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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so safety is covered. The description adds genuinely new behavioral context: stations that cannot play in a browser are excluded from availability, and the response links out to the station's OndaCast page for listening.

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?

Lookup keys and returned fields are front-loaded in the first sentence, and the availability caveat follows logically. Minor waste: the station's OndaCast page link is mentioned in the field list and again in the closing sentence.

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?

An output schema exists, so the field enumeration is redundant but harmless; the description still carries the availability constraint that structured fields wouldn't express. Nothing essential for a correct call is missing apart from explicit sibling routing.

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% and the single parameter's description already gives both the slug form and the URL example. The description's "by slug or OndaCast page address" restates the schema without adding format, normalization, or error semantics (e.g. what happens on slug miss). Baseline 3 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?

States a specific verb and resource ("Get one radio station from OndaCast") plus the two accepted lookup keys (slug or page address), and enumerates the returned fields. It doesn't name search_stations as the way to discover a slug, so the singular-vs-plural split with its sibling is left implicit rather than stated.

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 is for listening to or playing a station" implies the intended use case, and the note that non-browser-playable stations are unavailable hints at failure conditions. But there is no explicit when-to-use/when-not guidance and no routing to alternatives such as search_stations for finding a station first.

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