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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behaviour not in annotations: result ordering ("Newest first as Street orders them") and the pagination mechanism, though it omits the next_page contract used by the paging flow and says nothing about the embedded "included" payload produced by the include parameter.

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 tight sentences, front-loaded with the identity of the resource, then ordering and paging. The trailing "GET /lettings-applicants" is the only near-redundant element, though it is informative for API-oriented agents.

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 17-parameter, zero-required list endpoint with full schema coverage and no output schema, the description covers purpose, ordering and pagination adequately. The remaining gaps are modest: it does not mention the include parameter's effect on the response shape (the "included" array) or the trashed filter, which are the two parameters that most change what comes back.

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% across all 17 parameters, so the schema already explains page, page_size, include, trashed, date ranges and follow-up filters. The description's parenthetical echoes only a subset (budget, bedrooms, areas, furnished, lead rating) and adds no syntax or constraint detail, so it neither compensates for nor improves on 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?

States a specific verb and resource ("List lettings applicants") and clarifies what a lettings applicant is with the parenthetical "prospective tenants: budget, bedrooms, areas, furnished, lead rating", which makes it identifiable apart from the many other list_* tools. It does not explicitly differentiate itself from the nearest siblings street_get_lettings_applicant or street_list_interested_applicants, so it stops short of a 5.

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 implied rather than stated: the filtering parenthetical and the paging sentence tell an agent what this tool is good for, but there is no explicit "use this when" nor any named alternative such as street_list_interested_applicants or street_get_lettings_applicant for single-record retrieval.

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