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

With no annotations provided, the description carries the full burden and does so thoroughly. It discloses that this is a reconstruction, not a transcript; that the HINT is never included; that role words are English defaults; that reading order is document order rather than VoiceOver's geometric order; and that flagged issues are real while wording is indicative. This is exactly the kind of behavioral context an agent needs to avoid over-trusting 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?

The description is dense but every sentence earns its place: purpose, issue categories, fidelity caveats, sibling differentiation, and prerequisites. It is front-loaded with the core purpose and the most important caveat ('RECONSTRUCTION, not a transcript') appears early. It is long, but the complexity of the tool justifies the length.

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 tool with no output schema and no annotations, the description covers what the tool does, what it flags, its limitations, its relationship to a sibling, and its runtime prerequisite. An agent has enough to decide whether to call it and how to interpret the results. The only minor gap is the exact output shape, but the description's caveats make the output's nature clear enough.

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 100%, so the baseline is 3. The description adds value by explaining the 'element' parameter's resolution semantics ('resolved the same way ios_tap_by_label resolves it') and by clarifying that onlyIssues filters to flagged problems. It doesn't detail the udid parameter, but that is self-evident from the schema.

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 opens with a specific verb ('Approximate what VoiceOver would announce') and a clear resource (each element on the CURRENT screen), then enumerates the exact classes of issues it flags. It also distinguishes itself from ios_accessibility_audit by name, 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?

The description explicitly states when to use it (to approximate VoiceOver announcements and flag actionable issues) and names the complementary sibling (ios_accessibility_audit) that reports Apple's own findings. It also gives a hard platform constraint (iOS 27+ for real speech) and a session prerequisite, so an agent knows the conditions under which this tool is appropriate.

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