list_packages

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds value by specifying the return fields (tracking number, carrier, status, received timestamp) and the scope of data (inbound mail/packages for specific accounts), which is beyond the annotations.

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 sentences: first covers action and filters, second covers return fields and alternative tool. No wasted words, front-loaded with key purpose.

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 the presence of an output schema and zero required parameters, the description is fairly complete. It covers purpose, filters, return fields, and alternative. Could mention pagination settings (limit/offset) but those are in schema.

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 100%, so baseline is 3. The description mentions optional filters by status, carrier, and date, but the schema already documents all parameters with descriptions. The description does not add significant new semantic meaning beyond the schema.

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 explicitly states 'List inbound mail or packages for approved real mailing address/package beta accounts with optional filters', providing a specific verb and resource. It distinguishes from sibling tool list_inbound_mail by mentioning the account type and alternative for general context.

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 clearly states when to use this tool ('for approved real mailing address/package beta accounts') and explicitly indicates when not to use it ('For generally available inbound postal context, use list_inbound_mail'), providing a direct alternative.

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