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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral detail beyond annotations: the unified multi-platform scope, default account behavior when left empty, and the subtle Search Console behavior that rows are only ever returned by clicks unless a sort is specified. This meaningfully exceeds what annotations alone provide.

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 long but dense flame every sentence adds parametrical or behavioral value, and the primary purpose is front-loaded in the first sentence. The run-on semicolon style makes it slightly harder to parse, but the content is appropriately sized for an 8-parameter unified tool with cross-platform nuances.

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 tool with 8 parameters and an output schema, the description is complete enough: every operationally important parameter is explained, platform-specific nuances are disclosed, and the output is summarized as the platform's metric rows. The presence of an output schema means return-value details need not be spelled out, so no critical context 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 0%, so the description must carry the full parameter burden, and it does. It explains platform values, account ID semantics across platforms, days versus start_date/end_date, level values, breakdown dimensions, and the special Search Console combination/sort syntax. Only 'limit' is left to inference, which is reasonable since it is self-explanatory from 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?

The description uses a specific verb+resource ('report tool for EVERY connected platform') and explicitly scopes it to 'how did X perform' questions slash 'Returns the platform's metric rows.' It clearly differentiates from the sibling search/list tools by positioning itself as the unified reporting entry point rather than a platform-specific or metadata tool.

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?

The description gives explicit usage guidance: use for any performance question, pass platform/account/days/level/breakdown, and call describe(platform) to see supported options. It provides clear context and points to an alternative (describe) for discovering platform specifics, though it does not list explicit when-not-to-use cases or name a concrete sibling tool as the alternative.

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