local_player_control

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

With no annotations, the description carries the transparency burden. It discloses that this mutates/controls the local player, only works when LOCAL_PLAYER is enabled, and is not for hardware playback. It does not describe what status returns or the full effect of stop, but the main behavioral conditions are clear.

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?

Two concise sentences with no filler. The core purpose and prerequisite are front-loaded, and the sibling routing is handled in one clause. Every sentence earns its place.

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 two-parameter enum-driven tool, the description covers purpose, prerequisite, and sibling distinction. The main gap is that the status action's behavior/return value is not described and there is no output schema to fill that gap, but this is unlikely to prevent 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 description coverage is 100%, so the action enum and conditional url requirement are already fully documented in the schema. The description adds no parameter-specific meaning beyond what the schema provides, so the baseline score of 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 ('控制') and resource ('本机媒体播放器 mpv/vlc') and clearly distinguishes itself from sibling play_song by saying hardware playback uses that tool. An agent can readily tell which tool to use for local PC playback versus hardware playback.

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 context ('电脑端本地播放场景'), a prerequisite (LOCAL_PLAYER config must be enabled), and an explicit exclusion with the alternative tool (play_song for 小智硬件播放). This is strong, actionable routing guidance.

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