StellarMCP

stellar_soroban_simulate

Simulate a Soroban smart contract invocation to preview its footprint, events, and results without submitting a transaction.

Instructions

Simulate a Soroban smart contract invocation to get footprint, events, and results. Does NOT submit transaction.

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": {
      "contractId": "<contractId>",
      "method": "<method>",
      "sourceAccount": "<sourceAccount>"
    },
    "name": "stellar_soroban_simulate"
  }
}

Input Schema

Name	Required	Description
`contractId`	Yes	Soroban contract ID (C...)
`method`	Yes	Contract method name to invoke
`sourceAccount`	Yes	Source account public key (G...) to use for simulation.
`args`	No	List of arguments for the contract invocation.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.9Jun 25, 2026

TDQS

A4.2/5.0

Behavior4/5

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

With no annotations provided, the description carries the behavioral burden and does well by stating the key trait: this is a simulation only and does not submit a transaction. It also tells the agent what to expect from the call: footprint, events, and results.

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?

Single sentence with no wasted words. Purpose, outputs, and the critical non-submission behavior are all front-loaded and easy to parse.

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?

The description provides enough context for an agent to call the tool correctly: what it does, what it returns conceptually, and what it does not do. Since there is no output schema, a little more detail about result shape could help, but the core calling context is sound.

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%, with each parameter already meaningfully described in the schema. The description adds no extra parameter-level context, but it does not need to because the schema covers it.

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?

States a specific verb ('Simulate'), resource ('Soroban smart contract invocation'), and expected outputs ('footprint, events, and results'). The explicit 'Does NOT submit transaction' clearly differentiates it from sibling stellar_soroban_invoke.

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?

Clearly conveys the tool is for dry-run simulation and explicitly says it does not submit the transaction. It does not name an alternative tool outright, but the non-submission caveat gives strong guidance on when this tool is appropriate.

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