mcp-animal-of-the-day

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

The annotations already declare readOnlyHint=true and openWorldHint=false, indicating this is a safe read operation with deterministic output. The description adds useful context about what the tool returns (facts and audio) and its daily nature, but doesn't provide additional behavioral details like rate limits or error conditions.

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 concise with two sentences that each serve distinct purposes: the first explains what the tool does, the second provides usage guidelines. Every word earns its place with zero redundancy or unnecessary elaboration.

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 parameterless read-only tool with good annotations, the description provides sufficient context about what data is returned (facts and audio) and when to use it. The main gap is the lack of output schema, but the description compensates reasonably well by specifying the return content types.

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 parameters and 100% schema description coverage, the schema fully documents the parameterless nature of this tool. The description appropriately doesn't need to explain parameters, and the baseline for this situation is 4 since there are no parameters to document.

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 specific action ('Get today's animal with facts and audio') and resource ('animal of the day'), distinguishing it from potential alternatives by specifying the daily nature of the data. It explicitly identifies the tool's purpose beyond just restating the name.

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 explicit guidance on when to use this tool: 'any time user asks to know what is the animal of the day' and 'if user asks for random facts about animals.' It clearly defines the appropriate contexts for invocation without any ambiguity.

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