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

With readOnlyHint=true already declaring a safe read, the description adds genuine behavioral context: the mandatory-filter rule, the reason (no bulk listing), and the underlying POST /api/v1/getvendors endpoint. It stops short of describing ordering, pagination, or error behavior, but the annotation carries the safety profile.

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, both earning their place: the first defines filters and matching semantics, the second carries the guardrail and endpoint. The most important constraint is front-loaded and nothing is repeated from the schema.

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 read-only filtered search with six well-documented optional parameters, the description plus schema cover what an agent needs; the max_results total-count behavior is documented in the schema. No output schema exists, but the tool's return shape is simple enough that omitting it is acceptable.

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 per-parameter descriptions exist, but the schema declares zero required parameters while the description supplies the crucial anyOf-style constraint that at least one filter must be supplied. It also adds the matching-mode distinction (partial vs exact) that maps parameters to lookup intent.

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 names a specific verb (Search) and resource (vendors/suppliers) and enumerates the supported lookup keys with matching semantics (name partial, reg/VAT exact, id, changed_since). This clearly distinguishes it from sibling list tools like merit_list_customers and merit_list_items.

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?

It states a hard usage precondition — at least one filter is required because the whole vendor list cannot be returned — which tells the agent when the tool will not work. It does not, however, explicitly name a sibling alternative or cover the unfiltered-enumeration case beyond that.

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