Citable — AI share of voice across a competitive set

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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses meaningful behaviors: per-call pricing regardless of set size, no charge on failure, and the important semantic that share is of the compared set only. This adds practical context an agent needs for decision-making.

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 tightly packed sentences convey pricing, core function, output granularity, and key qualification, all without redundancy. The most decision-relevant facts are front-loaded, and every clause 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?

With no output schema, the description carries the return-value burden and does so well: mentions, AI search volume, share, and per-engine/per-language splits. It also covers input constraints, optional platform behavior, and pricing/failure terms, making it sufficient for safe invocation.

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 already covers both parameters well, but the description adds value by tying 'domains' to the 2–10 count and competitive-set comparison, and by noting 'per-engine splits', which clarifies the output effect of the optional platform parameter. It also clarifies that share interpretation depends on the set passed.

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?

Description uses a specific verb ('Compare') and resource ('AI-answer index'), and clearly enumerates outputs: mentions, AI search volume, and share of the compared set. It further differentiates itself from siblings by clarifying the share is relative to the requested set, not the whole index.

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 gives clear context for when to use the tool: to compare 2–10 domains in a competitive set. It does not explicitly name alternatives or exclusion criteria, but the 'compare' framing and share-of-set clarification make the intended usage unambiguous.

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