aua_screen_action

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

Annotations already declare readOnlyHint=false, openWorldHint=true and idempotentHint=false, so the mutation and non-idempotence profile is covered. The description adds one genuinely new behavioral constraint, the auth-takeover block, but says nothing about how tap/swipe coordinates are interpreted or what side effects the toolbar actions (home, back, refresh, save) have.

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?

Two short sentences with no filler, so it is concise, but the brevity comes at the cost of under-specification rather than tightening a complete statement. The blocking constraint is placed after the vague purpose sentence rather than front-loaded.

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 four-parameter tool with two enums, zero schema documentation and no output schema, the description leaves the core semantics unresolved: which actions need x/y, whether direction is required for swipe, and what tap versus press_button means. Only the auth-takeover restriction is fully explained.

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 0% across four parameters, so the description carried the full burden and added none. It never mentions x/y coordinate meaning, when direction applies (presumably only for swipe), or what each of the six action enum values does.

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 names two loose categories ("preview toolbar" and "pointer actions") that map only vaguely to the six enum actions, and it never explains what a "preview toolbar" is. It overlaps almost entirely with siblings aua_tap, aua_swipe and aua_press_button without giving any basis for choosing between them.

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 only guidance is the exclusion "Blocked during authentication takeover", which is useful but narrow. There is no statement of when to use this tool rather than aua_tap, aua_swipe, aua_press_button or aua_screen, all of which appear to do overlapping work.

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