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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered. The description adds the trailing-window scoping notion but nothing further — no pagination, latency, or result-size behavior. This matches the calibration bar for a read tool whose annotations carry the safety burden.

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?

A single front-loaded sentence with no filler, and because no output schema exists, enumerating the returned categories is legitimate content rather than padding. It is dense but each clause carries 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 usefully enumerates what comes back, and annotations cover the safety profile. It still omits when to call this rather than get_visibility, and gives no hint about the shape or granularity of the returned change objects.

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% for both parameters, so brand_id and window_days semantics are already fully documented, including the default of 30 days and the single-brand omission rule. The description's 'over the window' phrasing adds no syntax or format detail beyond the schema. 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?

The description states a specific resource — the change/delta report for AI visibility over a trailing window — and enumerates what it covers (mention-rate trend, answer churn, competitor site changes, new category pages). It is distinguishable from the static snapshot implied by get_visibility. However, there is no governing verb, so the agent must infer 'retrieve changes' from the enumeration.

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?

No when-to-use guidance is given, no exclusions, and no comparison to get_visibility (the obvious alternative for current-state data). The agent must guess whether this is a diff versus a snapshot based purely on the tool name.

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