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

The readOnlyHint and openWorldHint=false annotations already establish that this is a safe, closed-corpus read, so the description's job is only to add context. It does contribute provenance signal ('source URL and verification date') and scope signal ('unmodelled costs', 'lock-in notes'), but most of the enumerated fields restate what the output schema already declares.

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?

One front-loaded sentence that names the resource and scope before enumerating payload contents. The field list is dense but every item signals scope rather than padding; a fragment structure is acceptable for a reference 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 an output schema and read-only annotations in place, the description only needs to convey scope and payload character, which it does. The one meaningful omission is how to obtain a valid vendor_id, which an agent calling a single-vendor lookup will need.

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?

There is a single required parameter at 0% schema description coverage, so the description must carry the load and it only implies that vendor_id is a single-vendor identifier via 'one vendor'. It does not say the expected format, whether it must come from list_vendors or search_directory, or what happens on an unknown id.

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 (returns structured pricing and capabilities) and a specific scope (one vendor), which separates it from list_vendors and compare_vendors at a glance. It stops short of naming those siblings explicitly, so the differentiation is implied by scope rather than stated.

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 only implied by the phrase 'for one vendor', which suggests this is the single-vendor lookup as opposed to the multi-vendor comparison siblings. There is no explicit when-to-use, when-to-use-instead (e.g. compare_vendors vs estimate_cost), or guidance on where the vendor_id comes from.

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