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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value beyond that by disclosing the return contents ("including vendor and site names"), which matters because there is no output schema to convey the payload shape.

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 tight sentence with the resource and lookup key front-loaded and no filler. Every clause (single, by ID, return contents) contributes information.

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?

For a simple single-record getter with full annotation coverage, the description is largely complete, and it partially compensates for the absent output schema by naming what the response includes. It lacks only the routing guidance for locating the ID in the first place.

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% and the single id parameter is fully documented as a UUID, so the schema does the work. The description only restates that lookup is by ID and adds no format or constraint detail beyond the schema. Baseline 3 applies.

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 ("Get a single vendor site assignment") and scopes it to retrieval by ID, which distinguishes it from the sibling list_vendor_site_assignments. It stops short of naming that sibling explicitly, so the differentiation is implied rather than spelled out.

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 phrase "by ID" implies a prerequisite (you must already have an ID), but there is no explicit when-to-use guidance, no mention of list_vendor_site_assignments as the alternative for finding an ID, and no stated conditions or exclusions.

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