aua_ready

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety and repeatability are covered by structured data. The description adds genuine value beyond them by disclosing that it will not start or restart services and that the returned observation should be reused, but it is silent on what happens when verification fails (exception vs. negative result) and on cost/latency.

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, no filler, with the verification scope front-loaded and the constraints following. Slightly telegraphic phrasing ("Verify unlocked screen, UiAutomator, foreground, display" reads as a compressed list) but nothing is wasted.

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?

There is no output schema, and the description only says to reuse "the returned observation" without indicating what that observation contains (device state, UI tree, screenshot when requested) or its shape. For a readiness gate whose output feeds subsequent calls, this leaves a meaningful gap, though the precondition list covers the core semantics.

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 single parameter 'screenshot' has 0% schema description coverage and its default of false is the only structured hint available. The description never mentions screenshots, so it does nothing to explain what enabling it captures or how it affects the returned observation; with low coverage the description was expected to compensate and does not.

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?

"Verify unlocked screen, UiAutomator, foreground, display and a nonempty tree" gives a specific verb plus an explicit checklist of preconditions, which is far more informative than the opaque name aua_ready. It does not, however, name or contrast itself with any sibling such as aua_doctor or aua_observe, so an agent must infer the boundary.

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 clause "Does not start/restart services" establishes one clear exclusion, and "Reuse the returned observation" implies the result should be carried forward rather than re-checked. There is no explicit statement of when to call this versus aua_doctor (diagnostics) or aua_observe (state capture), leaving the primary routing decision to inference.

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