music_control

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

Beyond the annotations, it explicitly discloses that the change is 'additive, reversible player-state change', that macOS Automation permission is required, and that the response is the resulting now-playing state. This is exactly the kind of safety, prerequisite, and side-effect context annotations alone cannot convey, and it is consistent with destructiveHint=false.

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 dense sentences with zero filler: scope and action set first, then side-effect/permission/return semantics. Nothing to trim and nothing front-loaded incorrectly.

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 single-parameter tool with an output schema and non-destructive annotations, the description covers purpose, legal values, side-effect profile, permission prerequisite, and response shape. An agent has everything needed to call it correctly.

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?

With 0% schema description coverage and no enum declared in the schema, the description compensates by fully enumerating the legal values for the single `action` parameter. It stops short of explaining each action's edge behavior (e.g. what 'previous' does at track start), which keeps it from a 5.

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 ('Control Music playback') and enumerates the exact action set (play|pause|playpause|next|previous), which cleanly separates it from read-only siblings like now_playing and from playlist/volume tools (play_playlist, set_volume, music_search). An agent can identify what this does without opening the 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?

The action enumeration implies when each mode applies, and the parenthetical 'needs Automation access for Music' hints at a prerequisite. However, it never routes the agent to alternatives (now_playing for a read-only query, play_playlist for playing a named playlist, set_volume for loudness), nor states when not to use this tool.

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