Read visibility over time

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

The annotations already establish readOnlyHint=true, so the read-only nature is covered. The description adds meaningful behavioral context by explaining the grain of the data and what each row reports, going beyond the annotations. It does not mention pagination or exact output fields, but those are partly covered by the schema's cursor parameter.

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?

Two compact sentences, no filler. The first sentence explains what the tool returns, and the second gives routing guidance to the alternative tool. All information is front-loaded and useful.

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?

For a read-only, fully optional-parameter tool with a complete input schema, the description gives enough conceptual context about the return value: row-level daily measurements with brand-named and position indicators. It is slightly short on exact output shape and pagination behavior, but the schema's cursor parameter and the description's row-level explanation cover most of what an agent needs.

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 all six parameters are already documented with defaults, ranges, and formats. The description adds a little context by tying rows to day, prompt, and assistant, which maps to startDate, endDate, promptId, and model, but it does not need to compensate much because the schema is complete.

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 states a specific purpose: it exposes the individual daily measurements behind the summary, with one row per day, prompt, and assistant, indicating whether the brand was named and its position. It also distinguishes itself from get_visibility_summary by calling this the raw record versus the headline number.

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 explicitly says when to use this tool ('call this to inspect the raw record') and when to use the sibling ('call get_visibility_summary for a headline number'). This gives an agent a clear decision rule without needing to inspect either schema.

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