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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds two real facts: the window is fixed at the last 30 days and the payload comes back as short Markdown. It does not say how short, what metrics are included, or whether output is truncated, which matters for a context-window-targeted tool.

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 short sentence with no filler, and the two most decision-relevant facts (30-day window, Markdown format) are front-loaded. It is terse to the edge of under-specification, but nothing in it is wasted.

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?

For a one-parameter read-only tool with no output schema, the description covers the essentials: fixed window and return format. It leaves unclear what analytics content the document actually contains and how large it is, which is the main open question for a tool explicitly aimed at context windows and one of a dozen analytics siblings.

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% and the single site_key parameter is already documented in-schema, including its cross-reference to list_sites. The description adds nothing about the parameter, 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?

"The last 30 days as a short Markdown document" conveys the output shape and window, but it is a noun phrase with no verb or resource — the agent must infer from the name and title that this retrieves site analytics. With siblings like get_site_summary, get_site_analytics, and get_agent_report, there is no differentiation at all, so distinguishing it requires opening the 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?

"for context windows" implies a use case: call this when you need compact text to feed an LLM rather than structured data. That is a genuine (if terse) usage hint, but it never names an alternative or states when-not to use it versus get_site_summary or get_site_analytics, which overlap heavily.

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