aggregate_customer

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

The description adds the key behavioral insight that 'nothing is precomputed', but it does not explicitly state that the operation is read-only or describe what happens with filters. Since no annotations are provided, the description carries this burden, but it is only partially met.

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, front-loaded sentence with no fluff. It communicates the core action and a critical behavioral trait efficiently.

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 output schema and no annotations, the description is incomplete. It does not specify the return format or how the optional sum is configured, and it does not explain the role of the filter parameter. The description covers the basic grouping idea but leaves significant operational details ambiguous.

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 coverage is 0%, so the description must compensate for parameter meaning. It explains that grouping is done 'by a property', but the 'optionally summing a numeric property' feature has no corresponding parameter in the schema, leaving agents confused about how to invoke it. The description adds minimal value for the existing parameters.

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 verb 'Group' with the resource 'Customer objects', and specifies the actions 'counting each group' and 'optionally summing a numeric property'. This distinguishes it from sibling search/get tools and other aggregate tools by explicitly scoping to Customer objects.

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 implies usage for aggregating customer data and notes 'Query-time aggregation', but it does not explicitly state when to use this versus search_customer or other aggregate tools, nor does it mention alternatives or exclusions.

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