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

Annotations already declare readOnlyHint, idempotentHint and non-destructive behavior, so the safety profile is covered. The description adds genuinely new behavioral context: the numbers are network-reported and reflect their last refresh (numbers_as_of), which tells the agent results may be stale and how to remediate. It does not describe response shape or latency, keeping it below a 5.

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?

The metric inventory is front-loaded in the first sentence and the freshness caveat plus sibling pointer follow immediately. It is dense but every clause carries information; the only cost is a long opening sentence that is slightly list-heavy.

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 compensates by enumerating the returned fields, and the freshness note covers the main ambiguity for a read-only analytics tool. Nothing essential for correct invocation is missing, though it could note whether per-network breakdowns are always present.

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 'days' parameter is fully documented with its default and allowed values, so the schema does the heavy lifting. The description restates the 7/30/90 window but adds no format or edge-case meaning beyond that, which is the expected baseline.

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 names a specific verb+resource and enumerates the exact metrics returned (followers/growth per network, posts published, engagement totals, best posts, messages received/answered with reply rate and median reply time). It is clearly distinguishable from siblings like refresh_analytics and get_best_times.

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?

It explicitly routes the agent to refresh_analytics when fresher numbers are needed, and the 'last 7, 30 or 90 days' framing sets the reporting context. It stops short of stating when to prefer this over other analytics-adjacent siblings, but the alternative it does name is the one that matters.

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