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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the concrete endpoint (GET /invoices/{id}) and that include controls embedded records, but says nothing about not-found behavior or response size.

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, front-loaded with the resource and scope. The trailing 'GET /invoices/{id}' is largely redundant with the tool's purpose but is short enough not to hurt.

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 two-parameter read tool with full schema coverage, the description is adequate but not complete: with no output schema, it never says what the returned invoice record looks like or how embedded records appear in '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 coverage is 100%, so both the UUID format/source and the include enum are fully documented in the schema. The description merely restates that include embeds related records, adding no format or constraint detail beyond structured fields.

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 ('One invoice by UUID') and clarifies that related records come via include, which contrasts with the list siblings such as street_list_invoices. It stops short of naming any sibling explicitly, so it's clear but not maximally differentiating.

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?

Usage is only implied: 'One invoice by UUID' suggests single-record retrieval as opposed to listing. There is no explicit when-to-use/when-not or prerequisite guidance, though the schema does point to street_list_invoices as the source of the ID.

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