ui.hold_read

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

With no annotations provided, the description carries the behavioral burden and does so well: it discloses the background-thread hold mechanism, the screen-comparison approach, what is returned (newly appeared tooltip text), and per-mode latency (~1s a11y vs ~6s OCR). It omits permission/auth needs and hold_ms defaults, keeping it from a 5.

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 tightly-packed sentences that front-load the core purpose, then the suitable scenarios, then the ocr tradeoff. No filler, though the density makes it slightly harder to scan.

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 7-parameter, no-annotation, no-output-schema tool, the description covers the return value and the ocr decision well but leaves most targeting parameters (x, y, selector, pkg, handle) and hold_ms unexplained. It is adequate but has clear gaps an agent must infer.

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 coverage is only 14% (only handle is described), so the description must compensate. It explains the ocr boolean meaningfully with timing and use-case, but leaves x, y, pkg, selector, hold_ms, and the x/y-vs-selector-vs-handle relationship undocumented, so it only partially compensates for the coverage gap.

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 states a precise verb+resource: long-press a target on a background thread, read the screen during the hold, and return the newly-appeared tooltip text. It clearly distinguishes this from siblings like ui.long_click (which just presses) and ui.get_text (which reads existing text), so an agent can tell them apart without opening schemas.

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?

It explicitly says when to use it (hover explanations, icon long-press menus, tips that only appear while held) and gives clear ocr=false vs ocr=true selection guidance with timing tradeoffs. It does not, however, name alternative sibling tools or state when-not to use it, so it falls short of a 5.

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