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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds that requested relations land in an 'included' section and names the underlying endpoint, but says nothing about not-found behavior or 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?

Two short sentences, zero filler, and the core fact (single vendor by UUID) is front-loaded before the include caveat and the endpoint reference.

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 single-resource read with full schema coverage and readOnly annotations, this is nearly sufficient; the include-embedding behavior is surfaced. The only gap is that with no output schema, the caller gets no hint about the returned envelope beyond the word 'included'.

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% — both vendor_id (with a pointer to street_list_vendors) and the include enum are fully documented in the schema. The description only restates that include controls embedding, adding no format or nesting detail beyond that.

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 verb and resource ('One vendor by UUID') plus the include mechanism, which implicitly separates it from street_list_vendors. It never names the sibling or explicitly contrasts the two, so a reader must infer the singular-vs-list distinction.

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 'the related records you ask for in include' implies when include is relevant, but there is no explicit guidance on when to call this versus street_list_vendors, when to add includes versus making a second call, or any prerequisites beyond having an ID.

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