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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) by disclosing the async job model, immediate job-ID return, polling cadence, per-URL capture reservation at job start, refunds for failed URLs, and 24-hour link expiry — all operationally critical and not derivable from structured fields.

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?

Four tight sentences, front-loaded with purpose and capped size, then the polling protocol, then the billing/refund rule, then the return format. Nothing is redundant and each sentence carries distinct operational 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?

With no output schema, the description compensates by explaining what is returned (a job ID at once, no inline images) and how to retrieve results (get_batch_status plus 24-hour download links). Nothing needed to invoke and follow through is missing.

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 ranges, defaults, enum values, and interactions (device overrides width/height; quality ignored for png) are already documented in the schema. The description only adds the 'same options applied to every URL' batching semantic, so the baseline 3 is correct.

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?

States a specific verb (Capture) and resource (URLs), plus the batching scope ('up to 50 URLs with the same options in one background job'), which cleanly separates it from the single-URL sibling take_screenshot.

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?

Prescribes the follow-up workflow explicitly: call get_batch_status every 2-5 seconds until the job is completed, and notes results come back as download links rather than inline images. It never explicitly states when to prefer take_screenshot instead of batching, so it stops short of full when/when-not routing.

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