{
  "markdown": "# BridgeKitty 🐱\n\nCross-chain bridge aggregator MCP server for AI agents. One server, 5 bridge backends, best routes across EVM, Solana, and Cosmos chains.\n\nBridgeKitty gives AI agents (Claude, Cursor, GPT, or any MCP-compatible AI) the ability to find and execute cross-chain bridge transfers — with automatic route optimization, fee comparison, balance checks, and safety warnings.\n\n**Latest npm release:** `@persistenceone/bridgekitty@0.3.9`\n\n## What's New in v0.3.9\n\n- **XPRT tools extracted** — staking, rewards, and farming tools moved to the standalone `xprt-farming-toolkit` package\n- **Persistence Interop backend removed** — BridgeKitty is now a focused bridge aggregator across 5 backends (deBridge, Relay, LI.FI, Across, Squid)\n- **Slimmer surface area** — fewer tools, clearer scope for agents\n\n<details>\n<summary>What's New in v0.3.0</summary>\n\n- **`sign_and_send` parameter** — agents can now sign and broadcast transactions directly using locally-stored wallet keys\n- **Full EVM signing support** — works with all EVM backends (Across, Relay, LI.FI, Squid, deBridge) + Persistence Interop (EIP-712)\n- **Simulation fix** — ERC20 bridges now work on fresh wallets (previously blocked by premature simulation)\n- **Solana signing** — coming in next release\n\n</details>\n\n<details>\n<summary>What's New in v0.2.0</summary>\n\n- **Solana support** — bidirectional bridging EVM ↔ Solana (native SOL delivery, not wrapped)\n- **Cosmos support** — EVM → Persistence/Cosmos Hub via Squid (Axelar)\n- **Protocol fee transparency** — deBridge fixFee, operating expenses, and total cost visible in every quote\n- **Balance warnings** — warns when wallet can't cover bridge amount + protocol fees + gas\n- **XPRT staking** — stake/unstake/claim rewards directly from the MCP server\n- **Farming multiplier** — tracks your staking tier (1x → 3x → 5x) from the rewards API\n- **Quote auto-refresh** — expired quotes automatically re-fetched on execute (60s expiry)\n- **ERC-20 approvals** — always generated for token bridges (Relay + deBridge)\n- **Bridge status tracking** — on-chain fallback when provider API hasn't indexed yet\n\n</details>\n\n## Supported Bridges\n\n| Backend | Type | Chains | Strength |\n|---------|------|--------|----------|\n| **deBridge (DLN)** | Direct | EVM + Solana | Fast intent-based fills, Solana support |\n| **Relay** | Direct | EVM + Solana | No protocol fee, gas-optimized |\n| **LI.FI** | Aggregator | EVM | Widest coverage (30+ bridges, any-to-any swap) |\n| **Across** | Direct | EVM | Fastest fills (~6s), same-token bridging |\n| **Squid (Axelar)** | Aggregator | EVM + Cosmos | Only option for EVM → Cosmos routes |\n\n### Bridge Directions\n\n| Direction | Backends | Status |\n|-----------|----------|--------|\n| EVM → EVM | All 5 | ✅ Production |\n| EVM → Solana | deBridge, Relay | ✅ Production |\n| Solana → EVM | deBridge | ✅ Production |\n| EVM → Cosmos | Squid | ✅ Production |\n\n## Quick Start\n\n### npx (zero install)\n\n```bash\nnpx @persistenceone/bridgekitty\n```\n\n### Claude Code\n\nAdd to your MCP config (`~/.claude/claude_code_config.json`):\n\n```json\n{\n  \"mcpServers\": {\n    \"bridgekitty\": {\n      \"command\": \"npx\",\n      \"args\": [\"@persistenceone/bridgekitty\"]\n    }\n  }\n}\n```\n\n### Cursor IDE\n\nAdd to Cursor's MCP settings (Settings > MCP Servers):\n\n```json\n{\n  \"bridgekitty\": {\n    \"command\": \"npx\",\n    \"args\": [\"@persistenceone/bridgekitty\"]\n  }\n}\n```\n\n### Claude Desktop\n\nAdd to `claude_desktop_config.json`:\n\n```json\n{\n  \"mcpServers\": {\n    \"bridgekitty\": {\n      \"command\": \"npx\",\n      \"args\": [\"@persistenceone/bridgekitty\"]\n    }\n  }\n}\n```\n\n## Wallet Setup\n\nBridgeKitty can manage wallets for autonomous bridging. Run `wallet_setup` to create wallets for EVM, Cosmos, and Solana — or provide your own addresses in quotes.\n\nWallet config is stored in `~/.bridgekitty/.env` (or the directory you run from). Keys never leave the local machine.\n\n| Variable | Description |\n|----------|-------------|\n| `PRIVATE_KEY` | EVM private key (hex) |\n| `MNEMONIC` | BIP-39 mnemonic (derives EVM, Cosmos, Solana keys) |\n| `SOLANA_PRIVATE_KEY` | Solana private key (base58) |\n\n## Transaction Signing\n\nBy default, `bridge_execute` returns unsigned transactions for the agent or user to sign externally.\n\nSet `sign_and_send: true` to enable autonomous signing — BridgeKitty will use the wallet keys stored in `~/.bridgekitty/.env` to handle the full flow:\n\n1. **Approval** — sends ERC-20 approval transaction (if needed)\n2. **Re-build** — re-fetches the bridge transaction with updated nonce (if approval was sent)\n3. **Simulate** — runs `eth_estimateGas` pre-flight check\n4. **Sign** — signs the transaction with the local private key\n5. **Broadcast** — submits to the chain and returns the tx hash + explorer link\n\n### Optional API Keys\n\n| Variable | Description |\n|----------|-------------|\n| `LIFI_API_KEY` | LI.FI API key (higher rate limits) |\n| `DEBRIDGE_API_KEY` | deBridge API key |\n| `SQUID_INTEGRATOR_ID` | Squid integrator ID |\n\n## MCP Tools\n\n### Core Bridge Tools\n\n| Tool | Description |\n|------|-------------|\n| `bridge_get_quote` | Get competitive quotes from all backends. Shows fees, time estimates, balance warnings. |\n| `bridge_execute` | Build transaction(s) from a quote. Handles approvals, auto-refreshes expired quotes. Set `sign_and_send: true` to auto-sign and broadcast. |\n| `bridge_status` | Track bridge progress. On-chain fallback when API hasn't indexed yet. |\n| `bridge_chains` | List supported chains with provider coverage. |\n| `bridge_tokens` | Search tokens on a chain. |\n\n### Multi-hop & Discovery\n\n| Tool | Description |\n|------|-------------|\n| `bridge_quote_multi` | Multi-hop route resolution when no direct route exists. |\n| `bridgekitty_help` | Agent onboarding guide with examples and tool usage. |\n| `xprt_onboard` | Guided onboarding flow for first-time users. |\n\n### Wallet Tools\n\n| Tool | Description |\n|------|-------------|\n| `wallet_setup` | Create wallets for EVM, Cosmos, Solana from a single mnemonic. |\n| `wallet_import` | Import an existing wallet from a mnemonic or private key. |\n| `wallet_status` | Show configured wallet addresses and key source. |\n| `wallet_balance` | Check balances across all chains with USD prices (CoinGecko). |\n\n> **XPRT staking & farming** has moved to the standalone [`xprt-farming-toolkit`](https://www.npmjs.com/package/xprt-farming-toolkit) package.\n\n## Example: Bridge USDC from Base to Arbitrum\n\n### Default (unsigned transactions)\n\n```\nAgent: \"Bridge 100 USDC from Base to Arbitrum\"\n\n→ bridge_get_quote: Gets quotes from deBridge, Relay, LI.FI, Across\n→ Shows: best rate, fees, estimated time, balance check\n→ bridge_execute: Builds approval tx + bridge tx\n→ Agent signs and sends both transactions\n→ bridge_status: Tracks until destination confirmed\n```\n\n### With sign_and_send (autonomous signing)\n\n```\nAgent: \"Bridge 100 USDC from Base to Arbitrum\"\n\n→ bridge_get_quote: Gets quotes from all backends\n→ bridge_execute with sign_and_send: true\n  → Auto-signs approval tx + bridge tx using local wallet keys\n  → Returns tx hash + explorer link\n→ bridge_status: Tracks until destination confirmed\n```\n\n## Architecture\n\n```\nAgent → MCP Tools → Routing Engine → [deBridge, Relay, LI.FI, Across, Squid]\n                         ↓\n                   Quote Cache (60s) + Circuit Breaker\n                         ↓\n                   Best Quote → buildTransaction\n                         ↓\n              ┌──────────┴──────────┐\n              ↓                     ↓\n        Unsigned TX          Signed + Broadcast\n         (default)            (sign_and_send)\n```\n\n- **Routing Engine:** Parallel quotes from all backends, ranked by output amount\n- **Circuit Breaker:** Auto-skips failing backends, gradual recovery\n- **Token Registry:** 45+ verified tokens with canonical addresses per chain\n- **Gas Estimator:** Chain-aware gas cost estimation with multi-RPC failover\n- **Balance Checker:** Validates token + native balance for fees before execution\n- **Fee Transparency:** Protocol fees (deBridge fixFee, operating expenses) surfaced in every quote\n\n## Security\n\n- Exact-amount approvals only (never unlimited)\n- Transaction simulation before execution\n- Verified token registry prevents address spoofing\n- No private keys in MCP protocol — agents sign transactions externally\n- `sign_and_send` uses locally-stored keys only (never transmitted over the network)\n- Circuit breaker prevents cascading failures\n- Error messages sanitized (no key/path leakage)\n- `.env` file permission checks + overwrite protection\n\n## Known Limitations\n\n- **Solana → EVM** returns a serialized transaction for external signing (no auto-execute)\n- **Relay status tracking** may show \"unknown\" for completed cross-chain bridges\n- **Solana SPL tokens** not yet shown in `wallet_balance` (only native SOL)\n- **Cosmos → EVM** bridging not yet supported (only EVM → Cosmos)\n\n## License\n\nMIT\n",
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