音量を下げる

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the action (lower volume by one step) but does not mention side effects, reversibility, or any state changes beyond the immediate adjustment. For a simple mutation tool, this is acceptable but does not add extra context beyond the basic action.

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?

A single, concise sentence that front-loads the core action and magnitude. Every word is necessary; there is zero redundancy or fluff. The structure is optimally efficient.

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 the simple nature of the tool (one optional parameter, no output schema), the description fully captures the operation. The device parameter is documented in the schema, and the action is unambiguous. Nothing an agent needs to call this correctly is missing.

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?

The schema already documents the single optional 'device' parameter with 100% coverage, so the description adds no additional meaning beyond the schema. Baseline of 3 is appropriate as the schema handles parameter documentation and the description does not need to compensate.

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 ('下げる' – lower) with a clear resource ('音量' – volume) and specifies the action magnitude ('1段階' – by one step). This clearly differentiates from sibling tools like volume_up (increase), set_volume (absolute setting), and mute (mute state). An agent can immediately understand the tool's function without ambiguity.

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 implies usage for incremental volume decrease but provides no explicit guidance on when to prefer this over set_volume (absolute control) or mute. There are no exclusions or alternative recommendations, leaving the agent to infer the appropriate context. This is adequate but not explicit.

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