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

Annotations already declare read-only, idempotent, non-destructive, and closed-world. The description adds genuine value on top: it discloses the returned payload (hosts, end time expressed in the show's own time zone, carrying stations, OndaCast page links) and the point-in-time constraint of "on air right now," which no annotation conveys.

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?

A single sentence that front-loads the action and scope, then enumerates the return payload, ending with the filters. No filler and no repetition of the title.

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?

With an output schema present, return values need not be spelled out, and annotations cover safety; the description still goes further by flagging the time-zone nuance. Only minor gaps remain, such as the absence of any note on result limits or empty-result behavior.

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 coverage is 100%, so the schema already documents genre, country (two-letter pattern), and limit. The description only restates that country and genre are optional filters and adds nothing about limit, defaults, or the maximum of 25; the 3 baseline applies.

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?

Specific verb and resource: "List radio shows on air right now in OndaCast's radio guide." The real-time scope plus the mention of hosts, end times, and carrying stations makes it immediately distinguishable from podcast/audiobook/chart siblings, though it never names one explicitly.

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 closing sentence notes that country and genre are optional filters, which implies how to use the tool but gives no explicit when-to-use guidance, no exclusions, and no pointer to an alternative tool (e.g. search_stations) for different needs.

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