AgentWallet MCP Server

simulate_transaction

Dry-run an EVM transaction without signing to validate policy and fee caps, balance coverage, and revert risk before submission.

Instructions

Dry-run an EVM transaction with nothing signed: the local guards (native cap, token cap, fee cap), the spend policy, the node's gas estimate (which fails when the call would revert), the worst-case fee, whether the balance covers it, and the call's return data. Local mode runs the full check; hosted mode runs the policy and an eth_call.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "wallet_id": "<wallet_id>",
      "to": "<to>",
      "chain_id": "<chain_id>"
    },
    "name": "simulate_transaction"
  }
}

Input Schema

Name	Required	Description	Default
`to`	Yes	Destination address
`data`	No	Optional calldata (0x-prefixed hex)
`value`	No	Native amount in human units (e.g. "0.01" ETH)	0
`chain_id`	Yes	EVM chain ID
`wallet_id`	Yes	Wallet ID (ignored in local mode)

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv1.14.8Oct 27, 2026
- addedInput schema / properties / chain_id / maximum
```
Added value: +9007199254740991
```
- addedInput schema / properties / chain_id / minimum
```
Added value: +-9007199254740991
```
- addedInput schema / properties / wallet_id / maximum
```
Added value: +9007199254740991
```
- addedInput schema / properties / wallet_id / minimum
```
Added value: +-9007199254740991
```
Addedv1.14.2Oct 14, 2026

TDQS

A3.7/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full load and does well: it enumerates the guards checked (native/token/fee caps, spend policy), discloses the failure mode of the gas estimate on reverts, and explains that local mode runs the full check while hosted mode only runs policy plus eth_call. It stops short of stating permission/auth requirements or the shape of the returned result.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the verb and the 'nothing signed' guarantee, then a compact enumeration of checks. The long clause list is dense but every item is substantive information about what gets validated.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a five-parameter, no-annotation, no-output-schema tool, the description covers what is validated, the mode split, and what the caller learns back (gas estimate, worst-case fee, balance coverage, return data). Only the precise return structure is left unspecified.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all five parameters are already documented, including the note that wallet_id is ignored in local mode. The description adds mode-level context that explains why that is, but no per-parameter syntax or format detail beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb ('Dry-run') plus resource ('an EVM transaction') and an explicit guarantee that nothing is signed, which implicitly separates it from sign_transaction and send_transaction. It never names those siblings, so the differentiation is inferred rather than stated.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'with nothing signed' and 'Dry-run' imply this is the pre-flight check before signing or sending, but the description never states when to choose it over sign_transaction/send_transaction, nor any prerequisite conditions. Usage is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.