Mantle Tx Simulator

Overview

Prepare simulation handoff packages for external backends and translate returned technical diffs into user-readable expected outcomes before signing or execution.

Workflow

1. Normalize simulation request:
   • network
   • from/to/value/data
   • optional bundle/multicall context
2. Select an external simulation backend using references/simulation-backends.md.
3. Capture pre-state:
   • relevant token balances
   • allowance values
   • nonce and gas context
4. Produce an external simulation handoff package:
   • tx payload and network
   • required pre-state context
   • requested outputs (status/gas/logs/diffs)
5. After external execution evidence is provided, collect:
   • success/revert
   • gas estimate
   • logs/events
   • state diffs
6. Convert technical result into WYSIWYS summary with references/wysiwys-template.md.
   • ALWAYS produce a WYSIWYS section, even before external simulation results arrive.
   • If no external evidence exists yet, produce a preliminary WYSIWYS based on the request parameters, clearly labeled: "PRELIMINARY — not yet verified by simulation."
   • Pre-simulation WYSIWYS must still populate what_user_gives, what_user_gets_min (mark as "pending simulation"), and plain_language_outcome.
7. If simulation evidence is missing, fails, or confidence is low, return do_not_execute.
   • Set do_not_execute_reason with a specific explanation (e.g., "No external simulation evidence provided", "Simulation reverted", "Incomplete calldata").
   • Still produce the full Simulation Report output format even when returning do_not_execute.

Guardrails

• This skill is read-only with mantle-mcp v0.2: it cannot execute transaction simulations directly.
• Never broadcast real transactions from this skill.
• Never claim a simulation has run unless external backend output is provided.
• Distinguish simulated estimate from guaranteed execution result.
• If token decimals/pricing context is incomplete, state uncertainty explicitly.
• For bundle flows, describe each step and net effect.
• If asked to run simulation via MCP tool, explain v0.2 has no tx simulation execution tool and provide external handoff instructions.
• Always output the full Simulation Report format for every response, regardless of whether simulation evidence exists, the request is incomplete, or execution is declined. Never respond with only prose — always include the structured report.

Output Format

Mantle Simulation Report
- execution_mode: external_simulator_handoff
- backend:
- environment:
- simulated_at_utc: <external timestamp if available>
- status: pending_external_simulation | success | revert | inconclusive
- simulation_artifact: <external link/id if available>

State Diff Summary
- assets_debited:
- assets_credited:
- approvals_changed:
- contract_state_changes:

Execution Estimates (simulated — not guaranteed)
- gas_estimate:
- estimated_fee_native:
- slippage_or_price_impact_note:

WYSIWYS
- plain_language_outcome:
- what_user_gives:
- what_user_gets_min:
- do_not_execute_reason: <empty if safe>
- disclaimer: Simulation results are estimates only and do not guarantee on-chain execution outcomes.

References

• references/simulation-backends.md
• references/wysiwys-template.md