

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See Also

• NNS Governance API
• ICP Ledger API
• SNS Documentation
• SNS Launch Guide