Count users

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

With no annotations, the description carries the full burden of describing behavior, and it does so clearly: it returns a count, applies to a realm, and optionally filters by a search term. It is a read-only operation with no side effects, and the return concept ('number') is clearly stated. Some details such as exact matching semantics of the search term are not disclosed, but for a simple count tool this is sufficient.

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 a single sentence that front-loads the primary action and resource. Every phrase is meaningful and adds context: the count of users, the realm scope, and the optional search filtering. No filler or redundancy exists.

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 two-parameter, read-only count operation with full schema coverage, the description covers the essential context: what the result is and what data it operates on. Since there is no output schema, the description manages to state that a count is returned. It does not discuss edge cases such as zero matches or invalid realm names, but those are not necessary for basic invocation.

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 100%, so the schema already defines both parameters and their purpose. The description's 'matching a search term' phrase aligns with the 'search' parameter but adds little beyond what is already available. No additional meaning about format, boundaries, or interactions between realm and search is provided.

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 the exact operation: 'Return the number of users' scoped to a realm. This distinguishes count_users from sibling tools like list_users (which lists user objects) and get_user (which fetches a single user). The optional search clause adds operational specificity without ambiguity.

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?

There is no explicit guidance about when to use this tool versus alternatives. The description implies that it is used when a count is needed rather than a detailed list, but it does not state that list_users should be used when user details are required. The agent must infer the use case from the tool's name and description alone.

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