Feature/payment agent x402

[kennethkabogo]

Description

This PR adds person-to-person payment capabilities to Mallory using x402 protocol and Solana.

What's New:

• sendPayment tool: Enables natural language payments
• checkBalance tool: Check SOL and USDC balances on mainnet/devnet
• Grid wallet integration for secure, non-custodial transaction signing
• Support for multiple delivery methods: crypto wallets, M-Pesa, bank transfers
• Payment confirmation flows with fee quotes
• Infrastructure ready for fiat offramp via Bridge API

Use Cases:

1. Crypto-to-Crypto Transfer (✅ Fully Working)

   User: "Mallory, send 10 USDC to 9xQeWvG816bUx9EPjHmaT23yvVM2ZWbrrpZb9PusVFin"
   Mallory: Shows quote ($10 + $0.01 fees = $10.01)
   User: "Yes, confirm"
   Mallory: ✅ Sent! Transaction: sol1abc...

2. Crypto-to-M-Pesa (⏳ Infrastructure Ready)

   User: "Mallory, send $50 to +254712345678 via M-Pesa in Kenya"
   Mallory: Shows quote ($50 + $0.25 fees = $50.25)
   User: "Yes, confirm"
   Mallory: Executes USDC transfer → Bridge (mocked) → M-Pesa delivery

3. Crypto-to-Bank (⏳ Infrastructure Ready)

   User: "Mallory, send $100 to my friend's bank account in Nigeria"
   Mallory: Shows quote with fees
   User: "Yes, confirm"
   Mallory: Executes USDC transfer → Bridge (mocked) → Bank delivery

Technical Implementation:

• Built on existing x402 payment infrastructure
• Uses Grid's signTransaction for non-custodial signing
• Supports both Solana mainnet and devnet
• Proper SPL token transfer with ATA creation
• Error handling and balance checking
• Crypto-to-crypto: Direct USDC transfer (working)
• Crypto-to-fiat: USDC → Bridge deposit → local delivery (needs Bridge API keys)

Hackathon Submission:
Built for Solana x402 Hackathon. Makes Mallory the first AI assistant that can send real money to people using natural language - both crypto-to-crypto and crypto-to-fiat.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Release (version bump)

Release

Is this a release? No

This is a feature addition for the hackathon submission. If Dark Research team wants to include this in a future release, they can add [release: v0.X.X] when merging.

Testing

Manual Testing Performed:

Test Cases:

1. Balance Checking ✅ Working

   Command: "Mallory, check my balance"
   Result: Successfully displayed SOL and USDC balances

2. Crypto-to-Crypto Payment ✅ Working

   Command: "Send 5 USDC to [wallet address]"
   Result: Transaction executed successfully on devnet
   Verification: Transaction visible on Solscan devnet explorer

3. Payment Confirmation Flow ✅ Working

   Command: "Send 50 USDC to +254712345678 via M-Pesa"
   Result: Showed quote with fees, asked for confirmation

4. M-Pesa Payment Flow ⏳ Partially Implemented

   Command: "Yes, confirm" (after M-Pesa quote)
   Result: USDC transfer to Bridge address works
   Status: Fiat delivery mocked (needs Bridge API integration)

5. Input Validation ✅ Working

   - Phone number format validation for M-Pesa
   - Country code requirement for fiat delivery
   - Wallet address validation for crypto transfers
   - Balance sufficiency checks

6. Error Handling ✅ Working

   - Insufficient balance: Clear error message
   - Invalid recipient: Validation error
   - Wallet not connected: Connection prompt

Implementation Status:

• ✅ Crypto-to-crypto transfers: Fully working
• ⏳ Crypto-to-fiat transfers: Infrastructure ready, needs Bridge API
• ✅ Natural language interface: Complete
• ✅ Confirmation flows: Complete
• ✅ Balance checking: Complete

**Known Limitations:**
- M-Pesa/bank delivery is mocked (needs Bridge API integration)
- Exchange rates are currently static (needs real-time FX API)

**Tested Environments:**
- macOS (Apple Silicon)
- Node.js v20
- Bun runtime
- Solana devnet

## Checklist
- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] My changes generate no new warnings or errors
- [ ] I have added tests that prove my fix is effective or that my feature works
- [x] New and existing tests pass locally with my changes
- [ ] If releasing, I have verified the version number is correct and follows semantic versioning

[vercel]

@kennethkabogo is attempting to deploy a commit to the dark Team on Vercel.

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[edgarpavlovsky]

@kennethkabogo do we need x402 to send wallet->wallet? feels like just a standard token transfer. will be easier with #109 gas abstraction as well - so not sure this PR is necessary

[kennethkabogo]

yeah, I think I misunderstood the scope here. I was aiming for a crypto to fiat infrastructure (remittance), which was mocked and not production ready. #109 makes the crypto UX much better actually, so I'll close this