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

Annotations already cover the read-only/idempotent safety profile, but the description adds critical behavior beyond them: on Android 13+ the OS blocks this path, so it returns an empty-clipboard sentinel rather than throwing 'No shell command implementation.' This is exactly the kind of failure-mode disclosure an agent cannot infer from structured fields.

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?

Purpose is front-loaded in the first sentence, followed by the platform constraint and the workaround. The sentences are dense but each carries information; minor verbosity in the 13+ explanation keeps it from a perfect score.

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-param read tool with no output schema, the description supplies the return behavior (empty sentinel vs error) and the platform caveat, so nothing an agent needs to call and interpret 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 description coverage is 100% for the single udid parameter, so the schema already carries parameter meaning. The description adds no syntax or format detail beyond it, making the baseline 3 correct.

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 (read) and resource (clipboard content) scoped to an Android device, and implicitly contrasts with the sibling device_clipboard_set. An agent can distinguish it from other device_* tools without opening the 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?

Explicitly states when the tool works (Android 12 and earlier) and when it does not (Android 13+), and names the alternative (set via device_clipboard_set and paste directly). Both the condition and the recommended workaround are spelled out.

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