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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered. The description adds genuinely useful return-scope context ('metadata only') but says nothing about pagination, ordering, or result limits for a list endpoint.

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, front-loaded with the purpose. The trailing 'Onfido API: GET /documents?applicant_id=…' restates what the tool name already conveys, so it is mild filler rather than a structural flaw.

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 simple single-parameter list tool with no output schema, the description covers purpose, scope, and return granularity ('metadata only'). Nothing essential to invoking it is missing, though return-shape detail is thin.

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 a single required parameter, so the schema already documents applicant_id fully. The description adds no syntax or format detail beyond what the schema provides, making 3 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 and resource ('List the identity documents uploaded for an applicant') and adds the scope qualifier 'metadata only'. It is distinguishable from the singular onfido_get_document by the verb, though it does not name that sibling explicitly.

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: you call it with an applicant_id to enumerate that applicant's documents. The '(metadata only)' note hints at when to prefer this over fetching a document's contents, but there is no explicit when/when-not guidance or named alternative.

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