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

With no annotations provided, the description carries the full burden. It discloses the read behavior, the return type (UTF-8 text or empty string), and a specific error condition ('no HID available' on iOS 17.x / no-tunnel). It does not mention permissions or side effects, but for a simple read operation this is adequate.

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 concise, front-loaded sentences. The first sentence states the primary action and key characteristics, the second covers the return value, and the third addresses the known limitation. No wasted words.

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 simple 1-parameter read tool with no output schema, the description explains both the expected return (UTF-8 text or empty string) and the error condition. It lacks an explicit mention of what HID stands for, but the tool name and sibling set provide sufficient context.

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% and the only parameter 'udid' is already described as 'iOS device UDID'. The description adds no additional meaning about the parameter, which is acceptable given the high schema coverage.

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 uses the specific verb 'Read' and clearly identifies the resource as 'device clipboard (pasteboard)'. It further distinguishes the mechanism ('via the system clipboard service') and highlights unique characteristics ('no automation session needed, no app foregrounding'). This sets it apart from sibling tools like ios_get_pasteboard or device_clipboard_get.

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 implies when to use this tool: when you need to read the clipboard without an automation session or app foregrounding. It does not explicitly name alternatives or exclusions, but the context is clear enough for an agent to infer appropriate usage.

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