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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so safety is covered. The description adds that the response is 'Full data, nothing trimmed' and includes prioritized insights with suggested actions, but it omits operational details such as response size caveats, auth requirements, or rate limits.

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 purpose is front-loaded, but the remainder is a dense run-on list of data categories rather than structured sections. Most listed items are relevant for a no-output-schema overview, but the single long sentence and trailing 'Full data, nothing trimmed' reduce scanability.

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?

Given annotations cover the operation profile and the schema fully documents the single optional parameter, the description's main job is to convey return scope. It does so by enumerating included ads metrics and insights, though it does not describe output organization or how brand-vs-rival comparisons are structured.

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?

There is one optional 'domains' parameter, and schema coverage is 100%; the schema already explains domain filtering and the default all tracked brands behavior. The description does not add any further meaning about the parameter, so the high-coverage baseline of 3 applies.

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 names a specific resource ('cross-channel ads picture') and enumerates its scope: live/new ads, reach, channel mix, 12-week launches, Google country matrix, Meta placement concentration. The 'cross-channel' and 'overview' framing implicitly separates it from single-channel siblings like get_google_ads_shopping_targeting_and_creatives and get_meta_ads_reach_messages_and_landing_pages, though it does not name them.

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?

No explicit when-to-use or when-not-to-use guidance is provided. It does not point to the detailed Google/Meta ad tools as alternatives or clarify whether this is for a first-pass overview versus deep dives, leaving routing to inference.

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