Recently played, live from Spotify

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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=true), and the description adds genuinely non-obvious behavior: the warehouse polls every 30 minutes, so results can include plays not yet persisted, and the call depends on a Spotify grant. It does not mention rate limits or ordering, which keeps it short of a 5.

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 short sentences, front-loaded with the resource and the key freshness caveat, then the alternative, then the prerequisite. No filler.

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 no output schema, the description still tells the agent what comes back (last plays, capped at 50, possibly unstored), what the freshness semantics are, and what auth is needed. Nothing essential to correct invocation is missing.

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 description coverage is 100%, and the schema already carries the default (10) and the maximum (50). The description's 'at most 50' largely restates that ceiling, so it adds little semantics beyond the structured field — baseline 3.

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 ('Spotify's own last plays, at most 50') and explicitly frames the scope as the live, not-yet-warehoused view. It names sibling get_plays as the contrasting tool, so an agent can distinguish this from every other history tool without opening a schema.

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?

Gives explicit when-to-use (recent/live plays not yet stored) and when-not ('For anything older use get_plays'), plus the prerequisite 'Needs the Spotify grant'. Both routing and the auth condition are stated rather than inferred.

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