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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the bar is lower, yet the description adds real value: identity documents and forwarding-address details are intentionally excluded from output, it reads current server state without manufacturing facts, and it is idempotent. The long 'confirmation boundary' sentence is generic boilerplate enumerating action types irrelevant to a read tool, which slightly dilutes the otherwise strong disclosure.

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 payload and usage guidance are front-loaded and useful, but the definition is bloated by a generic confirmation-boundary clause listing unrelated action types ('reversible save', 'plan refresh', etc.). Roughly a third of the text does not earn its place for a read tool.

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, the description correctly enumerates the returned fields and their exclusions, which is helpful. But it leaves both input parameters undocumented, so an agent cannot tell what _corply_context is for or whether companyId is required.

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% for two parameters, so the description must compensate and largely does not. It implies a single company via 'for one company', loosely mapping to companyId, but the nested _corply_context object (id/receipt) is completely unexplained in both schema and description.

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 names a precise read with a specific verb and enumerates the exact payload: entitlement, activation/identity state, assigned U.S. mailing address, open-item count, secure web URL, and nextStep for one company. This cleanly separates it from siblings like get_mail_item, list_mail, and start_corply_mail_activation, which handle individual items, listing, and activation respectively.

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 gives a clear when-to-use context ('mailbox readiness or address questions') and an explicit warning not to infer provisioning from a Corply Pay payment. However, it never names the alternative tools to call for activation (start_corply_mail_activation) or listing (list_mail), so routing is implied rather than spelled out.

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