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

Annotations already declare readOnly, idempotent, closed-world behavior, so the description's main added value is the return payload: "names, countries, ids and endpoints." That is genuinely useful given there is no output schema. It does not discuss match behavior (exact vs partial) or empty-result handling, which keeps it below 5.

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 sentences, zero filler, with the action and scope front-loaded and the return shape second. Nothing repeats the schema or annotations.

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?

A simple read-only search with fully documented parameters and a stated return shape covers nearly everything an agent needs. Only minor gaps remain: result ordering/pagination semantics and what an empty match set looks like.

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 q, limit and country are fully documented in the schema, establishing the baseline of 3. The description adds only the marginal detail that q can target line of business, not just name; it says nothing about limit or country beyond what the schema already covers.

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?

"Search the register for a supplier (firm) by name or line of business" gives a specific verb (search), resource (supplier register) and match fields. It is clear enough to separate from lookup siblings like assay_supplier, though it never names them explicitly.

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 match fields (name or line of business) imply this is the discovery step before fetching a specific supplier via a sibling, but no when-to-use or when-not-to-use guidance is stated. The agent must infer the search-then-fetch workflow from the sibling names.

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