netease_previous

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

Annotations declare readOnlyHint=false, openWorldHint=true, destructiveHint=false, which correctly signals this mutates playback state. The description adds nothing beyond that: it doesn't say what happens at the first track, whether the current track restarts, whether the queue is reordered, or what an error looks like with no active session.

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?

Seven characters is maximally concise and fully front-loaded, but it crosses into under-specification — there is no second sentence earning its place because there are no sentences at all beyond the bare action.

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 trivial one-parameter transport control with no output schema, a short description is defensible, and the annotations cover the safety profile. Still, nothing addresses the undocumented requestId or the playback-state preconditions an agent needs before calling it.

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 single required parameter requestId has 0% schema description coverage, and the description contributes nothing about it — no format, no origin, no idempotency meaning. With one undocumented parameter, the description fails to compensate for the schema gap.

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?

"播放队列上一首" states a specific verb (播放) and resource (队列上一首), so an agent can tell it navigates the playback queue backwards. It doesn't need to differentiate heavily because the sibling netease_next is self-evidently the inverse, but it never names that relationship 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?

There is no guidance on when to use this versus netease_next, netease_seek, or netease_play. No preconditions are stated (e.g., whether playback or a non-empty queue must already exist).

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