Asset Claimer (XCM V4 → XCM V5)

XCMv5 introduces the AssetClaimer execution hint through SetHints, which significantly simplifies the process of recovering trapped assets when XCM execution fails.

The problem before v5

When XCM execution failed and assets became trapped:

• Governance dependency: Most trapped asset recovery requires governance proposals.
• Complex procedures: Manual intervention through referendum processes.
• Long delays: Recovery could take weeks or months through governance.
• Risk of loss: Assets could remain permanently trapped if governance didn't act.
• High barriers: Small amounts often weren't worth the governance overhead.

The V5 Solution: AssetClaimer Hint

The new AssetClaimer hint allows XCM programs to preemptively designate who can claim trapped assets:

// Set asset claimer before risky operations
XcmV5Instruction.SetHints({ 
  hints: [Enum('AssetClaimer', claimerLocation)] 
})

How it Improves the Situation

The AssetClaimer hint transforms the recovery process by allowing proactive designation of claimers, eliminating the need for governance intervention in most cases.

• Before XCM V5:

  // If this XCM fails, assets become trapped
  const riskyXcm = [
      XcmInstruction.WithdrawAsset([assets]),
      XcmInstruction.BuyExecution({ fees, weight_limit }),
      XcmInstruction.Transact({ /* risky call */ }),
      XcmInstruction.DepositAsset({ assets, beneficiary })
  ]
  
  // Recovery required governance intervention
  

• With XCM V5:

  // Proactive asset claimer setup
  const saferXcm = [
      // Anyone can now claim if execution fails
      XcmV5Instruction.SetHints({ 
          hints: [Enum('AssetClaimer', claimerLocation)] 
      }),
      XcmV5Instruction.WithdrawAsset([assets]),
      XcmV5Instruction.PayFees({ asset }),
      XcmV5Instruction.Transact({ /* risky call */ }),
      XcmV5Instruction.DepositAsset({ assets, beneficiary })
  ]
  
  // Recovery can be done immediately by the claimer
  

Key Improvements

The AssetClaimer hint addresses several critical pain points in trapped asset recovery, transforming the process from governance-dependent to user-controlled.

Feature	Before XCM V5	After XCM V5
Recovery Speed	Wait for governance process (weeks/months)	Designated claimer can act immediately
Governance Burden	Every trapped asset requires a governance proposal	Only complex cases need governance intervention
Recovery Predictability	Uncertain if governance would approve recovery	Predetermined claimer provides certainty
Accessibility	Small amounts are often not worth governance overhead	Any amount can be efficiently recovered

Best Practices

Following these best practices ensures effective use of the AssetClaimer hint and maximizes the benefits of automated asset recovery.

Set Hint Early

Always set the AssetClaimer hint before any operations that might fail, ensuring trapped assets can be recovered immediately without governance intervention.

// Set claimer hint before any risky operations
XcmV5Instruction.SetHints({ hints: [Enum('AssetClaimer', claimerLocation)] }),
// ... other instructions that might fail

Use for Cross-Chain Transfers

Particularly useful for setting local accounts on destination chains:

// In remote_xcm for cross-chain transfers
const remoteXcm = [
  XcmV5Instruction.SetHints({ 
    hints: [Enum('AssetClaimer', {
      parents: 0,
      interior: { X1: { AccountId32: { id: localAccountId } } }
    })] 
  }),
  // ... transfer instructions
]

Consider Origin Preservation

When origin preservation is available, trapped assets are automatically associated with the original origin, making claiming easier without additional hints.

Migration Impact

The introduction of the AssetClaimer hint represents a significant improvement in XCM's fault tolerance and user experience, making cross-chain operations safer and more predictable.

This change makes XCM programs more resilient and user-friendly:

• Reduced risk: Assets are less likely to be permanently lost.
• Better UX: Users can recover their own assets without waiting for governance.
• Increased adoption: Lower risk encourages more XCM usage.
• Operational efficiency: Reduces governance workload for routine recoveries.

The AssetClaimer hint represents a significant improvement in XCM's fault tolerance and user experience, making cross-chain operations safer and more predictable.

Last update: August 14, 2025
| Created: August 14, 2025