Katzilla MCP

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

Annotations already indicate read-only, non-destructive, idempotent, and open-world behavior. The description adds valuable context beyond annotations: it discloses the data source ('Agify'), update frequency ('monthly'), return format ('Katzilla envelope'), and details about quality scores and citation data. This enriches the agent's understanding without contradicting annotations.

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 efficiently structured in two sentences: the first states the core purpose and source, the second details the return format and its components. Every phrase adds value (e.g., 'Free Tier', 'updates monthly', quality/citation breakdown), with no redundant or vague language.

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 simplicity (1 parameter, 100% schema coverage, annotations provided, output schema exists), the description is complete. It covers purpose, source, behavioral context, and output structure, leaving no gaps for the agent to infer. The existence of an output schema means the description need not explain return values in detail.

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 has 100% description coverage, with the 'name' parameter clearly documented. The description does not add any additional semantic details about the parameter beyond what the schema provides (e.g., no examples, formatting rules, or constraints). Baseline 3 is appropriate since the schema fully covers the parameter.

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 explicitly states the tool's purpose: 'Predict the age of a person based on their name.' It specifies the verb ('predict'), resource ('age'), and distinguishes it from siblings by mentioning the data source 'Agify (Free Tier)' and the unique 'Katzilla envelope' return format, which no other sibling tool references.

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 for when to use this tool: for age prediction based on names using the Agify service. It mentions the 'Free Tier' and 'updates monthly' to set expectations, but does not explicitly state when not to use it or name alternative tools for similar demographic data (e.g., other international tools like 'genderize' or 'nationalize').

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