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

The verb 'Read' and the word 'aggregates' communicate that this is a non-mutating summary operation, which is useful given that no annotations are provided. However, the description does not disclose what the response looks like, whether data is time-scoped, or whether the 'backlog' refers to messages, dead letters, or queue depth. It is transparent at a basic level but leaves meaningful behavioral details unstated.

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 with no wasted words. It front-loads the action and resource, and every word adds meaning. It is concise without being overly sparse to the point of tautology.

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?

Given that there is no output schema and no annotations, the description should more fully contextualize the return shape and the meaning of 'backlog'. The sibling list contains many deliverability-related tools, and without additional context an agent gets little help selecting among them. The tool has a simple parameter set, but the description is too terse to be fully actionable in a large tool namespace.

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 schema description coverage is 100% and the single parameter organization_id is described as 'Active organization ID', so the schema carries the parameter documentation burden. The tool description adds no additional parameter-level meaning beyond implying that the aggregates are organization-scoped. This meets the baseline for high schema coverage.

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 uses a specific verb ('Read') and names a concrete resource ('deliverability and backlog aggregates'). The word 'aggregates' helps distinguish this from event-level tools like commsharbor_delivery_events. However, it does not explicitly differentiate from other deliverability-related siblings such as commsharbor_delivery_get, commsharbor_domain_deliveries, or commsharbor_domain_report.

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?

There is no guidance on when to use this tool versus alternatives. The description implies usage when aggregate deliverability or backlog information is needed, but it does not state exclusions or point to sibling tools for more specific scenarios (e.g., per-domain reports, event logs).

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