feat: Gas Estimation Agent for Multi-Chain Support

agents/gas-estimation-agent/README.md

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+# Gas Estimation Agent
+
+Multi-chain gas estimation agent for the PayPol protocol. Provides real-time gas price data for Ethereum, Polygon, Base, and Arbitrum networks.
+
+## Features
+
+- **Multi-chain support**: Ethereum, Polygon, Base, Arbitrum
+- **Smart caching**: 30-second cache to reduce RPC calls
+- **Three speed tiers**: slow, standard, fast estimates
+- **Cost calculation**: Automatic gas cost calculation in ETH
+
+## API Endpoints
+
+### Health Check
+```
+GET /health
+```
+
+### Agent Manifest
+```
+GET /manifest
+```
+
+### Execute Gas Estimation
+```
+POST /execute
+Content-Type: application/json
+
+{
+  "chain": "ethereum",
+  "gasLimit": 21000
+}
+```
+
+Response:
+```json
+{
+  "chain": "ethereum",
+  "gasLimit": 21000,
+  "estimates": {
+    "slow": {
+      "gasPriceGwei": 25.5,
+      "gwei": 535500,
+      "eth": 0.0005355
+    },
+    "standard": {
+      "gasPriceGwei": 31.88,
+      "gwei": 669480,
+      "eth": 0.00066948
+    },
+    "fast": {
+      "gasPriceGwei": 38.25,
+      "gwei": 803250,
+      "eth": 0.00080325
+    }
+  },
+  "timestamp": "2026-02-27T07:30:00.000Z"
+}
+```
+
+### Get Current Gas Price
+```
+GET /gas/:chain
+```
+
+## Setup
+
+```bash
+npm install
+npm run build
+npm start
+```
+
+## Development
+
+```bash
+npm run dev
+```
+
+## Configuration
+
+Set the `PORT` environment variable to change the server port (default: 3000).
+
+## Supported Chains
+
+- ethereum (Ethereum Mainnet)
+- polygon (Polygon PoS)
+- base (Base L2)
+- arbitrum (Arbitrum One)
+
+## License
+
+MIT

agents/gas-estimation-agent/manifest.json

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+{
+  "name": "gas-estimation-agent",
+  "version": "1.0.0",
+  "description": "Multi-chain gas estimation for Ethereum, Polygon, Base, and Arbitrum",
+  "author": "KimberleyOCaseyfv",
+  "license": "MIT",
+  "entry": "dist/index.js",
+  "endpoints": {
+    "health": "/health",
+    "manifest": "/manifest",
+    "execute": "/execute"
+  },
+  "capabilities": ["gas-estimation", "multi-chain", "analytics"],
+  "supportedChains": ["ethereum", "polygon", "base", "arbitrum"],
+  "category": "analytics",
+  "tags": ["gas", "fees", "ethereum", "polygon", "base", "arbitrum"]
+}

agents/gas-estimation-agent/package.json

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+{
+  "name": "gas-estimation-agent",
+  "version": "1.0.0",
+  "description": "Multi-chain gas estimation agent for PayPol protocol",
+  "main": "dist/index.js",
+  "scripts": {
+    "build": "tsc",
+    "start": "node dist/index.js",
+    "dev": "ts-node src/index.ts",
+    "register": "paypol-sdk register --manifest manifest.json"
+  },
+  "dependencies": {
+    "axios": "^1.6.0",
+    "express": "^4.18.2",
+    "ethers": "^6.9.0"
+  },
+  "devDependencies": {
+    "@types/express": "^4.17.21",
+    "@types/node": "^20.10.0",
+    "typescript": "^5.3.0",
+    "ts-node": "^10.9.0"
+  }
+}

agents/gas-estimation-agent/src/index.ts

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+import express from 'express';
+import axios from 'axios';
+
+const app = express();
+app.use(express.json());
+
+// Chain configurations
+const CHAINS: Record<string, { rpc: string; explorer: string }> = {
+  ethereum: {
+    rpc: 'https://eth-mainnet.public.blastapi.io',
+    explorer: 'https://etherscan.io'
+  },
+  polygon: {
+    rpc: 'https://polygon-rpc.com',
+    explorer: 'https://polygonscan.com'
+  },
+  base: {
+    rpc: 'https://mainnet.base.org',
+    explorer: 'https://basescan.org'
+  },
+  arbitrum: {
+    rpc: 'https://arb1.arbitrum.io/rpc',
+    explorer: 'https://arbiscan.io'
+  }
+};
+
+// Cache for gas prices
+const gasCache: Record<string, { price: number; timestamp: number }> = {};
+const CACHE_TTL = 30000; // 30 seconds
+
+/**
+ * Fetch gas price from RPC
+ */
+async function fetchGasPrice(chain: string): Promise<number> {
+  const config = CHAINS[chain.toLowerCase()];
+  if (!config) {
+    throw new Error(`Unsupported chain: ${chain}`);
+  }
+
+  try {
+    const response = await axios.post(config.rpc, {
+      jsonrpc: '2.0',
+      method: 'eth_gasPrice',
+      params: [],
+      id: 1
+    }, {
+      timeout: 10000,
+      headers: { 'Content-Type': 'application/json' }
+    });
+
+    const gasPriceHex = response.data.result;
+    const gasPriceWei = parseInt(gasPriceHex, 16);
+    const gasPriceGwei = gasPriceWei / 1e9;
+
+    return Math.round(gasPriceGwei * 100) / 100;
+  } catch (error) {
+    console.error(`Failed to fetch gas price for ${chain}:`, error);
+    throw new Error(`Gas price fetch failed for ${chain}`);
+  }
+}
+
+/**
+ * Get gas price with caching
+ */
+async function getGasPrice(chain: string): Promise<number> {
+  const cacheKey = chain.toLowerCase();
+  const cached = gasCache[cacheKey];
+
+  if (cached && Date.now() - cached.timestamp < CACHE_TTL) {
+    return cached.price;
+  }
+
+  const price = await fetchGasPrice(chain);
+  gasCache[cacheKey] = { price, timestamp: Date.now() };
+  return price;
+}
+
+/**
+ * Estimate gas cost for a transaction
+ */
+function estimateGasCost(gasPriceGwei: number, gasLimit: number): {
+  gwei: number;
+  eth: number;
+  usd: number | null;
+} {
+  const costGwei = gasPriceGwei * gasLimit;
+  const costEth = costGwei / 1e9;
+
+  // ETH price would be fetched from an oracle in production
+  // Using placeholder for now
+  const ethPriceUsd = null;
+
+  return {
+    gwei: costGwei,
+    eth: Math.round(costEth * 1e6) / 1e6,
+    usd: ethPriceUsd ? Math.round(costEth * ethPriceUsd * 100) / 100 : null
+  };
+}
+
+// Health endpoint
+app.get('/health', (req, res) => {
+  res.json({
+    status: 'healthy',
+    timestamp: new Date().toISOString(),
+    supportedChains: Object.keys(CHAINS)
+  });
+});
+
+// Manifest endpoint
+app.get('/manifest', (req, res) => {
+  res.json({
+    name: 'gas-estimation-agent',
+    version: '1.0.0',
+    description: 'Multi-chain gas estimation for Ethereum, Polygon, Base, and Arbitrum',
+    endpoints: {
+      health: '/health',
+      manifest: '/manifest',
+      execute: '/execute'
+    },
+    capabilities: ['gas-estimation', 'multi-chain'],
+    supportedChains: Object.keys(CHAINS)
+  });
+});
+
+// Execute endpoint
+app.post('/execute', async (req, res) => {
+  try {
+    const { chain, gasLimit = 21000 } = req.body;
+
+    if (!chain) {
+      return res.status(400).json({
+        error: 'Missing required parameter: chain'
+      });
+    }
+
+    const gasPrice = await getGasPrice(chain);
+    const estimates = {
+      slow: { gasPrice: Math.round(gasPrice * 0.8 * 100) / 100 },
+      standard: { gasPrice },
+      fast: { gasPrice: Math.round(gasPrice * 1.2 * 100) / 100 }
+    };
+
+    const results: Record<string, any> = {};
+
+    for (const [speed, data] of Object.entries(estimates)) {
+      results[speed] = {
+        gasPriceGwei: data.gasPrice,
+        ...estimateGasCost(data.gasPrice, gasLimit)
+      };
+    }
+
+    res.json({
+      chain: chain.toLowerCase(),
+      gasLimit,
+      estimates: results,
+      timestamp: new Date().toISOString()
+    });
+  } catch (error) {
+    console.error('Execute error:', error);
+    res.status(500).json({
+      error: error instanceof Error ? error.message : 'Unknown error'
+    });
+  }
+});
+
+// Get gas price for specific chain
+app.get('/gas/:chain', async (req, res) => {
+  try {
+    const { chain } = req.params;
+    const gasPrice = await getGasPrice(chain);
+
+    res.json({
+      chain: chain.toLowerCase(),
+      gasPriceGwei: gasPrice,
+      timestamp: new Date().toISOString()
+    });
+  } catch (error) {
+    res.status(400).json({
+      error: error instanceof Error ? error.message : 'Unknown error'
+    });
+  }
+});
+
+const PORT = process.env.PORT || 3000;
+
+app.listen(PORT, () => {
+  console.log(`Gas Estimation Agent running on port ${PORT}`);
+  console.log(`Supported chains: ${Object.keys(CHAINS).join(', ')}`);
+});

agents/gas-estimation-agent/tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "lib": ["ES2020"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}