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 the upstream endpoint, which is mildly useful context, but says nothing about pagination behavior, default page size, or default ordering — all of which matter for a 12-filter listing tool.

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, front-loaded with what is returned; no padding. The trailing 'ServiceTrade API: GET /invoice' is marginal but compact and gives the agent the upstream contract.

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 usefully names the fields returned, and the fully documented schema covers all 12 optional filters. The main omission is pagination/result-size behavior, which an agent needs to know for a large collection endpoint.

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 every filter, enum and timestamp unit is already documented in the schema. The description's field list ('status, customer, job, totals, due date and paid state') restates what the parameters cover rather than adding syntax or interaction detail, so 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?

Specific verb + resource ('List invoices') with the returned fields enumerated, and the underlying endpoint (GET /invoice) confirms it is a collection read. The 'list' vs. the sibling 'servicetrade_get_invoice' distinction is implied by the verb rather than stated, so it stops short of a 5.

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: the field list hints that this is for browsing/scanning invoices filtered by status, customer or job. There is no explicit guidance on when to prefer this over servicetrade_get_invoice for a single record, and no mention of paging through results.

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