apple_tv_capabilities

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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lowered. The description adds genuine value beyond them by enumerating the possible availability states (available, unknown, unavailable, unsupported) and clarifying the output scope as semantic rather than a raw UI dump.

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?

Three short sentences, front-loaded with the core purpose and each sentence earning its place: the enumeration clarifies return semantics and the final sentence blocks a plausible misreading. No 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?

With an output schema present, the description needn't explain return structure, and zero parameters removes schema burden. The description is complete for a read-only capability probe, though a brief note on when to prefer it over apple_tv_status would fully close the gap.

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 tool takes zero parameters, so there are no parameter semantics to document; per the rubric this sets a baseline of 4. The description correctly adds no misleading parameter information.

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 ('Return current availability of semantic Apple TV operations') and explicitly differentiates from sibling-style tools by declaring 'This is not a screenshot or UI-hierarchy dump.' An agent can immediately tell this is a capability-discovery tool distinct from apple_tv_screenshot and apple_tv_status.

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 negative framing ('not a screenshot or UI-hierarchy dump') implies when this tool is preferable, but there is no explicit when-to-use statement or guidance on querying it before attempting other operations. Usage is implied rather than stated.

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