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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds substantial context beyond them: which metrics are only available account-wide, that the heatmap and top products depend on plan tier, and that `live` returns the last five minutes. It also discloses the failure behavior when the plan lacks analytics — exactly the kind of thing an agent needs before calling.

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 well front-loaded: the metric set comes first, then the branch on `catalogId`, then the plan prerequisite. Every sentence carries information, though the run-on em-dash construction of the middle sentences makes it slightly harder to scan than a bulleted branch would be.

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 an output schema present, return values need not be spelled out, yet the description still sketches the response shape for both modes. Combined with the plan gating, account-wide-only caveat and `live` semantics, an agent has everything needed to pick parameters and interpret the result.

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 baseline is 3; the description earns an extra point by explaining the consequence of `catalogId` (overview vs. catalog detail, heatmap, top products, live) rather than just naming the field. It adds only light context for `period`/`from`/`to` beyond the schema's own enum and date-format documentation, which already handles those.

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 concrete verb and resource — analytics (views, unique visitors, product clicks, time series) over a period — so the agent knows exactly what data comes back. However, it never distinguishes itself from the near-identically named sibling `show_analytics`, leaving the agent to guess which one to call.

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 explicit conditional guidance tied to `catalogId`: omit it for the account-wide overview with top catalogs/referrers/countries/devices/browsers, supply it for per-catalog detail, heatmap, top products and `live`. It also flags the prerequisite (a plan with analytics, with a graceful in-band failure message). The one gap is that it offers no guidance versus the `show_analytics` sibling.

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