Katzilla MCP

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, covering safety and idempotency. The description adds valuable context beyond this: it discloses the external source ('is.gd'), its free nature, daily update frequency, and the specific return format ('Katzilla envelope' with quality scores and citation details), enhancing transparency 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 front-loaded with the core purpose in the first sentence, followed by supporting details (source, updates, return format). Every sentence adds value: the second explains the service, and the third clarifies the output structure. It's efficiently structured with zero wasted words.

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 (one parameter, simple operation), rich annotations (covering safety and idempotency), and the presence of an output schema (implied by 'Returns the Katzilla envelope'), the description is complete. It adequately explains the tool's purpose, source, update frequency, and return format, leaving no gaps for an agent to understand its use.

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?

Schema description coverage is 100% with one parameter ('url') fully documented in the schema. The description mentions 'long URL' but doesn't add significant semantic details beyond what the schema provides (e.g., no constraints on URL length or format). This meets the baseline of 3 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 specific action ('Shorten a long URL') and resource ('using the is.gd URL shortening service'), with explicit differentiation from siblings like 'utilities__fetch-url' (which fetches URLs) and 'utilities__qr-code' (which generates QR codes). It avoids tautology by elaborating beyond the tool name/title.

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 usage context: it specifies the service provider ('is.gd'), notes it's 'Free to use', and indicates 'updates daily' for freshness. It implicitly distinguishes from siblings by focusing on URL shortening, though no explicit 'when-not' or alternative tool is named, but the context is sufficiently clear for this standalone utility.

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