feat: dynamic swap stablecoins and default slippage selector

packages/bridge-controller/CHANGELOG.md

@@ -9,6 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Add `selectDefaultSlippagePercentage` that returns the default slippage for a chain and token combination ([#6616](https://github.com/MetaMask/core/pull/6616))
+  - Return `0.5` if requesting a bridge quote
+  - Return `undefined` (auto) if requesting a Solana swap
+  - Return `0.5` if both tokens are stablecoins (based on dynamic `stablecoins` list from LD chain config)
+  - Return `2` for all other EVM swaps
 - Add new controller metadata properties to `BridgeController` ([#6589](https://github.com/MetaMask/core/pull/6589))
 
 ### Changed

packages/bridge-controller/src/constants/bridge.ts

@@ -37,7 +37,6 @@ export const BRIDGE_QUOTE_MAX_ETA_SECONDS = 60 * 60; // 1 hour
 export const BRIDGE_QUOTE_MAX_RETURN_DIFFERENCE_PERCENTAGE = 0.5; // if a quote returns in x times less return than the best quote, ignore it
 
 export const BRIDGE_PREFERRED_GAS_ESTIMATE = 'medium';
-export const BRIDGE_DEFAULT_SLIPPAGE = 0.5;
 export const BRIDGE_MM_FEE_RATE = 0.875;
 export const REFRESH_INTERVAL_MS = 30 * 1000;
 export const DEFAULT_MAX_REFRESH_COUNT = 5;

packages/bridge-controller/src/index.ts

@@ -73,7 +73,6 @@ export {
   BRIDGE_QUOTE_MAX_ETA_SECONDS,
   BRIDGE_QUOTE_MAX_RETURN_DIFFERENCE_PERCENTAGE,
   BRIDGE_PREFERRED_GAS_ESTIMATE,
-  BRIDGE_DEFAULT_SLIPPAGE,
   BRIDGE_MM_FEE_RATE,
   REFRESH_INTERVAL_MS,
   DEFAULT_MAX_REFRESH_COUNT,
@@ -130,6 +129,7 @@ export {
 
 export {
   selectBridgeQuotes,
+  selectDefaultSlippagePercentage,
   type BridgeAppState,
   selectExchangeRateByChainIdAndAddress,
   selectIsQuoteExpired,
@@ -140,3 +140,5 @@ export {
 export { DEFAULT_FEATURE_FLAG_CONFIG } from './constants/bridge';
 
 export { getBridgeFeatureFlags } from './utils/feature-flags';
+
+export { BRIDGE_DEFAULT_SLIPPAGE } from './utils/slippage';

packages/bridge-controller/src/selectors.test.ts

@@ -11,6 +11,7 @@ import {
   selectBridgeQuotes,
   selectIsQuoteExpired,
   selectBridgeFeatureFlags,
+  selectDefaultSlippagePercentage,
 } from './selectors';
 import type { BridgeAsset, QuoteResponse } from './types';
 import { SortOrder, RequestStatus, ChainId } from './types';
@@ -1113,4 +1114,205 @@ describe('Bridge Selectors', () => {
       });
     });
   });
+
+  describe('selectDefaultSlippagePercentage', () => {
+    const mockValidBridgeConfig = {
+      minimumVersion: '0.0.0',
+      refreshRate: 3,
+      maxRefreshCount: 1,
+      support: true,
+      chains: {
+        '1': {
+          isActiveSrc: true,
+          isActiveDest: true,
+          stablecoins: ['0x123', '0x456'],
+        },
+        '10': {
+          isActiveSrc: true,
+          isActiveDest: false,
+        },
+        '1151111081099710': {
+          isActiveSrc: true,
+          isActiveDest: true,
+        },
+      },
+    };
+
+    it('should return swap default slippage when stablecoins list is not defined', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          srcChainId: '10',
+          destChainId: '10',
+        },
+      );
+
+      expect(result).toBe(2);
+    });
+
+    it('should return bridge default slippage when requesting an EVM bridge quote', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          srcChainId: '1',
+          destChainId: ChainId.SOLANA,
+        },
+      );
+
+      expect(result).toBe(0.5);
+    });
+
+    it('should return bridge default slippage when requesting a Solana bridge quote', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          destChainId: '1',
+          srcChainId: ChainId.SOLANA,
+        },
+      );
+
+      expect(result).toBe(0.5);
+    });
+
+    it('should return swap auto slippage when requesting a Solana swap quote', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          destChainId: ChainId.SOLANA,
+          srcChainId: ChainId.SOLANA,
+        },
+      );
+
+      expect(result).toBeUndefined();
+    });
+
+    it('should return swap default slippage when dest token is not a stablecoin', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x789',
+          destChainId: '1',
+          srcChainId: '1',
+        },
+      );
+
+      expect(result).toBe(2);
+    });
+
+    it('should return swap default slippage when src token is not a stablecoin', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x789',
+          destTokenAddress: '0x456',
+          destChainId: '1',
+          srcChainId: '1',
+        },
+      );
+
+      expect(result).toBe(2);
+    });
+
+    it('should return swap stablecoin slippage when both tokens are stablecoins', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          destChainId: '1',
+          srcChainId: '1',
+        },
+      );
+
+      expect(result).toBe(0.5);
+    });
+
+    it('should return bridge default slippage when srcChainId is undefined', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          destChainId: '1',
+        },
+      );
+
+      expect(result).toBe(0.5);
+    });
+
+    it('should return swap stablecoin slippage when destChainId is undefined', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x123',
+          destTokenAddress: '0x456',
+          srcChainId: '1',
+        },
+      );
+
+      expect(result).toBe(0.5);
+    });
+
+    it('should return swap default slippage when destChainId is undefined', () => {
+      const result = selectDefaultSlippagePercentage(
+        {
+          remoteFeatureFlags: {
+            bridgeConfig: mockValidBridgeConfig,
+          },
+        } as never,
+        {
+          srcTokenAddress: '0x789',
+          destTokenAddress: '0x456',
+          srcChainId: '1',
+        },
+      );
+
+      expect(result).toBe(2);
+    });
+  });
 });

packages/bridge-controller/src/selectors.ts

@@ -47,6 +47,7 @@ import {
   calcTotalEstimatedNetworkFee,
   calcTotalMaxNetworkFee,
 } from './utils/quote';
+import { getDefaultSlippagePercentage } from './utils/slippage';
 
 /**
  * The controller states that provide exchange rates
@@ -446,3 +447,39 @@ export const selectMinimumBalanceForRentExemptionInSOL = (
   new BigNumber(state.minimumBalanceForRentExemptionInLamports ?? 0)
     .div(10 ** 9)
     .toString();
+
+export const selectDefaultSlippagePercentage = createBridgeSelector(
+  [
+    (state) => selectBridgeFeatureFlags(state).chains,
+    (_, slippageParams: Parameters<typeof getDefaultSlippagePercentage>[0]) =>
+      slippageParams.srcTokenAddress,
+    (_, slippageParams: Parameters<typeof getDefaultSlippagePercentage>[0]) =>
+      slippageParams.destTokenAddress,
+    (_, slippageParams: Parameters<typeof getDefaultSlippagePercentage>[0]) =>
+      slippageParams.srcChainId
+        ? formatChainIdToCaip(slippageParams.srcChainId)
+        : undefined,
+    (_, slippageParams: Parameters<typeof getDefaultSlippagePercentage>[0]) =>
+      slippageParams.destChainId
+        ? formatChainIdToCaip(slippageParams.destChainId)
+        : undefined,
+  ],
+  (
+    featureFlagsByChain,
+    srcTokenAddress,
+    destTokenAddress,
+    srcChainId,
+    destChainId,
+  ) => {
+    return getDefaultSlippagePercentage(
+      {
+        srcTokenAddress,
+        destTokenAddress,
+        srcChainId,
+        destChainId,
+      },
+      srcChainId ? featureFlagsByChain[srcChainId]?.stablecoins : undefined,
+      destChainId ? featureFlagsByChain[destChainId]?.stablecoins : undefined,
+    );
+  },
+);

packages/bridge-controller/src/utils/metrics/properties.ts

@@ -98,6 +98,12 @@ export const isHardwareWallet = (
   return selectedAccount?.metadata?.keyring.type?.includes('Hardware') ?? false;
 };
 
+/**
+ * @param slippage - The slippage percentage
+ * @returns Whether the default slippage was overridden by the user
+ *
+ * @deprecated This function should not be used. Use {@link selectDefaultSlippagePercentage} instead.
+ */
 export const isCustomSlippage = (slippage: GenericQuoteRequest['slippage']) => {
   return slippage !== DEFAULT_BRIDGE_CONTROLLER_STATE.quoteRequest.slippage;
 };

packages/bridge-controller/src/utils/slippage.ts

@@ -0,0 +1,66 @@
+import { isCrossChain, isSolanaChainId } from './bridge';
+import type { GenericQuoteRequest } from '../types';
+
+export const BRIDGE_DEFAULT_SLIPPAGE = 0.5;
+const SWAP_SOLANA_SLIPPAGE = undefined;
+const SWAP_EVM_STABLECOIN_SLIPPAGE = 0.5;
+const SWAP_EVM_DEFAULT_SLIPPAGE = 2;
+
+/**
+ * Calculates the appropriate slippage based on the transaction context
+ *
+ * Rules:
+ * - Bridge (cross-chain): Always 0.5%
+ * - Swap on Solana: Always undefined (AUTO mode)
+ * - Swap on EVM stablecoin pairs (same chain only): 0.5%
+ * - Swap on EVM other pairs: 2%
+ *
+ * @param options - the options for the destination chain
+ * @param options.srcTokenAddress - the source token address
+ * @param options.destTokenAddress - the destination token address
+ * @param options.srcChainId - the source chain id
+ * @param options.destChainId - the destination chain id
+ * @param srcStablecoins - the list of stablecoins on the source chain
+ * @param destStablecoins - the list of stablecoins on the destination chain
+
+ * @returns the default slippage percentage for the chain and token pair
+ */
+export const getDefaultSlippagePercentage = (
+  {
+    srcTokenAddress,
+    destTokenAddress,
+    srcChainId,
+    destChainId,
+  }: Partial<
+    Pick<
+      GenericQuoteRequest,
+      'srcTokenAddress' | 'destTokenAddress' | 'srcChainId' | 'destChainId'
+    >
+  >,
+  srcStablecoins?: string[],
+  destStablecoins?: string[],
+) => {
+  if (!srcChainId || isCrossChain(srcChainId, destChainId)) {
+    return BRIDGE_DEFAULT_SLIPPAGE;
+  }
+
+  if (isSolanaChainId(srcChainId)) {
+    return SWAP_SOLANA_SLIPPAGE;
+  }
+
+  if (
+    srcTokenAddress &&
+    destTokenAddress &&
+    srcStablecoins
+      ?.map((stablecoin) => stablecoin.toLowerCase())
+      .includes(srcTokenAddress.toLowerCase()) &&
+    // If destChainId is undefined, treat req as a swap and fallback to srcStablecoins
+    (destStablecoins ?? srcStablecoins)
+      ?.map((stablecoin) => stablecoin.toLowerCase())
+      .includes(destTokenAddress.toLowerCase())
+  ) {
+    return SWAP_EVM_STABLECOIN_SLIPPAGE;
+  }
+
+  return SWAP_EVM_DEFAULT_SLIPPAGE;
+};

packages/bridge-controller/src/utils/validators.ts

@@ -85,6 +85,7 @@ export const ChainConfigurationSchema = type({
   isActiveDest: boolean(),
   refreshRate: optional(number()),
   topAssets: optional(array(string())),
+  stablecoins: optional(array(string())),
   isUnifiedUIEnabled: optional(boolean()),
   isSingleSwapBridgeButtonEnabled: optional(boolean()),
   isGaslessSwapEnabled: optional(boolean()),