List SCAN forms

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine context beyond that: it explains what a SCAN Form is (carrier scans all packages at once) and enumerates what is returned per address — labels_available, ship date, label count, PDF link. It omits pagination/result-size behavior, which matters given openWorldHint.

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?

Front-loaded with the core purpose, then supporting detail, then the sibling pointer. Every sentence carries information, though the 'A SCAN Form lets the carrier scan all packages at once' explainer is domain background rather than invocation guidance and slightly dilutes the front-loading.

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 parameters and no output schema, the description must convey the return shape, and it does: per-address counts plus a list of forms with ship date, label count and PDF link. The main remaining gap is volume/pagination behavior for an open-world read, which an agent cannot infer.

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 tool takes zero parameters, so the baseline of 4 applies. The description correctly implies no filtering input is required — it returns a breakdown across all Ship From Addresses.

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 ('List ... USPS SCAN Forms') and scopes it clearly: forms are grouped per Ship From Address, each with PDF links, plus a count of labels that still lack a form. This is distinguishable from the sibling create_scan_form and from list_ship_from_addresses/list_return_labels at a glance.

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?

Explicitly routes the agent to the alternative: 'Make one with create_scan_form.' That names the sibling and the condition that selects it. It stops short of stating when-not-to-use (e.g., no labels available, or when you only need shipments), so it is clear but not fully exclusive.

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