What this server can reach

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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds valuable context beyond annotations: 'Contacts nothing and costs nothing,' reassuring the agent that calling it is side-effect-free and cheap. It also clarifies the availability check is current ('right now').

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?

Three sentences with no wasted words. The core reporting function is front-loaded, followed by concrete usage guidance and a cost/contact note. Every sentence earns its place.

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?

For a simple, zero-parameter status tool, the description is complete: it states what is reported, when to use it, and what side effects to expect. Even without an output schema, an agent can infer that the result will indicate availability of the four named sources.

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 zero parameters and 100% schema description coverage, so there is nothing to explain beyond the baseline. The description's enumeration of the four checked sources adds semantic context about what the status result will relate to.

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 ('Report') and a precise resource ('which of the four Apple Podcasts sources are available right now'), enumerating each source. It clearly distinguishes itself from the sibling tools by being the only status/diagnostic tool.

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?

Provides explicit when-to-use guidance: call first if a tool has failed, or before planning work that depends on the library or owner analytics. This gives an agent a clear decision rule for invoking it.

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