Upload a thumbnail to Roblox

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

With no annotations provided, the description takes on full responsibility for behavioral disclosure. It proactively explains the asynchronous moderation behavior, which is non-obvious and essential for the agent to correctly interpret results. This goes beyond a simple action statement and sets a high bar for transparency.

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 a single, compact sentence that front-loads the purpose and immediately addresses the most important behavioral nuance. Every word earns its place; there is no wasted verbiage or redundancy.

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 moderate complexity (2 params, no output schema), the description covers the essential elements: action, resource, and critical asynchronous behavior. It doesn't mention potential errors (e.g., invalid image path, size limits) but with no output schema, it could have added a note on response handling. Still, it's reasonably complete for its purpose.

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?

The input schema covers 100% of parameters with descriptions for both 'game' and 'imagePath'. The description does not add extra semantic meaning beyond the schema, but the baseline of 3 applies because the schema is self-sufficient. No additional details about format, validation, or constraints are needed.

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 states the action ('Publish a local image as a thumbnail on a Roblox game') with a specific verb and resource. It distinguishes from siblings like 'generate_thumbnail' (which generates rather than uploads) and 'delete_thumbnail' (which deletes), though it doesn't explicitly contrast with them.

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?

The description provides clear context on when to use the tool (publishing a local image) and adds critical information about asynchronous moderation, implying that a Pending result is expected. However, it doesn't explicitly state when not to use it or mention alternatives like 'upload_generation' (which might be for uploading generated images).

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