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

Annotations already declare read-only/idempotent/non-destructive, so safety needs no restating; the description adds "Free" (no quota spend) and discloses the returned attribute set, which matters because there is no output schema. It stops short of stating pagination limits or what an unfiltered call returns (all suppliers' items vs. nothing).

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?

A single front-loaded sentence covering resource, fields and filtering, with the cost note as a terse tail. Nothing is wasted, though the standalone "Free." fragment is slightly clipped relative to the otherwise full sentence.

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 field enumeration usefully previews the shape of results, and annotations cover the safety profile. However, for a list tool with zero required parameters, the definition never explains the default behavior when neither filter is supplied or whether results are paginated or capped.

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 coverage is 50%: the supplier parameter is already documented as an id or name in the schema, while sku is bare. The description only restates that either can narrow the query, adding no match semantics (exact vs. partial, case sensitivity) or guidance on passing neither parameter.

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 states a specific resource (supplier items), enumerates the attributes returned (codes, costs, packs, minimums, lead times, preferred supplier), and bounds scope to "one supplier or one SKU." This clearly separates it from purchasing_list_suppliers (suppliers, not items) and purchasing_save_supplier_items (a write).

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?

"for one supplier or one SKU" implies how to narrow the result, and "Free" signals no credit cost, but nothing says when to choose this over purchasing_list_suppliers or purchasing_draft_reorders. There are no explicit exclusions or prerequisites, so the guidance is only implied.

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