how_many_customers

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds useful behavioral detail beyond annotations: it counts 'every customer' and 'breaks down by status,' which clarifies the output shape without needing to infer from schema.

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: the first gives natural-language examples for triggering the tool, and the second states the core behavior and a usage preference. Every sentence earns its place with no redundancy or fluff.

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 zero parameters and an output schema present, the description fully covers what an agent needs: the exact query intent, the scope ('every customer'), and the output feature (status breakdown). It also includes explicit sibling differentiation, making this a self-contained, complete description for its simplicity.

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 the baseline is 4 per the rubric. The description correctly focuses on behavior rather than parameter details, as there is nothing to document. It also points out the breakdown by status, which compensates for the lack of parameter-driven options.

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 ('counts') and resource ('every customer in Fieldwork'), immediately clarifying the tool's purpose. It also distinguishes itself from search_customers by explicitly naming it as the alternative for total-count questions.

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 explicitly states when to prefer this tool ('for total-count questions') and names the alternative ('search_customers'), giving the agent clear decision guidance. This goes beyond mere implication and directly addresses use-vs-alternative selection.

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