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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds real value by disclosing that results are permission-filtered (vendor clients see only their own vendor), which an agent cannot infer from the schema. It stops short of describing ordering, default page size, or result shape, but the access-scoping disclosure is a meaningful behavioral detail.

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 short sentences plus an endpoint reference, front-loaded with the action and resource. Nothing is redundant and the parenthetical definition earns its place by clarifying an ambiguous domain term.

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 parameterless-required, read-only list tool with full schema coverage and annotation-declared safety, the description covers purpose, scope, and access semantics. Minor omissions such as pagination defaults or result ordering are tolerable given the schema already documents all five parameters.

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 limit, match, accept, fields, and offset all documented inline, so the baseline is 3. The description adds no additional meaning about filtering, paging interaction, or whether 'accept' behaves as an ID allowlist applied post-scoping, leaving all parameter semantics to the schema.

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?

Specific verb 'List' plus resource 'vendors', with an inline definition of what a vendor is (bookingkit customers: tour/activity/attraction providers) and the exact API endpoint. The visibility rule ('A vendor client sees only its own vendor') further distinguishes it from bookingkit_get_vendor, which retrieves a single vendor.

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 makes clear this is the collection-listing operation and notes that results are scoped by client type, which implicitly tells an agent when it is appropriate. However, it never explicitly routes the agent: it does not say to use bookingkit_get_vendor when a specific vendor ID is known instead of listing, nor does it mention pagination expectations for large result sets.

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