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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world). The description adds genuinely new behavioral context: this is an asynchronous retrieval that can return either a final result or in-progress state, which the agent cannot learn from the annotations alone. It stops short of describing terminal states or retry behavior.

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?

One front-loaded sentence with zero filler; the primary purpose (returning the result) precedes the conditional branch (progress if still running).

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 async dual-state behavior that matters most. The remaining gap is polling guidance (whether/how often to re-call), which is minor for a one-parameter read tool.

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% and the single parameter's schema text ("The check_id that check_page_visibility returned") already explains its origin and how to obtain it. The description adds no additional parameter meaning, so the baseline 3 applies.

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 ("Returns") and resource ("the result of an xfix search check"), and clarifies the async nature by noting it may return "progress if it is still running." It implicitly pairs with check_page_visibility ("started earlier") but never names that sibling explicitly, so an agent must infer the start/fetch relationship from context.

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?

"Started earlier" implies this is a follow-up call to a previously initiated check, which is useful implied guidance. However, it never names check_page_visibility as the initiating tool, nor says whether to poll repeatedly, how often, or what to do if the check never completes.

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