roblox-analytics-mcp

set_default_universe

Store a default universe ID and optional alias so later analytics calls can omit the universeId parameter. Saves locally without changing Roblox data.

Instructions

Store a default universe ID so later tool calls can omit universeId, and optionally save a short alias for it. Writes to this server's local config file; it does not change anything on Roblox.

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": {
      "universeId": "<universeId>"
    },
    "name": "set_default_universe"
  }
}

Input Schema

Name	Required	Description	Default
`alias`	No	Optional short name for this universe, usable anywhere universeId is accepted.
`universeId`	Yes	Numeric universe ID to use as the default.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 20, 2026

TDQS

A4/5.0

Behavior4/5

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

No annotations are provided, so the description carries the full burden. It discloses that the tool writes to a local config file and does not change anything on Roblox, which is a key behavioral trait. However, it does not detail overwrite behavior or return values.

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?

The description is two sentences long, front-loads the main purpose, and the second sentence adds a critical caveat. No wasted 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?

The tool is simple (2 params, no output schema) and the description covers purpose, side effects, and the alias feature. It lacks explicit mention of return values or repeated-call behavior, but for a small configuration setter this is nearly 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 description coverage is 100%, so the baseline is 3. The description adds that the alias is a short name usable wherever universeId is accepted, but this is already in the schema. The description doesn't add significant 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 a specific verb ('Store') and resource ('default universe ID'), explaining the purpose of allowing later calls to omit universeId. It also distinguishes this configuration tool from the analytics/metrics siblings.

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 description implies usage when you want to set a persistent default for subsequent calls, and the local-config write contrasts with Roblox-side changes. However, it does not explicitly state when to use it versus alternatives or when not to use it.

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