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

With no annotations, the description carries the burden. It clearly states the always-on metric, the conditional weighted metric, and the interpretation caveat. It also explains the rationale for weighting (position 1 vs 9). It stops short of describing output structure or error cases, but the core behavior is transparent.

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 sentences, front-loaded with the main action, then conditional behavior, then an important limitation. Every sentence contributes meaning; no 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?

The tool has a moderate complexity with nested parameters and no output schema. The description covers the input semantics and the two possible metrics returned, and warns about the scope limitation. It doesn't detail the return format but that is not strictly required for a computation tool. It is reasonably complete for an agent to select and invoke correctly.

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?

Although schema coverage is 100%, the description adds meaning by explaining the function of the CTR curve and clarifying that entities can be per-keyword or pre-aggregated per competitor. It also explains when position is needed (when a CTR curve is supplied), which aligns with the schema.

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 the specific verb 'Compute' with the resource 'share of voice across competing entities over a keyword set', clearly distinguishing it from sibling tools focused on position weighting and click projection. It also specifies the exact metrics computed (impression share and optional weighted visibility share).

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 identifies a clear condition for using the weighted mode ('if you supply a CTR curve') and cautions that impression share is relative only to the supplied set. It does not explicitly name sibling tools as alternatives, but provides enough context to decide when to use the tool.

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