get_sa360_campaign_performance

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: dates are inclusive, interpreted in the customer account's timezone, and costMicros must be divided by 1,000,000 into customer.currency_code — real value beyond the annotations, though pagination behavior is never mentioned.

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?

Four short lines, front-loaded with the returned metrics and followed by the operational constraints. No filler, though the opening is a bare metric list rather than a verb-led statement of what the tool does.

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?

An output schema exists, so return-value explanation is unnecessary, and annotations cover the safety profile. For an 8-parameter reporting tool the remaining gaps — pagination via page_token/page_size and what segment_by_date does to results — are meaningful omissions.

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% across 8 parameters, so the description must carry the load. It clarifies the date format/semantics and the cost_micros unit and hints at account hierarchy, but says nothing about page_size, page_token, segment_by_date (which changes result granularity), account, or login_customer_id.

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 first line names the exact metrics returned (impressions, clicks, cost_micros, conversions, conversion value) and the tool name supplies the campaign/SA360 resource and reporting verb, so the purpose is unmistakable. It also constrains the account type (advertiser/client, not aggregate manager), which separates it from generic query_sa360, though it never names that sibling explicitly.

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 states a clear usage condition: query an advertiser/client account rather than an aggregate manager for performance metrics. It does not say when to prefer this over query_sa360 or search_sa360_fields, so an agent gets a constraint but no explicit alternative routing.

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