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

With no annotations, the description carries the full disclosure burden and does so well: it states the auth requirement (Authorization: Bearer), a metering constraint (pages metered per key per day), and the fallback behavior when no key is supplied (the response explains how to obtain one). It omits anything about rate-limit consequences or partial/error responses, so not a full 5.

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 tight sentences with the core purpose front-loaded and operational constraints appended; no filler. Slightly dense but every clause carries information (scope, page size, auth, metering, no-key behavior).

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 2-parameter export tool with no output schema, the description covers the key operational facts an agent needs: what it returns (every entity, with provenance), pagination shape, and auth/metering. The remaining gap is the exact page/response structure, which the absence of an output schema leaves slightly under-specified.

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 0%, so the description must compensate. It adds real meaning for pageSize ('200 a page', matching the maximum=200) and implies pagination via 'in pages', but says nothing about the semantics of the page parameter (e.g., 1-based, ordering, bounds), leaving one of two parameters undocumented.

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 action and resource: exporting every entity of the Immigration Adviser Finder register, in pages of 200, with provenance. An agent can distinguish 'whole register' bulk export from the search/lookup siblings like entities_search and entity_lookup. It stops short of naming an alternative explicitly, so it is clear but not sibling-differentiating.

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 by 'the whole register' — reach for this when you need everything rather than a filtered subset. However, no alternative is named and no explicit when-not condition is given, leaving the agent to infer that entities_search/entities_in handle targeted retrieval.

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