API key status

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context by noting the tool is 'Free' and that it 'confirm[s] the API is reachable,' going beyond the structured annotations. No contradiction exists.

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 two sentences: the first states the purpose, the second gives usage guidance. It is front-loaded, concise, and contains no redundant or filler content.

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 empty input schema, an existing output schema, and strong annotations, the description fully covers the tool's purpose, when to use it, and its cost ('Free'). There are no missing critical details for a zero-parameter status check.

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 tool has exactly zero parameters, and the schema coverage is 100% by default. There is nothing for the description to add regarding parameters, so a baseline score of 4 is appropriate.

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 uses a specific verb 'Check' and clearly names the resource: 'Elfa API key tier, credit usage and remaining requests, and confirm the API is reachable.' This distinguishes it from sibling data-related tools and leaves no ambiguity about what the tool does.

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 explicit usage guidance: 'Call this first when a request fails with an auth or credit error.' This is clear context for when to use the tool, but it doesn't mention when-not to use it or name alternative tools, though none are obvious given its diagnostic role.

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