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

With no annotations provided, the description carries the full behavioral burden. It discloses that the URL is short-lived, single-device, requires no login/session, and lasts ~5 minutes. This is meaningful behavioral context beyond a bare 'get stream' statement, though it does not address failure modes or side effects like whether streaming is stopped or device resources are consumed.

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 three sentences, front-loads the core purpose, and every sentence adds value: what the tool does, the behavior of the returned URL, and when to use it. No filler or redundant restating of the tool name.

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 single-parameter tool with no output schema, the description is complete enough to invoke and interpret the result. It explains what is returned (a viewer URL), how to use it (open directly), the authentication situation, the time limit, and the human-supervision use case. Nothing essential 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 input schema already fully documents the only parameter 'udid' with a description, so the baseline is appropriate. The description adds no new parameter-level meaning, but none is needed because 'udid' is simple and well-covered by the schema.

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 a specific action ('Get a LIVE video-stream link') and resource ('an iOS device'), with an explicit contrast to ios_screenshot. The distinction between live video and a single frame makes the tool's purpose unmistakable, even among many iOS siblings.

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 explains the intended use case: letting a human supervise the agent in real time. It also explicitly names ios_screenshot as the alternative for static frames. It does not enumerate all alternatives or edge cases, but the guidance is clear and sufficient for selecting this tool over the most similar sibling.

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