sui-mcp-server

sui_simulate_transaction

Dry-run a Sui transaction without state changes or fees to verify success and estimate gas. Accepts BCS-encoded transaction bytes in base64.

Instructions

Dry-run a transaction. Always safe — no state changes, no fees. Returns effects, command outputs, and a suggested_gas_price. Use this before any real execution to check that the tx will succeed and to size gas. Accepts BCS-encoded transaction bytes (base64).

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": {
      "transaction_bcs_b64": "<transaction_bcs_b64>"
    },
    "name": "sui_simulate_transaction"
  }
}

Input Schema

Name	Required	Description	Default
`transaction_bcs_b64`	Yes	Base64-encoded BCS bytes of the unsigned TransactionData. The tool decodes the base64 internally.
`network`	No	Sui network. Defaults to the server's configured default.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jun 23, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Describes safety (no state changes, no fees) and outputs (effects, command outputs, gas price). Without annotations, this provides necessary behavioral context. Could specify more about input validation.

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

Conciseness5/5

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

Two well-structured sentences that front-load the purpose and safety, then detail output and usage. No unnecessary words.

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?

Given no output schema, it lists key return values. For a 2-parameter tool, it covers input format and usage context adequately. Could elaborate on output structure but sufficient.

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 coverage is 100% and both parameters are described in the schema. The description restates the base64 encoding but adds no new meaning beyond the schema.

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

Purpose5/5

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

The description clearly states it dry-runs a transaction, is safe, and has no state changes or fees. It distinguishes itself from real execution tools like sui_execute_transaction by being a simulation.

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

Usage Guidelines4/5

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

Explicitly says to use before real execution to check success and size gas. Implicitly contrasts with sui_execute_transaction, but doesn't explicitly name the sibling.

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