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

Annotations declare a non-read-only, non-idempotent, non-destructive write with openWorldHint=false. The description adds real value beyond them: it discloses the side effect (credentials stored) and the downstream consequence (every other remote tool starts working for that TV). It does not cover failure behavior, which is the remaining gap.

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, each carrying distinct information (action, identifier constraint, success effect), front-loaded with the action and with zero 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 two-parameter, no-output-schema tool, the description covers the prerequisite, the required input linkage, and the success outcome. Nothing an agent needs to invoke it correctly 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?

Schema coverage is 100%, so both parameters are already documented. The description nonetheless adds a semantic constraint the schema does not encode: the udid must be the same identifier passed to ios_tv_pair_begin, which is a cross-call relationship rather than a field definition.

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 ('Finish pairing with an Apple TV') and explicitly ties itself to the sibling ios_tv_pair_begin, so an agent can distinguish it from the begin step and from the other ios_tv_* remote tools without opening any schema.

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?

Clearly establishes the prerequisite sequence (PIN comes from ios_tv_pair_begin) and the calling constraint ('pass the SAME identifier that call was given'). It does not state what to do on failure or whether it can be retried, but the when-to-use context is unambiguous.

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