電源状態

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

Annotations already declare readOnlyHint=true, so the read-only nature is known. The description adds value by disclosing the behavior when the TV is in standby and unresponsive (returns that fact), and by enumerating possible states. This goes beyond the annotation and informs the agent of an edge case that affects output interpretation.

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 concise sentence that front-loads the main function and includes the essential edge case. Every word earns its place; there is no redundant or vague filler.

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 read-only tool with one optional parameter, the description covers the core behavior, example values, and the standby-response edge case. The lack of an output schema is acceptable since the description gives examples. It does not specify the exact return format (e.g., JSON vs plain string), but that is minor given the tool's simplicity.

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 only parameter (device) is fully described in the schema (coverage 100%), so the schema carries the semantic load. The description adds no additional context about the parameter, such as default resolution or format. With full schema coverage, the baseline of 3 is appropriate.

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 verb ('返す' – returns) and resource ('TVの電源状態' – TV power state), and lists concrete example values (Active, Active Standby, Screen Off). This clearly distinguishes it from sibling tools like power_on/power_off which change state, and from get_system_info which is broader. The purpose is unambiguous.

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 its use for querying power state but does not explicitly state when to use it over alternatives. For example, it does not mention 'use this to check if the TV is on before sending commands' or contrast with get_system_info. The context of siblings makes it obvious for a human, but the description itself gives no explicit when/when-not guidance.

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