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

Given that there are no annotations, the description provides crucial behavioral traits that are not in the schema: it specifies that the tool is 'FREE,' lists specific content like 'a real example of the input and of the output each one returns,' and details the cost structure.

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 sized (one sentence), highly direct, and front-loads the most critical business constraint (free usage and emergency trigger).

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?

Since this is a zero-parameter metadata retrieval tool, the description is extremely complete. It defines the scope (all 78 tools) and the depth of information provided (costs, examples, payment methods), leaving no ambiguity for the agent.

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?

Since the schema coverage is 100% (no parameters), the baseline score applies. The description supports this by explaining that the tool will provide the necessary contextual information (inputs/outputs) for all listed tools, even if they require 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 defines the tool's purpose as cataloging all available tools and providing specific metadata (input examples, output examples, cost) for each. It effectively distinguishes itself from the specific function of sibling tools.

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?

It provides an explicit critical path for usage: 'Call this first if a tool answered HTTP 402.' This guides the agent to use the catalog exactly when it is most needed—when a specific tool has failed.

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