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

Annotations already establish readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered. The description adds genuinely non-redundant behavior: required GA connection and property selection, plus the plan-tier difference where free plans return only a landing-page preview while paid plans return the full list. Return granularity is not fully specified, but this is meaningful disclosure 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?

Dense but front-loaded with what the tool returns before moving to prerequisites and tier limits. Every clause carries information, though the single long sentence piles several metric groups together and could be segmented for faster scanning.

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 carries the burden of describing returns, and it does: metrics, comparison framing, landing pages, and AI-referral visits, plus setup prerequisites and free-vs-paid output limits. An agent has enough to call it correctly and set expectations for the response.

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. The description adds interpretation beyond the schema by framing 'days' as a comparison against the previous equally-sized window ('the last N days compared with the previous N days'), which clarifies the resulting metrics are deltas, not raw values.

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 ('Get Google Analytics 4 data for one of your sites') and enumerates exactly what is returned: organic sessions, engagement rate, key events, users, comparison window, top landing pages, and AI-assistant referrals. This is clearly distinguishable from the Search Console and backlink siblings.

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 concrete prerequisites: Google Analytics must be connected in DidYouSEO and a GA4 property must be chosen for the site. It also sets scope with 'for one of your sites.' It stops short of naming an alternative tool or an explicit when-not-to-use condition, so it is clear context rather than full routing guidance.

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