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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context by specifying that the count is 'live' and enumerates the coverage categories, which informs the agent about the dynamic nature and scope of the data. This goes beyond the annotations without contradicting them.

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 description is two sentences, front-loaded with the primary action and resources, and every word contributes value. The usage guidance is appended naturally without redundancy. It is succinct and well-structured.

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?

For a simple, parameterless tool with no output schema, the description is complete. It states the return value (a live count of coverage) and the specific data categories, which is sufficient for an agent to understand what to expect. The annotations cover safety and idempotence, so no further behavioral caveats are needed.

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 has zero parameters, so there is nothing for the description to explain beyond what the schema already shows (an empty schema). The baseline for 0 parameters is 4, and the description appropriately does not invent parameter details.

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 uses a specific verb 'Return a live count' and explicitly lists the resources covered (course, scorecard, logo, architect, equipment, current-deal coverage). It clearly distinguishes this from sibling tools that retrieve individual records or search results, and the phrase 'instead of quoting hardcoded catalog sizes' further clarifies its unique role.

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 provides clear usage guidance: 'Use this instead of quoting hardcoded catalog sizes.' This indicates when the tool is appropriate and when it is unnecessary (when fresh counts are needed). It does not explicitly name alternative sibling tools, but the context is sufficiently clear for an agent to select it over content-retrieval tools.

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