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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description still adds real value by naming the exact status enum, the failure-reason field, the notion of 'changes left', and the polling loop semantics for asynchronous builds — behavior not present in 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?

Three front-loaded sentences with no filler: what it returns, when to call it, how to poll. The enumerated status list partially duplicates what the output schema likely carries, which is the only thing keeping it from a 5.

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 two-parameter status tool with an output schema and full annotation coverage, nothing an agent needs is missing: trigger conditions, async polling behavior, and the meaning of a failed state are all addressed. Return-format detail is correctly left to the output schema.

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 100%, so the baseline is 3 and the schema already documents both parameters. The description adds meaning beyond the schema for wait_seconds by describing the polling pattern ('call again while the status is building'), which the schema's 'holds the answer' phrasing does not convey as an invocation strategy.

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 ('Returns the state of an ad started with create_ad') and enumerates the exact state values, which lets an agent tell it apart from create_ad and request_change without opening a schema. The scope is unambiguous: it is a status read for an existing ad, not a mutation.

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?

Explicitly names the triggering situation ('when the user asks whether their ad is ready, or before saying that it is') and gives the follow-on protocol for the asynchronous case ('pass wait_seconds and call again while the status is building'). The only mild gap is that it does not say when to prefer request_change, but the read-vs-mutate split is already implied.

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