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

Annotations already establish readOnlyHint=false and destructiveHint=false, so the safety profile is known. The description adds meaningful behavioral detail: music continues in to_room, stops in from_room, and grouped rooms keep playing. This is valuable context that goes beyond the annotations and helps predict side effects.

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 entire description is one efficiently structured sentence. It leads with the action, then specifies the effects on both rooms and includes the important grouped-room exception without any wasted words.

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 tool with no output schema and simple semantics, the description covers the core behavior and an edge case (grouped rooms). It does not describe return values or error handling, but these are typically not essential for such a direct command, so the definition is near-complete.

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 value by linking the parameters to their operational roles ('music continues in to_room' and 'stops in from_room') and clarifies the grouped-room caveat for from_room. This is more than the schema alone provides.

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 uses a specific verb ('Moves') and resource ('what's playing') and clearly distinguishes the behavior from siblings like play_music or switch_source. It states the outcome for both rooms and even handles the grouped-room nuance, making the tool's purpose unmistakable.

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 description clearly implies when to use the tool: when the user wants to transfer currently playing audio from one room to another. It provides the behavioral context (music continues in to_room, stops in from_room) but does not explicitly mention alternatives or when not to use it, so it falls just short of a 5.

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