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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive). The description adds genuinely useful behavior beyond that: metrics are cumulative totals of posts published in each window rather than activity during it, deltaPct is null when the previous value is 0, and periods use inclusive from/exclusive to timestamps. These are non-obvious semantics an agent could not derive from annotations.

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?

A single dense paragraph that front-loads the core return fields and then layers the caveats. Every sentence carries information, though the run-on enumeration of return fields is slightly heavy; the front-loading keeps it usable.

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 no output schema, the description correctly carries the full return-shape burden and does so, enumerating metrics, deltas, and topVideo plus the cumulative-totals caveat. What is missing is the brandId parameter's meaning and any mention of which system it reads from, but the core contract is complete.

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 0%, so the description must compensate. It does explain the days parameter (allowed values 7|30|90 and a default of 30 that the schema does not state), but brandId is never mentioned, leaving half the parameters undocumented beyond their names.

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 description clearly states it returns aggregate totals (videoCount, views, likes, etc.) for videos published in the last N days, including previous-window comparison and topVideo. That is a specific resource+operation, and the 'Only video posts are included' line scopes it. It does not explicitly differentiate from sibling analytics tools like get_metrics_daily or get_top_performers, so it falls short of a 5.

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?

Usage is implied by the windowing language and the default-30 note, but there is no explicit statement of when to choose this over get_account_overview, get_metrics_daily, or get_top_performers. The agent must infer the routing from the sibling names alone.

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