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

The readOnlyHint annotation already indicates a non-destructive operation. The description adds context about distinguishing 'no data' from 'source down' and about using it before retries, which clarifies expected behavior beyond the annotation.

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 short but contains awkward phrasing and an unexplained trailing 'norm.' that seems out of place. The core idea is conveyed, but the structure could be cleaner and more professional.

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?

Despite having no output schema, the description provides enough context for an agent to know when and why to invoke the tool: check availability, distinguish no-data from source-down, and use before retrying failed calls. It is sufficient for a simple health-check endpoint.

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?

There are no parameters, and the schema coverage is complete by default. With zero parameters, there is nothing additional the description could meaningfully add about inputs, so the 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 clearly states the tool checks whether the I14Y catalogue answers, which identifies it as a health/availability check. It also distinguishes between 'no data' and 'source down' conditions, giving it a specific purpose beyond a generic status check. The wording is somewhat awkward but the core function is identifiable.

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 explicitly advises using this tool 'before retrying a failed call', which gives a clear usage condition. It does not name alternative tools, but the guidance is actionable and contextually relevant for a status-check tool.

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