Regional distribution

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

Annotations (readOnlyHint, idempotentHint, destructiveHint) already convey safety and non-destructiveness. The description adds behavioral context beyond annotations: it specifies the data time range (last 30 days), the output fields (count, share, affinityIndex), and explains the meaning of affinityIndex ('>100% = above-average interest, <100% = below'). This is valuable behavioral detail not present in 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 two sentences long, front-loading the main purpose in the first sentence. Every sentence provides essential information: first the core functionality, second the parameter details and cross-reference to sibling tool. No redundant or extraneous text.

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?

The tool has two parameters (both described), rich annotations, and no output schema. The description explains output fields (count, share, affinityIndex) and provides interpretation of affinityIndex. It references list_regions for name resolution. It does not mention potential pagination or limits, but the fixed 30-day window and single-phrase input make this acceptable for a query tool. Completeness is high for the complexity level.

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 input schema covers both parameters with descriptions (phrase and regionMode enum). The description adds a summary of regionMode ('all, cities, or regions/oblasts') and mentions mapping via list_regions, but this largely repeats schema information. Parameter semantics are adequately handled by the schema, so the description adds minimal extra meaning.

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 begins with 'Returns how demand for a phrase is distributed across regions over the last 30 days,' clearly stating the verb ('returns'), the resource ('demand distribution'), and the scope. It distinguishes itself from sibling tools like list_regions by mentioning how to map region ids to names, and the phrase 'across regions' differentiates it from other analytical tools.

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 does not explicitly state when to use this tool versus siblings like dynamics or top_requests. It provides some guidance via the regionMode parameter (all, cities, regions) and mentions using list_regions for name mapping, but lacks a clear when-to-use or when-not-to-use statement relative to other tools.

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