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

No annotations are provided, so the description carries the full burden of behavioral disclosure, and it discloses nothing: not that the call is read-only, not the result shape, not pagination limits beyond what the schema happens to say, not ordering. For an eight-parameter list tool with zero annotation coverage this is a complete gap.

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?

One well-formed, front-loaded sentence with no padding or filler, so nothing needs trimming. It is, however, too thin to be considered appropriately sized for an eight-parameter search tool, so it earns only the middle score.

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 annotations, no output schema, and eight parameters, the description would need to cover return shape and pagination behavior; it covers neither. The only saving grace is that the operation is an obvious low-risk read implied by the name, keeping this from a 1.

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 the schema itself is unusually informative (the "issued" alias semantics, comma-separated state values, partial-match on client_name, per_page max). The description adds nothing beyond it, so the 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?

The description "Search for proforma invoices" is a near-verbatim restatement of the tool name, adding only the word "for". It gives no indication of what distinguishes it from search_invoices, search_supplier_proforma_invoices, or get_invoice, so the sibling differentiation burden falls entirely on the name.

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?

There is no when-to-use guidance, no exclusions, and no named alternative. An agent must infer from the names alone that this is the customer-side proforma search while search_supplier_proforma_invoices covers supplier documents, and nothing states whether pagination or a filter is required.

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