Katzilla MCP

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

The description adds valuable behavioral context beyond annotations: it specifies the data source ('NASA APOD (Public Domain)'), update frequency ('updates daily'), and return format details ('Katzilla envelope with quality scores and citation'). Annotations cover read-only, non-destructive, idempotent, and open-world hints, so the description complements these with practical usage insights without contradiction.

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 highly concise and well-structured: it front-loads the core purpose, includes key details (source, updates, return format) in a single sentence, and avoids redundancy. Every sentence adds essential information without waste, making it efficient for an AI agent.

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 low complexity (1 optional parameter), rich annotations (read-only, idempotent, etc.), and the presence of an output schema (implied by 'Returns the Katzilla envelope'), the description is complete. It covers purpose, usage, behavioral traits, and output structure adequately, leaving no significant gaps for the agent to operate effectively.

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, clearly documenting the 'date' parameter. The description adds minimal semantics by mentioning the parameter is optional and for a specific date, but does not provide additional details like format examples or constraints beyond what the schema already states. This meets the baseline for high schema coverage.

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 with specific verbs ('Get NASA's Astronomy Picture of the Day') and resource ('APOD'), and distinguishes it from siblings by specifying its unique astronomy focus and daily updates. It explicitly mentions the optional date parameter, making the scope precise.

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 usage ('optionally for a specific date; omit for today') and implies when to use it (for retrieving APOD data). However, it does not explicitly state when not to use it or name alternatives among siblings, such as other space-related tools like 'nasa-asteroids' or 'nasa-images', which could help differentiate further.

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