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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false. The description adds meaningful context beyond that: it returns live/current data, covers only existing campaigns, and explicitly does not return performance metrics. It does not contradict the annotations.

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?

The description is front-loaded and compact, with the core purpose stated first. The parenthetical about SB creation support is slightly verbose but earns its place by preventing misuse.

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 sparse input schema descriptions, the description usefully lists key returned fields and the non-performance scope. However, it leaves the filtering parameters undocumented, which is a notable gap for a list tool that supports filters.

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 only 25%, and the description does not explain the input parameters account_id, profile_id, state_filter, or campaign_id_filter. The field names it lists are output fields, not input filter semantics, so it does little to compensate for the schema gap.

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: listing the current state of existing Sponsored Brands campaigns. It distinguishes the tool from SB creation (not implemented) and from performance reporting (execute_sql), so an agent can identify its purpose without ambiguity.

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?

Explicitly routes performance questions (ACoS, spend, sales) to execute_sql on fact_campaign_daily, and clarifies that this tool does not create new SB campaigns. However, it does not explain when to use the state_filter or campaign_id_filter parameters.

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