Roblox MCP

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

With no annotations, the description carries the full burden. It discloses security sandboxing and specific blocked services, which is crucial. However, it fails to clarify execution side effects (does it mutate the workspace? is it transactional?), return value structure beyond 'serialized', or timeout/memory limits expected for arbitrary code execution.

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?

Three compact sentences. Front-loaded with the core action ('Execute arbitrary Luau code'). Security constraints follow immediately without waste. Every word earns its place.

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 high complexity (arbitrary code execution) and lack of annotations/output schema, the description provides essential security context but omits operational details critical for an LLM to invoke safely: whether execution is synchronous, potential workspace mutations, error handling behavior, or the specific serialization format of results.

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?

Input schema has 100% description coverage for the single 'source' parameter, establishing a baseline of 3. The description reinforces that this is 'Luau' code and adds the specific list of blocked services, though the schema already mentions sandboxing generically.

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?

States specific action (Execute) and resource (arbitrary Luau code) in a specific context (Roblox Studio sandbox). The '[PRO]' tag and sandbox details distinguish it from generic script management tools, though it could explicitly differentiate from sibling 'batch_execute' or 'manage_scripts'.

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?

Lists blocked services (HttpService, DataStoreService, MessagingService) and inaccessible APIs (CoreGui/CorePackages), which provides negative guidance on when not to use it. However, lacks explicit positive guidance on when to prefer this over 'batch_execute' or direct instance management tools.

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