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

Annotations already declare read-only, open-world, non-idempotent, and non-destructive behavior. The description adds useful context beyond those annotations by noting the data is real-time, that a sampling timestamp (observedAt) is returned, and that an availability reason is provided, which signals possible unavailability.

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, front-loaded with the core action and followed by the key return fields. It contains no filler and every sentence contributes to understanding the tool.

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 one-parameter read-only tool with annotations and an output schema, the description is largely complete: it identifies the data source, the live nature of the result, and the key returned pieces. It could be stronger by clarifying when to use this instead of get_station or search_stations, but that gap is more about usage guidance than core completeness.

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 schema already explains that stationId is a 12-character hex station ID or slug-id from the RoamDial directory. The description adds the notion of a 'verified station' but does not provide additional format details, examples, or constraints beyond what is in the schema.

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 states a specific operation: querying real-time ICY stream metadata for a station in the RoamDial directory. It distinguishes this from a general station lookup by emphasizing live now-playing metadata, but it does not explicitly name or contrast with siblings like get_station or search_stations.

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?

Usage is implied by the phrase 'real-time ICY stream metadata for a verified station,' suggesting it should be used when current track/show information is needed. However, there is no explicit when-to-use guidance, no exclusions, and no mention of alternatives among the sibling tools.

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