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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds real behavioral context beyond structured fields: a ~24-hour data lag with daily refresh, and the caveat that 'a zero can mean not reported' due to partial platform coverage. That partial-coverage warning materially affects how an agent interprets results.

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?

Three tight sentences, front-loaded with what the summary contains, then freshness, then the interpretation caveat. No filler; each sentence contributes either scope or behavior.

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-value documentation is not needed, and the description covers scope, freshness, and the zero-is-ambiguous caveat. The only mild gap is the absence of routing to/from the sibling analytics tools, a minor omission given the otherwise complete picture.

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 parameters (range enum and social_account_id) are already fully documented in the schema, including default and the analytics_history_limit behavior. The description adds nothing parameter-specific beyond restating 'for a date range', 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 ('summarize') and resource ('post performance for a date range') and enumerates the contents (period-over-period totals, daily changes, breakdowns by content format, top posts). This clearly delineates it from per-post tools, but it never names the closest siblings (get_post_analytics, list_post_analytics), so sibling differentiation is left implicit.

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?

The description implies the aggregate-view use case but gives no explicit when-to-use versus get_post_analytics or list_post_analytics, and no exclusions. The freshness note ('Numbers appear about 24 hours after a post goes live') weakly signals when the data will be available but is not phrased as usage guidance.

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