Get package

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

Annotations already establish readOnly/idempotent safety, and the description adds substantial context: null means unlimited, quota_unlimited flags unlimited disk quota, the 403 refusal mode for non-reseller accounts, and an environment-variable precondition. That is real behavioral disclosure beyond the structured fields.

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?

Two dense sentences, front-loaded with the return payload before the qualifiers, and every clause carries information (null semantics, environment precondition). No filler or restatement of the title.

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 takes on the job of describing the return shape and does so field-by-field, plus null/unlimited semantics and the failure mode. An agent has everything needed to call it and interpret the result.

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 (name) and schema description coverage is 100%, with the pattern documented inline, so the schema fully carries parameter semantics. The description adds no naming, format, or resolution detail beyond it, which matches the baseline of 3 when the schema does the heavy lifting.

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 ('Returns a package's limits') and enumerates exactly what is returned: disk quota, domains, mailboxes, forwarders, domain pointers. This clearly distinguishes it from list_packages (enumeration) and get_quota (single-account quota).

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 explicit when-not conditions: reseller accounts only, regular accounts refused (typically 403), and unavailable while MXROUTE_USERNAME is in `reseller|user` form. It never names an alternative sibling (e.g., list_packages or get_quota) for the cases it excludes, keeping it just short of a 5.

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