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

Annotations declare readOnlyHint=false and destructiveHint=false, so the write nature is already known. The description adds the clamping behavior ('values above 70 are clamped for safety'), which is useful and not present in annotations. However, it does not disclose other behavioral traits like error handling or whether the room must exist, so it only partially exceeds the structured info.

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 a single efficient sentence with the core action and range front-loaded. The clamping note is concise and valuable. It loses a point because it omits the alternative tool mention and contains an inconsistency regarding room optionality, but it is otherwise tightly written.

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 simple two-parameter write tool with annotations, the description provides enough to set volume correctly (range and clamping). However, the contradiction between the schema requiring 'room' and the description saying 'Omit for the default room' creates confusion. It also fails to mention the sibling adjust_volume, leaving the agent to guess which to pick. This is adequate but not fully 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 description coverage is 50% (only room has a description). The tool description adds semantics for volume by stating the range and clamping, which compensates partially for the missing volume description. It adds nothing for room beyond the schema, which already explains aliases and the optionality that conflicts with the required flag. Overall, it adds modest value.

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 specific action ('Set a room's volume') with a resource (room) and the value range (0-70). It clearly distinguishes the operation from siblings like set_mute or toggle_play_pause, though it does not explicitly contrast with adjust_volume. The clamping detail adds precision.

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 gives no guidance on when to use this tool versus alternatives. There is no mention of adjust_volume or any conditions that would favor one over the other. An agent must infer that this is for absolute volume setting, but the lack of explicit exclusions or prerequisites leaves a gap.

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