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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real value beyond that: it discloses the exact returned fields and the important limitation that shared negative keyword lists are out of scope. It does not mention pagination or result limits, which keeps it short of a 5.

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 tight sentences: scope first, returned fields second, usage trigger and exclusion last. Every clause carries information an agent would otherwise have to infer, and nothing is redundant.

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?

For a read-only, three-parameter listing tool with no output schema, the description compensates well by naming the returned fields and the out-of-scope shared lists. Combined with annotations covering the safety profile, an agent has everything needed to call it 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?

Schema description coverage is 100%, so campaignId, adGroupId and accountId are already fully documented, including the 'omit for the campaign's own negatives' rule. The description's note that ad groups are listed 'when adGroupId is given' largely restates the schema rather than adding new semantics, so the baseline of 3 is appropriate.

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 (list negative keywords), the two scopes (campaign vs. ad group via adGroupId), and the exact fields returned (id, text, match type). It also explicitly bounds scope by excluding shared negative keyword lists, so an agent can tell it apart from msads_get_keywords and msads_add_negative_keywords without opening the 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 concrete triggers for calling it — before adding more negatives, and when diagnosing a search term with no traffic — and names the sibling it pairs with (msads_add_negative_keywords). The exclusion of shared negative keyword lists prevents an agent from assuming coverage it does not have.

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