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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description does not contradict them. It adds the key behavioral detail that this tool counts but does not return rows, which is helpful. It does not discuss output format or potential rate limits, but an output schema exists, lowering the burden.

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 well-structured sentence front-loads the operation and scope, then adds the no-rows caveat and use cases with no filler. Every word earns its place.

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?

Given the presence of an output schema and safety annotations, the description covers the essential behavior, use cases, and the relationship to list_mentions. The only gap is that parameter semantics are not self-contained, instead depending on the sibling tool's filter definitions, which is acceptable but less complete for standalone use.

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 only 38%, so the description must help. It does so by pointing to list_mentions and asserting these are the same filters, which tells the agent to look there for parameter semantics. However, it does not describe individual parameters like statuses, scoreBuckets, or includeLowRelevance, leaving some reliance on the sibling's documentation.

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 states a specific verb and resource: 'Count mentions matching the same filters as list_mentions'. It explicitly differentiates from the sibling list_mentions by adding '(without returning the rows)', so an agent can immediately distinguish the two tools without opening either schema.

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 gives clear context: it is useful for pagination and dashboards, and it names list_mentions as the tool that returns rows. While it does not spell out a hard when-not-to-use rule, the contrast with list_mentions is stated clearly and sufficiently implies when the count version is preferred.

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