feat: Add support for Robinhood chain (#8)

Author: pgrzesik

README.md

@@ -25,7 +25,7 @@ curl -fsSL https://raw.githubusercontent.com/0xProject/0x-cli/main/scripts/insta
 ## Features
 
 - **4 APIs**: EVM Swap (Allowance Holder), Gasless Swap, Solana Swap, Cross-Chain
-- **21 chains**: Ethereum, Base, Arbitrum, Optimism, Polygon, BSC, Avalanche, Linea, Scroll, Blast, Mantle, Berachain, Sonic, Unichain, World Chain, Abstract, Ink, Monad, HyperEVM, Solana, Tron
+- **22 chains**: Ethereum, Base, Arbitrum, Optimism, Polygon, BSC, Avalanche, Linea, Scroll, Blast, Mantle, Berachain, Sonic, Unichain, World Chain, Abstract, Ink, Monad, HyperEVM, Robinhood Chain, Solana, Tron
 - **Agent-first**: Auto-detect non-TTY for JSON output, structured error codes, stable exit codes, inline `RESPONSE:` schemas in every `--help`
 - **Pay-per-request (no API key)**: `--pay x402-evm` or `--pay mpp` settles ~$0.01 USDC per request via the 0x agent gateway — for autonomous agents with a funded wallet
 - **Safe by default**: OS keyring for wallet secrets, transaction simulation before every execution, `--dry-run` mode, exact token approvals
@@ -485,6 +485,7 @@ Every interactive prompt has a flag equivalent:
 | 480 | worldchain | World Chain | ETH |
 | 999 | hyperevm | HyperEVM | HYPE |
 | 2741 | abstract | Abstract | ETH |
+| 4663 | robinhood | Robinhood Chain | ETH |
 | 5000 | mantle | Mantle | MNT |
 | 8453 | base | Base | ETH |
 | 42161 | arbitrum | Arbitrum | ETH |

skills/0x-trade/references/tokens.md

@@ -14,6 +14,7 @@ Run `0x chains -o json-envelope` for the live list (with explorer URLs and chain
 | 480 | worldchain | World Chain | ETH |
 | 999 | hyperevm | HyperEVM | HYPE |
 | 2741 | abstract | Abstract | ETH |
+| 4663 | robinhood | Robinhood Chain | ETH |
 | 5000 | mantle | Mantle | MNT |
 | 8453 | base | Base | ETH |
 | 42161 | arbitrum | Arbitrum | ETH |

src/chain/mod.rs

@@ -315,6 +315,19 @@ const CHAINS: &[ChainInfo] = &[
         chain_type: ChainType::Evm,
         default_rpc_url: Some("https://rpc.hyperliquid.xyz/evm"),
     },
+    ChainInfo {
+        id: ChainId::Numeric(4663),
+        name: "robinhood",
+        display_name: "Robinhood Chain",
+        native_token: "ETH",
+        explorer_url: "https://robinhoodchain.blockscout.com",
+        chain_type: ChainType::Evm,
+        // Public endpoint documented by Robinhood; rate-limited (they steer
+        // production traffic to Alchemy et al.), which matches how the other
+        // built-in defaults here are "good enough to try, configure your own
+        // for real volume".
+        default_rpc_url: Some("https://rpc.mainnet.chain.robinhood.com"),
+    },
     ChainInfo {
         id: ChainId::Solana,
         name: "solana",
@@ -502,6 +515,21 @@ mod tests {
         assert_eq!(chain.name, "base");
     }
 
+    #[test]
+    fn test_resolve_robinhood() {
+        let by_name = resolve_chain("robinhood").unwrap();
+        assert!(by_name.is_evm());
+        assert_eq!(by_name.numeric_id(), Some(4663));
+        assert_eq!(by_name.api_chain_id(), "4663");
+        // Blockscout explorer uses the standard /tx/ path.
+        assert_eq!(
+            by_name.explorer_tx_url("0xabc"),
+            "https://robinhoodchain.blockscout.com/tx/0xabc"
+        );
+        // Resolvable by numeric ID too.
+        assert_eq!(resolve_chain("4663").unwrap().name, "robinhood");
+    }
+
     #[test]
     fn test_resolve_solana() {
         let chain = resolve_chain("solana").unwrap();