Poc/sdk client isolation

[chakra-guy]

POC: SDK Client Isolation

Problem

When a dApp uses multiple MetaMask Connect SDK clients (Multichain, EVM, Solana, Wagmi), they can interfere with each other and enter weird states. This happens because:

• Multiple clients read/write to the same storage keys without coordination
• Clients don't know about each other's existence or state changes
• One client's actions (connect/disconnect) can break another client's state

Approach

This POC explores storage-level isolation using key prefixing. Each SDK type gets its own storage namespace so they don't overwrite each other's data.

What this design does:

• Generates a deterministic instanceId from dapp.name + SDK type (e.g., myapp-evm, myapp-multichain)
• Wraps storage adapters with PrefixedStoreAdapter that prefixes all keys
• Works across all platforms (web/IndexedDB, React Native/AsyncStorage, Node)
• Same dapp.name in different browser tabs shares state (multi-tab consistency)
• Different SDK types are isolated from each other

Files changed:

• PrefixedStoreAdapter - new adapter wrapper for key prefixing
• createIsolatedStorage - utility to set up prefixed storage
• sdkType option added to MultichainOptions
• EVM client passes sdkType: 'evm' to multichain core
• Browser playground gets experiments framework for testing

Key Findings

1. Extension creates one connection per website - The MetaMask browser extension does not support separate sessions per SDK client. All clients share the same session. This means storage isolation alone doesn't fully solve the problem when using the extension.

2. MWP (QR code) flow supports true isolation - Each QR scan creates an independent session. Storage prefixing works correctly here.

3. Inconsistent behavior between flows - Extension and mobile flows behave differently, which may need further investigation.

Testing

The browser playground now includes an experiments page (?experiments URL param) with dedicated test scenarios:

• Experiment 1: Single multichain client
• Experiment 2: Two multichain clients (same type, should share)
• Experiment 3: Multichain + EVM (different types, should isolate)
• Experiments 4-6: Wagmi integration scenarios (placeholders)

Next Steps

• Decide if singleton pattern is better than isolation for extension flow
• Investigate state coordination between clients
• Complete Wagmi integration experiments