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

With no annotations, the description carries the full burden and does it well: it discloses the hard cost (9 credits per call, independent of seed count), the absence of offset/paging and why, and the critical semantic that a full-length response is capped rather than complete. These are exactly the non-obvious traits an agent would otherwise have to discover by wasting credits.

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?

Front-loaded with the value proposition and cost, and nearly every sentence earns its place. The final two cap sentences overlap somewhat ('no offset or paging' vs. 'capped, not complete ... call again'), a mild redundancy in an otherwise efficient block.

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?

No output schema and no annotations, yet the description supplies the returned fields, the cost model, the cap/paging semantics, and the batching strategy. Nothing an agent needs to invoke this correctly and cheaply 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; the description adds real meaning by tying `limit` to billing and explaining that it is not a page-size parameter (no second page exists) and should instead be raised to the max. It also implies batching many seeds into `keywords` to amortize cost, though it doesn't restate country/language fallback behavior.

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?

States a specific resource (Bing's own related keywords for seed terms) plus the returned metrics (volume, competition, CPC), and explicitly distinguishes itself from the sibling Keyword_Ideas by noting Bing's different long-tail phrasing. An agent can route between the two without opening either 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?

Gives explicit when-to-use guidance ('run alongside Keyword_Ideas rather than instead of it'), a batching rule ('batch them into one call' since cost is fixed per call), and a paging rule ('raise the row count in a SINGLE call ... rather than calling again'). Both the alternative and the conditions selecting it are named.

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