audit_parity

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral detail beyond annotations: it produces per-relation match/mismatch/uncertain verdicts and gives a concrete layout-drift example. No contradiction with annotations exists.

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 sentences with no filler: the first front-loads the core compare-and-flag behavior and the second concisely tells the caller what inputs to provide. The parenthetical enumerations are dense but necessary for disambiguation.

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?

The description is complete for a read-only comparison tool given its complex nested schema and absence of an output schema: it defines both inputs and the categories of output verdicts. A minor gap is that the relationship checklist's a/b element references and tolerance semantics are left implicit, but the overall context is adequate for correct invocation.

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?

With 0% schema description coverage, the description compensates by naming all top-level parameters (ios, android, checklist) and their broad shapes, and by enumerating the checklist relation domain (vertical centering, baseline/left alignment, equal gap/size, presence, truncation). It does not fully explain what a/b represent or how tolerance is used, but the schema structure plus this context is enough for a competent agent.

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 uses a specific verb ('Compare') alongside a clear resource ('iOS vs Android element snapshots') and explicitly names the expected output ('flag per-relation match/mismatch/uncertain'). The cross-platform scope distinguishes it from sibling audit tools such as audit_ios_screen or audit_page without ambiguity.

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 clearly states what should be provided ('Provide ios+android {elements,viewport} snapshots and a checklist[]') and includes an example that signals when the tool is appropriate (cross-platform layout drift detection). It does not explicitly name sibling alternatives to avoid, but the use case is well implied.

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