Roblox MCP

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

With no annotations provided, the description carries the full behavioral disclosure burden but offers minimal insight. It lists action names but fails to disclose immediate vs deferred effects, persistence of collision settings, side effects on the physics simulation, or what 'get_groups' returns (no output schema exists to compensate).

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

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

The description is appropriately brief (single sentence/phrase) with no wasted words after the domain identifier. However, the '[PRO]' prefix is unexplained clutter, and the colon-separated structure is telegraphic to the point of omitting necessary behavioral context for a multi-modal tool.

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

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

Given the tool's complexity (5 parameters, 3 distinct modes of operation, conditional parameter requirements) and complete absence of annotations or output schema, the description is insufficient. It omits return value documentation, error handling, and the conceptual relationship between collision groups and physics objects.

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

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

Schema description coverage is 100%, establishing a baseline of 3. The description maps high-level concepts ('register', 'set collidable', 'list') to the action enum values but adds no syntax details, validation rules, or domain context beyond what the schema already provides for the 5 parameters.

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

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

The description clearly identifies the domain ('Physics collision groups') and lists the three specific operations supported ('register, set collidable between groups, list groups'), which distinguishes it from sibling 'manage_' tools like manage_animation or manage_audio. The '[PRO]' prefix is unexplained noise but doesn't obscure the clear verb+resource mapping.

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

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

No guidance provided on when to use this tool versus other physics-related tools, or prerequisites for using collision groups (e.g., requiring existing physics bodies). No mention of when to prefer register_group vs get_groups, or error conditions for non-existent groups.

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