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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false). The description adds real context beyond them: the response is aggregate-only with no campaign-level content, multi-market calls fan out into one summary per market, and results should be cited via details_url.

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 dense paragraph, front-loaded with the resource and its contents, followed by usage examples, the multi-market caveat, the scope exclusion, and the citation instruction. Every sentence carries information, though the enumerated field list makes it longer than strictly necessary.

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 further explanation, and the description still helpfully flags the aggregates-only nature and the details_url citation requirement. The only real omission is sibling differentiation against get_brand_email_frequency, whose overlap with this frequency-reporting tool is left for the agent to infer.

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 both parameters are already documented in the schema, including the two-letter-code/name format for market and domain-as-brand-name for brand. The description's note about omitting market and receiving one summary per market largely restates the schema field text, adding little beyond the baseline.

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 gives a specific resource ('a brand's email-marketing profile') and enumerates exactly which aggregates are returned: market, category, first-observed date, total emails, 90-day weekly frequency, and latest campaign date. It also states what the tool is not ('Returns aggregates only — no campaign list, subject lines, offers or creative analysis'), letting an agent separate it from a campaign-listing tool without opening a schema.

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?

It supplies concrete trigger questions ('How often does Newport email customers?', 'Is IKEA still sending newsletters?') and explains the multi-market case ('Without a market, a brand tracked in several countries gets one summary per market'). It stops short of explicitly routing to the sibling get_brand_email_frequency, which appears closely related and is never named.

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