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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds real value beyond that by disclosing that associations are only populated when explicitly named in include, and by decoding the state enum values (0 Enquiry ... 3 Order) that would otherwise be opaque in output.

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 tight sentences plus an API-path reference, with the core fetch semantics front-loaded and no filler. Every clause carries information an agent needs.

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?

No output schema exists, so the description carries the return-value burden, and it does describe the main returned fields and the include-gated associations. It stops short of covering error behavior or default association omissions beyond the include note, but is largely sufficient for a single-resource read.

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 the baseline is 3, but the description goes further: it explains the behavioral consequence of the include parameter (associations are omitted unless named), which the schema's 'Associations to embed' phrasing only hints at, and it decodes the state field returned.

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 ('Fetch one opportunity') and immediately scopes it to a single record versus the sibling list_opportunities / list_opportunity_items tools. It also names exactly what is returned (dates, state, status, charge/cost totals).

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 implied — retrieve one opportunity by id — but the description never says when to prefer this over list_opportunities or when the include expansion is warranted. There are no explicit exclusions or alternative-routing statements.

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