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

With readOnlyHint and openWorldHint already signaling a safe, externally-fetching read operation, the description adds meaningful context: it returns ready-to-use selectors rather than raw HTML and positions the tool as a discovery step. It does not discuss rate limits or API credentials, but the annotation coverage lowers the bar and the added output behavior is valuable.

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 carry the full meaning with no filler. The main behavior and output format are front-loaded, and the second sentence provides a concrete usage workflow and sibling reference. The API link in the first sentence is useful rather than decorative.

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?

Despite having no output schema, the description supplies a JSON skeleton and enough semantic detail to know what each element object provides (a selector). It also names the relevant sibling workflow. It does not fully specify the inner shape of each element or behavior across all five params, but the schema descriptions cover the parameter side.

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?

Schema description coverage is 100%, so the baseline is 3. The tool description does not add param-specific explanations, but the schema fully documents url, wait_method, wait_value, proxy_country, and sleep_seconds. The mention of 'ready-to-use selector' hints at output semantics rather than input parameter meaning.

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 names the resource ('interactive elements'), the action ('Fetch a page... and return'), and the output format ('JSON {url, count, elements:[...]} instead of raw HTML'). It also names fetch_html, which distinguishes it from a sibling tool that returns different content.

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 explicit context for when to use the tool: 'Use it to discover what to target, then drive the page with the `steps` param of fetch_html.' This effectively routes the agent to a sibling for the follow-up action, but it does not explicitly state when not to use the tool or compare against fetch_parsed or google_search.

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