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

With no annotations, the description fully discloses behavior: it explains that the TV or receiver owns the volume, that absolute controls are unavailable, and that 'get' returning 0 and 'set' failing is normal. It also notes the tool doesn't wake the TV, providing critical context for troubleshooting. This exceeds the typical level of transparency.

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 compact and highly informative, front-loading the actionable instruction to use 'up'/'down'. Every sentence adds value, from the HDMI limitation to the tvOS-specific behavior and the warning about the TV wake state. No fluff or repetition.

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 tool's complexity (3 parameters, one enum, no output schema), the description is exceptionally complete. It addresses the why and how of each operation, preempts common pitfalls (like expecting absolute levels to work), and provides the exact environment context (tvOS 27) for reproducibility. Nothing an agent needs 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 covers all parameters with descriptions and an enum for op. The description adds value by explaining the semantics of 'get'/'set' and the expected failure behavior, but the underlying parameter meanings are already clear from the schema, so additional explanation isn't strictly necessary.

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 clearly states the tool's purpose: changing an Apple TV's volume via remote control keys. It explicitly distinguishes between the working operations ('up'/'down') and the non-functional absolute operations ('get'/'set'), and explains why, making it distinct from any sibling tools like ios_tv_button or ios_tv_power.

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 explicit guidance on when to use each operation: use 'up'/'down' for volume control, and avoid 'get'/'set' because they don't work with HDMI-connected TVs. It also warns against building a level slider on 'get' and mentions that the tool does not wake the TV, so an agent knows what to expect.

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