Accessibility snapshot

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

With no annotations, the description carries full burden for behavioral disclosure. It only states 'Return a structured accessibility snapshot' without mentioning side effects, prerequisites (e.g., page must be loaded), idempotency, or potential costs. The phrase 'No screenshots needed' provides a minor clarification but not enough to compensate for missing transparency.

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 highly concise with two sentences: the first states purpose and output contents, the second provides usage guidance and a clarifying note. Every sentence adds value with no redundancy, and the key information is front-loaded.

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?

There is no output schema, so the description should detail the return format. It mentions 'roles, names, and [ref=..] handles' but gives no structure, ordering, or examples. It also does not mention prerequisites like having an active session or browser page, which are implied by sibling tools but not stated.

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?

The sole parameter 'session_id' has no description in the schema (0% coverage) and the tool description does not mention it at all. The agent receives no information about what session_id represents or how to obtain it, which is critical for correct invocation.

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 returns a structured accessibility snapshot with roles, names, and ref handles. It explicitly distinguishes from screenshot tools by saying 'No screenshots needed' and connects to sibling tools aethyn_click and aethyn_type, making the purpose specific and distinct.

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 provides explicit guidance on how to use the output: 'Pass those refs to aethyn_click / aethyn_type.' It implies the snapshot should be used when interaction handles are needed, but does not elaborate on when not to use it or contrast with all sibling tools, which prevents a score of 5.

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