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

Annotations already establish read-only, idempotent, non-destructive behavior, so the description's job is to add context, which it does: the unit-cost model (13 units for a linked post, 1 for a plain post) and the meaning of a null limit (unlimited). Missing is anything about caching, freshness, or whether the reset date is returned as a timestamp, but the cost mechanic is the non-obvious behavior an agent needs.

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?

It front-loads the resource, packs the return fields and cost model into one parenthetical, then ends with the actionable recommendation. The middle clause is dense and could be split, but every sentence carries information an agent would otherwise have to guess.

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 parameters and no output schema, the description carries the full burden of explaining the response, and it does so: used, limit, remaining, reset timing, and connected-account count, plus the null-limit special case. Nothing essential for correct invocation or interpretation is missing.

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?

The tool takes no parameters, so the baseline is 4 and there is nothing for the description to disambiguate. It correctly spends no words on inputs and instead explains the returned fields.

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 the exact resource and its components: X post units for the month (used, limit, remaining, reset time) plus connected accounts versus the plan limit. An agent can tell this apart from list_accounts or get_analytics because it is explicitly about quota consumption rather than account data or performance metrics.

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 gives a clear condition: 'Check it before a batch of X posts so you don't hit the cap part way,' which is actionable pre-flight guidance tied to a concrete workflow. It stops short of naming alternatives or when-not-to-use cases, so it is strong context rather than a full routing rule.

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