snapshot

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

No annotations are provided, so the description carries the full transparency burden. It discloses that the output is a structured, compact view and only includes visible interactive elements, which is useful behavioral info. However, it does not explicitly state that the tool is read-only, nor mention potential caveats like handling of iframes, dynamic content, or page load states, leaving some behavioral gaps.

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 sentences, front-loaded with the tool's purpose and contents, and the second sentence adds clear usage guidance. No fluff or redundancy.

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?

With no output schema and 0 parameters, the description carries the burden of explaining return values. It lists the main content (URL, viewport, scroll position, interactive elements) and the usage context. It stops short of detailing exact data structure or edge cases, but for a simple 0-parameter tool this is quite complete.

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 tool has 0 parameters and an empty schema, so the baseline is 4 per the rubric. The description adds no parameter info because none is needed; nothing is left undocumented.

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 what the tool does: it returns a compact structured view of the page including URL, viewport, scroll position, and visible interactive elements with selectors and rects. It also distinguishes itself from page_source by explicitly recommending snapshot for click decisions, making its purpose unambiguous and distinct from siblings.

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 says 'Prefer this over page_source()' and explains it is 'the cheap way to decide what to click.' This provides a clear when-to-use directive and names the alternative tool, giving strong usage guidance.

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