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

Annotations already declare readOnly, non-destructive and open-world behavior, so the safety profile is covered. The description adds return-content knowledge the annotations cannot: possible status values (sent / scheduled / canceled) and the credit-usage and per-channel failure figures. It omits nothing an agent needs before calling.

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 dense sentence plus an endpoint fragment, with the resource named first and the returned fields enumerated afterward. Every clause is informative, though the endpoint path is slightly redundant for an agent that only needs the tool call.

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?

For a read-only single-parameter tool with no output schema, the description compensates by enumerating the returned fields and status values. Safety and parameter origin are covered; only pagination or freshness behavior is left unstated, a minor 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?

Only one parameter exists and the schema documents it at 100% coverage with the pattern and origin ('Message id returned by trumpia_send_message'). The description restates that origin but adds no format or syntax beyond the schema, so the baseline 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?

States a specific verb and resource (delivery statistics of a message), and enumerates the exact payload: status, totals, sent/failed counts per channel, credits used. It even cites the endpoint GET /message/{message_id}, letting an agent differentiate it from siblings like trumpia_get_request_report or trumpia_list_scheduled_messages.

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 phrase 'of a message sent with trumpia_send_message' establishes the precondition and the source of the required message_id, which is meaningful routing context. It does not, however, state exclusions or name an alternative to use when this tool is the wrong choice.

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