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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds one genuinely useful behavior beyond that: results are 'ordered by visibility score', which tells the agent the default ranking. It says nothing about result caps, paging, or empty-result behavior.

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?

A single sentence with the resource, the required key, the optional filters, and the ordering behavior — front-loaded and with no filler. Nothing here is redundant or padded.

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?

For a 7-parameter read-only lookup with full schema documentation and clear annotations, the description covers what it must: scope, filters, and sort order. The remaining gaps (limit/lang behavior, result shape) are handled by the schema or are non-critical, and no output schema exists to lean on for returns.

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%, so every parameter is already documented with examples and enums. The description only names the optional filter categories, which the schema does better (e.g. any-of semantics for certifications, employee band examples). 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?

States a specific verb and resource ('List suppliers headquartered in a given country') plus the optional filter axes, so the agent knows exactly what set is returned. It does not differentiate itself from siblings like search_suppliers or find_suppliers_by_hs_code, which is the only thing keeping it from 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 implied by the country-keyed framing: use it when the geography is known. However, there is no explicit guidance on when to prefer this over search_suppliers, find_suppliers_by_hs_code, or match_suppliers_by_brief, and no stated prerequisites or exclusions.

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