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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description contributes real behavior — this is a poll that returns the report only once status is done — but leaves open what a not-done response looks like, whether polling repeatedly is expected, or whether credentials expire. Useful but not rich context beyond the annotations.

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 compact sentences, with the key fact (what it polls, what it returns) up front and no wasted prose. 'Free.' is terse and informative, though it is pricing metadata rather than invocation guidance.

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?

An output schema exists so return values need no explanation, and the description covers the happy path adequately. The gap is the parameter combination (delivery_id+key vs. result_url) and any non-done status behavior, which an agent needs to poll correctly.

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 coverage is 0%, so the description carries the burden; it does explain the provenance of delivery_id and key ('from the site_report result') and that result_url is an alternative. However, it never says which of the three parameters is actually required or how the two modes interact, leaving a real ambiguity for a tool with zero required parameters.

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 and resource ('Poll a site report') and ties it to the sibling site_report by saying the credentials come 'from the site_report result', which lets an agent place it in the async workflow. It stops short of explicitly contrasting with site_report, but the polling framing is unambiguous.

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?

Gives clear context for use: call it after site_report, using delivery_id and key (or result_url) from that result. It does not state when not to call it (e.g., before a report is submitted) or how often to retry, so the guidance is strong but not exhaustive.

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