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

Annotations already declare this a safe read-only, idempotent, closed-world operation, and the description adds unusually rich behavioral context beyond that: it is a reconstruction not a transcript, the accessibility hint is never included, role words are English defaults, reading order is document order not VoiceOver's geometric order, and true speech is only readable on iOS 27+. This is exactly the kind of caveat an agent needs to trust and interpret the output.

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 and the flagged-defect list are front-loaded, followed by caveats; the structure is logical and every sentence carries real information. It is dense and long, but the length is justified by the number of genuine caveats rather than padding.

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 read-only, no-output-schema analysis tool, the description covers purpose, defect taxonomy, output interpretation limits, session prerequisites, and sibling relationship. An agent has everything needed to call it correctly and interpret the result without an output schema.

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%, so all three parameters (udid, element, onlyIssues) are already documented in the schema. The description reinforces scoping ("each element on the CURRENT screen") but adds no syntax or resolution detail beyond what the schema states, so the baseline 3 applies.

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 and resource — approximating VoiceOver announcements for each element on the current screen — and enumerates the exact defect classes it flags. It explicitly distinguishes itself from the sibling ios_accessibility_audit ("which reports Apple's own findings"), so an agent can route between the two without opening either 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?

Gives clear context: it operates on the CURRENT screen, complements rather than duplicates ios_accessibility_audit, and auto-starts an automation session if needed. It stops short of an explicit when-not-to-use rule (e.g., use ios_accessibility_audit alone when you want Apple's verdict), but the differentiation is strong.

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