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

No annotations are provided, so the description carries the full behavioral burden. It does strong work disclosing the 9-credit flat cost regardless of keyword count, the 200-keyword hard cut that silently drops the tail, and the absence of paging. It does not state auth/prerequisite requirements or the exact shape of returned rows beyond the four metric families, leaving some gaps. With no annotations to lean on, this robust but incomplete disclosure lands at the low end of adequate.

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-loads purpose, then cost, then the cap, then the no-paging fact. Dense but every clause carries information. The one weak sentence is 'Compare the rows returned against the keywords you sent,' which is an inferable admonition rather than a fact.

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 and no annotations, the description compensates by covering cost, the 200-row cap and truncation behavior, and the absence of paging. An agent can decide whether to call it, how to batch, and how to interpret a short return list without further information.

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 schema itself documents country/language/keywords, giving a baseline of 3. The description adds genuine operational meaning for the keywords parameter (batch all keywords into one call; the effect is identical whether you send 1 or 200), which is not in 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?

States a specific verb and resource: Bing search volume, competition, CPC, plus monthly history, for up to 200 keywords. It is clearly distinguishable from sibling Keyword_Metrics (non-Bing) and Bing_Keyword_Ideas (ideation vs. metrics) 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 conditions: when a site draws meaningful Bing traffic (verifiable via the named sibling Bing_Search_Performance), or when the audience skews Windows/Edge. Names the alternative tool and the signal that routes to it.

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