page_a11y

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

With no annotations provided, the description carries the behavioral transparency burden. It discloses meaningful behavior: it pierces shadow DOM, only includes visible interactive elements, and returns current values. It could add an explicit read-only guarantee or limitations around iframes, but the snapshot language strongly implies a non-mutating operation.

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 two dense, front-loaded sentences with no filler. The first sentence states what is returned and key traits, and the second gives a direct usage recommendation.

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 snapshot tool with simple parameters and no output schema, the description adequately explains the returned content: refs, roles, accessible names, and current values. It could be more complete by explicitly linking the stable refs to sibling ref-based tools like page_click_ref, page_type_ref, and page_read_ref, but it is sufficient for an agent to invoke the tool.

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?

There are two parameters with 0% schema description coverage, and the description does not explain session_id or page_id. The names are inferable from the broader tool family, but the description adds no parameter-level meaning and does not compensate for the missing schema descriptions.

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 clearly states the tool's purpose: a semantic snapshot of visible interactive elements with refs, roles, accessible names, and current values. It differentiates itself from guessing CSS selectors, but it does not explicitly distinguish itself from the sibling tool page_snapshot, which could be confused with a generic snapshot.

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 gives a clear usage directive: use this instead of guessing CSS selectors, especially for shadow-DOM-heavy web-component UIs. It provides useful context for when to invoke it, though it does not name alternatives or state when not to use it.

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