snapshot

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

No annotations are provided, so the description carries full responsibility. It clarifies that the tool is read-only ('Read'), discloses the truncation limit (about 12,000 characters), and explains the marker-line output structure. It does not mention permissions or side effects, but 'Read' already implies non-mutation, and the truncation is a significant behavioral disclosure.

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 three sentences with zero wasted words. It front-loads the core action and content, then gives usage timing, then discloses output markers and truncation. Every sentence adds essential information.

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 parameters and no output schema, the description covers what it does, when to use it, and important behavioral constraints (truncation, marker lines). It is complete enough for an agent to invoke correctly, though it could theoretically detail how to parse the output further, but the marker-line note covers the key ambiguity.

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 zero parameters, which makes parameter semantics non-applicable. Per the rubric, this case receives the baseline of 4 because there is nothing 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 states a specific verb-resource pair ('Read the current page as an accessibility tree') and enumerates the content types (headings, text, links, buttons, fields with roles and names). This makes it distinct from siblings like screenshot (visual) or scan, though it does not explicitly name an alternative.

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 advises taking a snapshot 'before clicking or filling' to learn the exact role and name to use. This provides clear context for when to use the tool, but it does not mention when not to use it or point to sibling alternatives.

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