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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds substantive behavior beyond them: average_google_position is null when no keyword ranks in the top 50, location_id filters post-fetch so pages can come back short while next_cursor continues, and totals count all reports rather than the filtered subset. These are exactly the non-obvious traits a caller needs before invoking and paginating.

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 content is front-loaded with purpose and row shape, then the caveats, with no filler sentences. It is dense and slightly run-on in places ('total counts all reports'), but every clause carries information an agent needs.

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?

There is no output schema, so the description carries the return-shape burden and does so fully: it lists the row fields, the null condition, and the pagination/filter interaction. Nothing material for correct invocation is missing.

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 coverage is 100%, so the baseline is 3, but the description adds genuine meaning: it clarifies that location_id is applied after BrightLocal returns results (affecting page size and total semantics) and that cursor must come from next_cursor on the previous call. It stops short of stating any format details beyond that, so a 4 rather than 5.

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 opens with a specific verb and resource ('List Rank Tracker reports') and immediately enumerates the row content (location, schedule, latest run date, status, average Google position, keyword movement), which clearly separates it from the singular get_rank_tracker_report and from sibling list_* report tools. An agent can determine the output shape without opening any schema.

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 explicitly routes the agent to the alternative: 'Read a report with get_rank_tracker_report and its location_id.' It also explains the operational condition for paginating with cursor and the caveat that location_id filtering happens after fetch, which changes how a caller should interpret a short page.

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