| name | transaction-simulator |
| description | Simulate transactions before execution to preview outcomes and detect failures. Save gas and prevent errors. |
Transaction Simulator
When to use this skill
Use this skill BEFORE executing:
- Complex swaps or trades
- Smart contract interactions
- Large transfers
- DeFi operations (stake, lend, etc.)
What It Does
Simulates your transaction on a test environment to show:
- ✅ Will it succeed or fail?
- 📊 Expected output amounts
- 💰 Actual gas costs
- ⚠️ Warnings and errors
- 🔄 State changes preview
NO REAL TRANSACTION IS SENT - It's a safe preview!
Benefits
💰 Save Money
- Avoid failed transactions (still cost gas!)
- Preview slippage before swapping
- Verify gas estimates
🛡️ Prevent Errors
- Catch insufficient balance
- Detect approval issues
- Identify smart contract bugs
📊 Better Planning
- See exact output amounts
- Preview price impact
- Understand state changes
Usage
from skills.transaction_simulator.scripts.simulate_tx import simulate_transaction
tx_data = {
'from': 'TXXXabc...',
'to': 'SunSwap_Router',
'value': 100,
'data': '...'
}
result = await simulate_transaction(tx_data)
if result['success']:
print(f"Expected output: {result['output_amount']}")
print(f"Gas cost: {result['gas_used']}")
else:
print(f"Would fail: {result['error']}")
Output Example
✅ Successful Simulation
🎮 Transaction Simulation
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Operation: Swap 100 TRX → USDT
Simulation: ✅ SUCCESS
Expected Results:
• Output: 14.85 USDT
• Price: 1 TRX = 0.1485 USDT
• Slippage: 0.5%
• Price Impact: 0.02%
Costs:
• Gas Used: ~50,000 Energy
• Est. Fee: 0.15 TRX
⏱️ Simulation Time: 1.2s
✅ Transaction will succeed
💡 Proceed with confidence!
❌ Failed Simulation
🎮 Transaction Simulation
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Operation: Swap 1000 TRX → SCAM_TOKEN
Simulation: ❌ FAILED
Error: "Transfer failed - Honeypot detected"
Details:
• Cannot sell this token after buying
• Contract has blacklist function
• Sell tax: 99%
🚨 DO NOT EXECUTE THIS TRANSACTION!
Saved you: ~1000 TRX + gas fees
Technical Details
Simulation Methods
-
TronGrid Simulation API (if available)
- Most accurate
- Uses actual blockchain state
-
Local Fork Simulation
- Creates temporary blockchain fork
- Executes transaction locally
-
Bytecode Analysis
- Analyzes contract code
- Predicts execution flow
Limitations
- ⚠️ Simulations use current blockchain state
- 🕐 Actual execution may differ if state changes
- 🔄 Time-sensitive operations may behave differently
- 📊 Gas estimates are approximate
Integration
Should auto-run before:
- Any swap >$100 USD value
- User's first interaction with a contract
- Transactions to unverified contracts
- User explicitly requests simulation
Safety
✅ 100% Safe - No real transactions sent
✅ No costs - Simulation is free
✅ Privacy - Simulations run locally when possible
