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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuinely useful behavior beyond that: the include-gated association loading and the meaning of the state codes (0 Enquiry, 1 Draft, 2 Quotation, 3 Order), which the agent would otherwise have to guess.

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 with the core retrieval facts front-loaded and the include caveat immediately after. No filler and the API mapping is appended compactly.

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 description carries the return-shape burden and does so by naming the returned fields and the association-inclusion rule. Nothing an agent needs to call this correctly is missing.

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. The description nonetheless adds meaning beyond the schema by explaining that associations such as customer, venue, line items, assets, and participants are only present when explicitly named in include, clarifying the effect of the include 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?

States a specific verb (Fetch) and resource (one opportunity) and enumerates the fields returned (dates, state, status, charge/cost totals). This clearly distinguishes it from list_opportunities and the update/create siblings in the same namespace.

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 sentence about associations only being returned when named in include gives concrete guidance on how to call it for a fuller payload. It implies single-record retrieval vs. the list sibling but never names list_opportunities as the alternative, so there is no explicit when-not routing.

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