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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds that it returns historical lines and how dates filter, but does not disclose additional behavior such as pagination, limits, or sorting. No contradiction 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 a single, well-structured sentence that front-loads the purpose, includes a concrete example, and mentions key parameters. No redundant words or filler.

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 the simplicity of the tool (3 params, no output schema), the description adequately covers the purpose, required parameter, and filtering logic. It does not explicitly differentiate from siblings, but the tool name and description together provide enough context for a straightforward read operation.

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 description coverage is 0%, so the description must compensate. It clarifies that diaryId is required and explains the conditional behavior of the two date parameters (both must be provided to filter). This adds meaningful semantic context beyond the bare schema, though it omits date format or inclusivity details.

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 it provides historical lines of a diary track (with glucose series as example), which is specific enough to distinguish it from generic diary or log tools like dietaai_diary and dietaai_log. However, it lacks an explicit verb such as 'list' or 'get', so the action is implied rather than stated.

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?

It specifies that diaryId is mandatory and that start_range_date and end_range_date filter the interval only when both are provided. This tells the agent when to supply parameters but does not explicitly mention when to use this tool versus alternatives like dietaai_log or dietaai_diary, nor any exclusions.

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