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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior. The description adds useful behavioral context by stating the data is pre-aggregated across all years and specifying the return contents: total dollars and payment count per manufacturer/GPO. This goes beyond what the annotations alone provide.

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?

Three sentences with no filler: the first states what the tool returns, the second gives the output structure, and the third gives the intended 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?

For a simple tool with one optional parameter and no output schema, the description covers the necessary ground: what is aggregated, how it is grouped, what is returned, and when to use it. The schema handles the limit parameter, so nothing critical 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 description coverage is 100%, so the limit parameter is already fully documented. The description does not add parameter-specific semantics, but with full schema coverage a baseline of 3 is appropriate.

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 uses a specific verb and resource: it returns a pre-aggregated payment summary grouped by reporting company, with total dollars and payment count per manufacturer/GPO. The grouping dimension clearly distinguishes it from siblings like open_payments_by_specialty and open_payments_state_totals. The stated use case of ranking companies by pharma-influence spend adds further clarity.

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 tells the agent when to use this tool: to rank companies by pharma-influence spend. It does not mention alternatives or provide when-not-to-use guidance, so it stops short of a 5, but the context is clear enough for correct selection.

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