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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds 'Returns timestamped data points with totals,' but this return behavior is largely already provided by the output schema. No additional behavioral context is given about pagination, auth token/domain requirements, or other edge cases beyond what the schema already exposes.

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 with no filler. It front-loads the core purpose, states the return shape, and ends with a clear use case. Every sentence earns its place.

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 rich structured context—100% schema description coverage for all 29 parameters, a read-only annotation, non-destructive annotation, and an output schema—the description needs only to orient the agent toward purpose and typical use. It does that clearly. Nothing necessary for correct invocking is missing when the schema and annotations are considered alongside it.

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 100%, so the baseline is 3. The description's grouping mention maps loosely to the 'interval' parameter but adds no meaning beyond the schema's interval enum and description. It does not compensate for or enrich the parameter semantics beyond what the input schema already provides.

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 a specific verb and resource: 'Get time series analytics data grouped by hour, day, week, or month.' This distinguishes it from sibling analytics tools like get_breakdown or get_overview by emphasizing time-series grouping and timestamped data points. It does not explicitly name an alternative tool, so it falls short of a 5.

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 clear usage context: 'Use for trend analysis and charting.' This tells the agent when the tool is appropriate. However, it does not give explicit when-not-to-use guidance or name a sibling tool as the alternative, so it does not reach a 5.

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