cocos_add_loading_spinner

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

With no annotations provided, the description carries the full burden. It effectively describes the tool's behavior: it creates a centered spinner with rotation animation, explains the rotation period meaning, and specifies the return value structure. It doesn't mention side effects, permissions, or rate limits, but provides substantial behavioral context for a UI creation tool.

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 perfectly structured: first sentence states the core purpose, subsequent sentences explain key parameters, then provides a practical tip, and ends with return values. Every sentence adds value with zero waste, making it easy to scan and understand.

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?

For a 6-parameter tool with no annotations and no output schema, the description provides excellent context about parameters, behavior, and return values. The main gap is lack of explicit error conditions or prerequisites, but it covers the essential usage scenario thoroughly.

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?

With 0% schema description coverage for 6 parameters, the description compensates excellently. It explains sprite_frame_uuid's purpose (for rotation animation vs None for text-only), clarifies rotation_period meaning (full 360° revolution time), provides default context for text ('Loading...'), and gives practical guidance on generating the sprite asset.

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 tool's purpose: it adds a centered rotating icon with optional caption (loading spinner). It distinguishes from siblings by specifying this is specifically for loading indicators, unlike general UI components like buttons or labels in the sibling list.

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 this tool (for loading indicators) and includes a helpful tip on how to generate the required sprite asset. However, it doesn't explicitly state when NOT to use it or name specific alternatives among the many sibling tools.

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