direct_get_goal_statistics

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds genuinely new context beyond them: the 1-10 goal limit and the output column naming convention <Field>_<GoalId>_<Model>. It omits return-shape and pagination details, hence not a 5.

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?

Three tight clauses, front-loaded with the verb+resource and breakdown scope, then routing guidance, then the column-format hint. The only redundancy is 'Read-only', which repeats an annotation, but it costs almost nothing.

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 values need not be described, and the goal/model semantics are covered. However, for an 8-parameter tool with 0% schema coverage, the missing date-format, row_limit, report_type, and campaign_ids guidance leaves a real gap.

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 compensate and only partially does. It meaningfully explains goals (1-10) and attribution models, but leaves date_from/date_to format, row_limit, field_names, report_type, and campaign_ids undocumented.

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?

States a specific verb (get) and resource (goal statistics from Direct Reports) and scopes it to breakdowns by Metrika goals and attribution models. It explicitly distinguishes itself from the sibling direct_get_statistics, so an agent can select it without opening either schema.

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?

Gives an explicit when-to-use (CPA/ROI by goal) and names the alternative for the plain case (direct_get_statistics for cost/clicks). The selection condition is unambiguous rather than inferred.

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