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

With no annotations, the description fully discloses key behaviors: it deliberately does not wake the TV (to avoid navigating away), it explains the distinct states of text: '' vs null, and warns that a null buffer usually indicates a display problem. This goes beyond typical descriptions and equips the agent with critical edge-case knowledge.

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 well-structured and front-loaded with the core purpose. Every sentence adds value: the focus prerequisite, the state disambiguation, the display issue, and the no-wake behavior are all relevant. It is concise despite its length, with 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?

The description covers the tool's purpose, prerequisites, behavioral nuances, and output interpretation (text vs null). Since there is no output schema, it takes on the burden of explaining the reply states, which it does thoroughly. Nothing essential is missing for an agent to invoke it correctly.

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 100%, with each parameter already explained (op enum meanings, text purpose, udid). The tool description does not add any parameter semantics beyond what the schema provides, so baseline 3 applies.

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 reads or writes the text field an Apple TV currently has focused, specifying the verb and resource precisely. It distinguishes itself from siblings by tying to the on-screen keyboard buffer and the prerequisite of having a focused field via ios_tv_button, making it unmistakable.

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?

It explicitly states the prerequisite (field must be focused, navigate with ios_tv_button) and explains when the operation goes nowhere. It does not name direct alternatives like ios_send_keys, but the context is clear enough for an agent to decide when to use it.

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