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

Annotations already declare readOnlyHint=true and destructiveHint=false, which the description accurately reflects by stating it 'returns' data. The description does not add additional behavioral details (e.g., response size, error cases) but does not contradict the 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 a single sentence but is duplicated verbatim, creating unnecessary redundancy. It lacks structured usage notes or examples, though it is brief and to the point.

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, the description should explain what kind of data is returned (e.g., individual session timestamps, counts, or aggregates). It only says 'history of session times,' which is vague. Additionally, the 'platform' mention without a corresponding parameter adds confusion rather than context.

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 schema provides complete coverage for both parameters (start_date, end_date) with format and defaults. The description adds no extra semantic meaning to these parameters; it only vaguely references 'specified timestamps' without clarifying their role or relationship.

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 tool 'returns the history of session times' between specified timestamps, conveying a specific verb and resource. However, it mentions 'specified platform' which is not present in the input schema, introducing minor ambiguity about the tool's exact scope.

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 provides no guidance on when to use this tool versus sibling tools like shop_list_page_views or shop_list_orders. No exclusions, comparisons, or conditional usage hints are given, leaving the selection criteria entirely to inference.

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