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

With no annotations, the description carries the full burden and does a good job: it states that only active vendors are returned, lists the returned attributes (Peptul Score, verified-COA status, country), and discloses the ordering ('scored vendors first'). It does not mention potential rate limits, error behavior, or whether query matching is exact or partial, but the key behavioral traits are disclosed.

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?

The description is two short, purposeful sentences: the first identifies the tool and its scope, the second enumerates the return contents and ordering. No filler or redundancy; it is appropriately sized for the tool's simplicity.

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 simple search tool with no output schema and no annotations, the description adequately explains what is returned and in what order. Minor gaps remain around matching behavior (e.g., substring vs exact match) and the meaning of 'Peptul Score', but the core information an agent needs to call the tool correctly is present.

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%, with both 'limit' and 'query' already described (default and filter semantics). The description adds no additional parameter-level nuance beyond what the schema provides, so the baseline of 3 is appropriate.

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 clearly states the action ('Search') and the specific resource ('Peptul's open research peptide vendor directory'), and describes the output fields returned. It implicitly differentiates from siblings like get_vendor by focusing on directory search, but does not explicitly name the sibling or contrast them.

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 description implies usage: use this tool to search the vendor directory or list top vendors when omitting the query. However, it provides no explicit guidance on when to choose search_vendors over get_vendor, nor any exclusion criteria or alternative routing.

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