play_song

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

With no annotations, the description carries the behavioral burden and does it well: it discloses automatic search/URL resolution, precise playback via song_id, and the ResourceLink return format that must be paginated through resource://read_from_http. It does not cover failure or error behavior, but the core data flow and consumption behavior are transparent.

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 compact and well-structured: purpose first, then trigger conditions, then call modes, then return/consumption details. Every sentence contributes useful information with 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?

Given no output schema and no annotations, the description compensates by explaining the return type (ResourceLink), how to consume it, and the two valid call paths. It is slightly incomplete regarding the required query/song_id condition and the boundary with get_play_url, but is otherwise adequate for correct invocation.

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 baseline is 3. The description adds meaningful cross-parameter context: query can contain singer + song name, and song_id + source form an exact-playback path after search_song. It stops short of explaining whether query and song_id are mutually exclusive or which combination is required.

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 clear verb-resource pair ('播放歌曲') and gives the exact user phrasings that should trigger this tool. It also implies a relationship with search_song by accepting its song_id, but it does not explicitly distinguish itself from sibling tools like get_play_url or local_player_control.

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 provides explicit when-to-use trigger phrases and two clear invocation modes: free-text query with auto-search, or exact song_id plus source after a prior search_song call. However, it does not state when to prefer get_play_url or local_player_control, nor does it clarify that at least one of query/song_id is effectively required.

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