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

Annotations already declare readOnly, idempotent, and closed-world, so safety is covered. The description adds real value beyond that: results are full provenanced vendor records, each plan carries source url + accessedAt, priced plans carry a dated citation meant to be quoted verbatim, and empty-query behavior is defined.

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?

Three sentences, front-loaded with the core purpose followed by scope and return behavior. Every sentence earns its place, though the field/citation detail makes it slightly dense for a search tool.

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 output schema, the description carries return-value burden and does so (provenanced records, citations, empty-query behavior). Combined with the safety annotations, an agent has everything needed to call this correctly.

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 50% — `section` is well documented in-schema but `query` has none. The description compensates by explaining what `query` matches (vendor name, domain, integrations, plan notes, capabilities) with examples, and by clarifying `section` is a theme slug sourced from list_sections. That fills the documented gap above the baseline.

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 (search) and resource (vendor data index) and names the searchable fields (vendor name, domain, integrations, plan notes, capabilities) with concrete example queries. It is clearly distinguishable from the sibling search_products, which targets products rather than vendor records.

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?

Explains that it works for every theme (hub sections and catalog topics alike) and tells the agent to set `section` to the theme slug from list_sections, plus that an empty query returns all vendors. It gives clear operating context but never explicitly contrasts when to prefer this over search_products or compare.

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