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Defined in ERC-7867 (Proposed)
The flowControl capability allows dapps to specify how transaction batches should behave when individual calls fail or revert. This provides fine-grained control over transaction execution flow and enables more sophisticated error handling strategies.
This capability is currently proposed in ERC-7867 and is not yet finalized. Implementation details may change as the specification develops.

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Parameters

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onFailure
string
Specifies the behavior when a transaction call fails or reverts.Possible values:
  • "continue": Continue executing remaining calls
  • "stop": Stop execution on failure
  • "retry": Attempt to retry the failed call
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fallbackCall
object
Optional fallback transaction to execute if the primary call fails.

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Returns

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flowControl
object
The flow control capability configuration for the specified chain.

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Example Usage

const capabilities = await provider.request({
  method: 'wallet_getCapabilities',
  params: [userAddress]
});

const flowControlCapability = capabilities["0x2105"]?.flowControl;

const result = await provider.request({
  method: 'wallet_sendCalls',
  params: [{
    version: "1.0",
    chainId: "0x2105",
    from: userAddress,
    calls: [
      {
        to: "0x1234567890123456789012345678901234567890",
        value: "0x0",
        data: "0xa9059cbb000000000000000000000000...",
        flowControl: {
          onFailure: "continue",
          fallbackCall: {
            to: "0x...",
            data: "0x..."
          }
        }
      }
    ]
  }]
});

{
  "0x2105": {
    "flowControl": {
      "supported": true
    }
  }
}

{
  "0x2105": {
    "flowControl": {
      "supported": false
    }
  }
}

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Error Handling

CodeMessageDescription
4100Flow control not supportedWallet does not support flow control functionality
5700Flow control capability requiredTransaction requires flow control but wallet doesn’t support it
5800Invalid flow control parametersThe provided flow control configuration is invalid

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Potential Use Cases

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E-commerce Transactions

Handle scenarios where some purchases succeed while others fail: 
// Example: Multi-item purchase with flow control
const purchaseResult = await provider.request({
  method: 'wallet_sendCalls',
  params: [{
    version: "1.0",
    chainId: "0x2105",
    from: userAddress,
    calls: [
      // Primary item purchase
      {
        to: marketplaceContract,
        value: "0x0",
        data: purchaseItem1CallData,
        flowControl: { onFailure: "continue" }
      },
      // Secondary item purchase  
      {
        to: marketplaceContract,
        value: "0x0", 
        data: purchaseItem2CallData,
        flowControl: { onFailure: "continue" }
      },
      // Payment processing (critical)
      {
        to: paymentContract,
        value: "0x16345785d8a0000",
        data: "0x",
        flowControl: { onFailure: "stop" }
      }
    ]
  }]
});

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DeFi Operations with Fallbacks

Implement sophisticated DeFi strategies with backup options: 
// Example: Swap with fallback routing
const swapWithFallback = await provider.request({
  method: 'wallet_sendCalls',
  params: [{
    version: "1.0",
    chainId: "0x2105", 
    from: userAddress,
    calls: [
      // Primary DEX swap
      {
        to: primaryDexAddress,
        value: "0x0",
        data: primarySwapCallData,
        flowControl: {
          onFailure: "fallback",
          fallbackCall: {
            to: secondaryDexAddress,
            data: secondarySwapCallData
          }
        }
      }
    ]
  }]
});

​
Batch Operations with Error Recovery

Execute batch operations that can gracefully handle individual failures: 
// Example: Bulk token approvals with recovery
const bulkApprovals = await provider.request({
  method: 'wallet_sendCalls',
  params: [{
    version: "1.0",
    chainId: "0x2105",
    from: userAddress,
    calls: tokenAddresses.map((token, index) => ({
      to: token,
      value: "0x0",
      data: approveCallData,
      flowControl: {
        onFailure: "continue", // Don't stop batch if one approval fails
        retryCount: 2 // Retry failed approvals
      }
    }))
  }]
});

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Checking Capability Support

Once implemented, check for flow control support: 
async function checkFlowControlSupport() {
  try {
    const capabilities = await provider.request({
      method: 'wallet_getCapabilities',
      params: [userAddress]
    });
    
    const flowControlCapability = capabilities["0x2105"]?.flowControl;
    
    if (flowControlCapability?.supported) {
      console.log("Flow control capability supported");
      return true;
    } else {
      console.log("Flow control capability not supported");
      return false;
    }
  } catch (error) {
    console.error("Error checking flow control capability:", error);
    return false;
  }
}

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Expected Benefits

When implemented, flow control will provide:
  1. Better User Experience: Partial success instead of complete failure
  2. Flexible Error Handling: Apps can define custom failure responses
  3. Reduced Gas Waste: Avoid re-executing successful operations
  4. Complex Workflows: Enable sophisticated multi-step processes

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Development Status

This capability is actively being developed:
  • ERC-7867: Formal proposal for flow control capability
  • Community Input: Ongoing discussions about implementation details
  • Wallet Integration: Pending finalization of specification

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Preparing for Flow Control

While waiting for implementation, developers can:
  1. Design Flexible Architecture: Build apps that can adapt to different execution models
  2. Implement Fallback Logic: Create manual fallback strategies for critical operations
  3. Monitor Specification: Track ERC-7867 progress for implementation updates
  4. Test Sequential Execution: Use current capabilities to simulate flow control behavior
Stay updated on ERC-7867 development to implement flow control as soon as it’s available in production wallets.
The examples above are conceptual and may not reflect the final implementation. Always refer to the latest ERC-7867 specification for accurate details.
Flow control works alongside other capabilities: