get_deliverability_metrics

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

No annotations are provided, and the description does not disclose whether the tool is read-only, requires authentication, has rate limits, or any side effects. Although 'get' implies read-only, this is not explicit.

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 a single sentence that conveys the core purpose and key parameters without excess. It is concise but could be structured into a brief list for better readability.

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?

With no output schema and only 67% parameter description coverage, the description fails to explain return values, pagination, error handling, or behavior around metrics combinations. It is insufficient for a tool with six parameters.

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?

The description adds context that from and metrics are required and that group_by selects a breakdown dimension. However, it does not explain parameters like to, limit, or timezone, and the schema already documents group_by's enum values and meaning. The added value is marginal.

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 clearly states the tool gets deliverability metrics and highlights required parameters (from, metrics) and the optional group_by dimension. It distinguishes from sibling tools, which are about suppressions, templates, sending domains, etc., so there is no confusion with other metric tools.

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 like search_message_events or list_sending_domains. It does not mention prerequisites, when not to use, or how to choose breakdown dimensions.

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