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

The annotation readOnlyHint=true already establishes safety; the description adds useful behavioral context about the active Space scoping and the ability to override it. However, it does not explain the return format or pagination behavior, so it does not fully disclose all behavioral traits.

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 three concise sentences with the primary function front-loaded, followed by filter usage and scope details. Every sentence adds value and there is no redundant wording.

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 report tool with no output schema, the description covers purpose, filters, and scope, and points to the OpenAPI spec for further details. It is sufficient for an agent to invoke correctly, though a brief note on response structure would have made it more complete.

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?

Although the schema covers space_id with a description, the description goes further by naming additional query-param filters (period, platformId, dates) that can be passed as keyword arguments, which is especially valuable because additionalProperties=true and these filters are not in the schema. This adds meaning beyond the structured 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?

The description clearly states the tool returns a 'value-aware conversion report' with specific metrics (conversions, conversion value, ROAS) and the purpose of verifying Target ROAS bidding. This distinguishes it from other report/stat tools like get_performance_stats by focusing on conversion value and ROAS.

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 provides clear context for when to use the tool ('so bidding toward Target ROAS can be verified') and describes scope handling via set_active_space or space_id override. It does not explicitly name alternative tools or exclusions, but the guidance is sufficient for basic selection.

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