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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds valuable behavioral context beyond the annotations by clarifying the tool is scoped to the connected workspace and site and that callers should not pass a domain/site parameter.

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, each earning its place: the first lists what the tool returns, the second gives usage context and names the alternative, and the third resolves a likely parameter question. No filler or redundancy.

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 description covers the tool's multi-operation scope, the key decision of when to use it versus serp_competitors, and the scoping caveat about omitting domain/site parameters. With a full output schema, detailed parameter descriptions, and annotations, nothing essential for correct invocation 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 each parameter and action value is already documented. The description itself adds little parameter-level meaning, though it does clarify that no domain/site parameter is required, which is useful. Baseline 3 is appropriate because the schema carries the parameter semantics.

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 opens with a specific verb and object ('Research keyword demand') and enumerates the concrete outputs: search volume, difficulty, CPC, intent, keyword ideas, Trends interest, related queries, and Ads performance. It also explicitly distinguishes the tool from serp_competitors, so an agent can tell them apart immediately.

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 states exactly when to use this tool ('what to target and how much demand exists') and names the alternative for rankings ('who ranks today use serp_competitors'). It also gives a direct call instruction: no domain or site parameter is needed because it is already scoped.

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