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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the bar is lower, and the description still adds substantive behavior: the response echoes the resolved range plus today's date, and the agent is told to read those before assuming dates from training data. That is a concrete, non-obvious operational trait that annotations cannot express.

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?

Front-loaded with the return contents, then parameter modes, then the date-interpretation caveat. Three sentences with no filler; the final sentence is longer but carries a genuinely useful warning that would otherwise be lost.

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?

No output schema exists, so the description carries the burden of describing returns, and it does list the metrics and the echoed resolved range. Combined with annotations covering safety and a fully documented parameter schema, an agent has enough to call and interpret this correctly; only the sibling boundary remains unaddressed.

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 the schema already documents period defaults, the 7d/30d/90d options, date formats, and the YYYY-MM expansion. The description restates the period values and range combination but adds no syntax or precedence detail beyond the schema, so 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 (analytics overview) and enumerates the metrics returned: total posts, impressions, engagements, engagement rate, per-platform breakdown. It implicitly differs from per-post siblings, but never names get_account_analytics or get_post_analytics to make the boundary explicit.

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?

Explains how to drive the two date modes (rolling `period` vs `start_date`+`end_date`) and how to interpret the resolved range, which is real usage guidance. However, it gives no guidance on when to pick this overview tool over get_account_analytics, get_post_analytics, or get_posts_analytics, leaving the alternative-selection decision to inference.

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