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 at a low bar. The description adds the metric list and account-level scope but discloses no further behavioral traits such as how aggregates are computed, profile-selection behavior with multiple tokens, or handling of date ranges with no data.

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?

A single 17-word sentence with the verb and scope front-loaded ahead of the metric enumeration. Every word carries information; there is no filler or repetition of the title.

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?

The metric enumeration partially substitutes for a missing output schema, and annotations cover safety. However, with 0 required parameters and three undocumented date/profile parameters, the description leaves ambiguity about the minimum viable call (are start/end dates required? what does period_days do?) that an agent must resolve elsewhere.

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% — only profile_id is documented in the schema, and its description already covers its semantics. The description's 'for a date range' loosely maps to start_date/end_date/period_days but does not explain their formats or relationship (e.g., whether period_days substitutes for start/end dates), so it fails to compensate for the three undocumented parameters.

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 opens with a specific verb ('Get') and resource ('account-level aggregate metrics for a date range') and enumerates the exact metrics returned: total spend, sales, ACoS, ROAS, clicks, impressions, purchases. The 'account-level aggregate' qualifier distinguishes it from sibling tools at campaign, ad group, keyword, and daily-trend granularity (ppc_campaigns, ppc_ad_groups, ppc_daily_trend).

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 provides no guidance on when to use this tool versus alternatives — it never names a sibling or states when NOT to use it. In a sibling set of ~70 PPC tools (ppc_campaign_details, ppc_daily_trend, ppc_period_comparison, ppc_query), an agent gets no routing help beyond the implicit 'account-level' hint.

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