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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's job is to add behavior beyond that — and it does: a 200-item cap, ordering (page goals by added order, then event goals by most-recently counted), hidden-goal semantics (excluded from breakdown but counted by a filter), special handling for public sites the user does not hold, and null/timezone semantics for first_counted/last_counted. This is genuinely useful context an annotation cannot carry.

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?

Every sentence carries real information, but it is delivered as one dense run-on paragraph with the key routing guidance (use get_site_summary/get_site_breakdown) buried mid-paragraph and field semantics piled on afterward. It is not bloated, but it is poorly front-loaded and hard to scan.

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?

There is no output schema, so the description must explain return values — and it does thoroughly: field-by-field meanings, ordering, cap, nulls, and the caveats field. Combined with the read-only annotations, an agent has enough to call it correctly, though the prose could be organized more clearly.

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% and the single parameter already documents itself ('A domain from list_sites, or any public site's'). The description only restates 'Name the site by its domain' without adding format or constraint detail beyond the schema, so the 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?

States a specific verb and resource ('A site's goals') and even gives the return shape { goals, count }, so the agent knows exactly what it gets back. It goes further than most by naming the sibling alternatives (get_site_summary, get_site_breakdown) for conversions over a range, which helps distinguish it. The phrasing is dense and run-on, but the purpose is unambiguous.

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 routes the agent elsewhere for range-based conversion queries: 'filter get_site_summary by a goal, or break get_site_breakdown down by goal.' It also states the domain must come from list_sites or be any public site's. It lacks explicit when-not-to-use framing, but the alternative routing is clear.

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