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

Annotations already establish readOnly, idempotent, non-destructive, and non-open-world behavior. The description adds meaningful context beyond that: the TV must be awake and on the same network for its remote to answer, and unpaired TVs require ios_tv_pair_begin first. This explains failure modes and prerequisites that annotations cannot express.

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 front-loaded sentences: the first states the action and return fields, the second gives the troubleshooting trigger and network condition, the third gives the pairing prerequisite. No sentence is redundant.

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 zero-parameter discovery tool with no output schema, the description covers what is returned, when to call it, and the pairing prerequisite. Annotations cover the safety profile, so nothing critical 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?

There are zero parameters and schema coverage is 100%, so the baseline is 4. The description does not need to explain parameters, though it helpfully describes the return fields (name, identifier, paired status) since no output schema exists.

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 first sentence gives a specific verb (List) and resource (Apple TVs reachable from this host), and states the returned fields (name, identifier, paired status). It distinguishes this discovery tool from the remote-control siblings that act on an already-addressed TV.

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 tells the agent to start here when a remote call reports a TV cannot be found, explains the awake/on-network condition, and names ios_tv_pair_begin as the required next step for unpaired TVs. This covers when to use it and what alternative/prerequisite applies.

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