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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds valuable behavioral context such as the cap of 750 distinct groups, the inclusion of total record count, and the top-N groups based on sort. No contradictions with annotations.

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 front-loaded with the core purpose, followed by examples and response structure. Every sentence earns its place, with no fluff or repetition of schema details.

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 11 parameters and no output schema, the description explains the core filtering/grouping logic and the key response fields. It does not cover every parameter in depth, but it gives enough context for an agent to select and invoke the tool correctly for common use cases.

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. It names the filter dimensions (archive, source type, event type, event place, year range) and lists group_by options, but leaves parameters like min_count, number_show, lang, and exact sort behavior only partially explained. The enums in the schema help fill some gaps.

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?

Description uses a specific verb ('Returns') and identifies the resource as record counts grouped by one chosen dimension, with concrete examples. It clearly communicates the tool's core function, though it does not explicitly differentiate it from sibling stats tools like get_record_stats or get_event_type_stats.

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?

Provides explicit usage guidance: 'Use this endpoint to answer questions such as...' with examples like 'how many marriages per year in Amsterdam?'. It does not mention when not to use it or name alternative tools, but the context is clear.

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