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

readOnlyHint=true already tells the agent this is a safe read, so the description only needs to supplement. It does add that certificate records carry type, expiry date and status, which hints at the shape of the result, but says nothing about what happens on a missing/invalid id or whether certificates can be expired-but-returned.

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 fragments with no waste, but neither is a complete sentence and the endpoint notation is developer-facing rather than agent-facing. Brevity here is trimming rather than economy: the same length spent on a verb+resource statement would be far more useful.

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?

The tool is simple (one param, no nesting, no output schema), so the burden is light. The description partly compensates for the missing output schema by naming returned fields, but it never states that it returns exactly one certificate, leaving a small gap.

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 coverage is 100% and the single `id` parameter is documented with its origin ('from the corresponding list tool'). The description adds no parameter meaning beyond the schema, which is the baseline expectation at full coverage.

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?

The fragment 'Property and unit certificates, type, expiry date and status' plus the endpoint 'GET /v2/certificates/{id}' implies a fetch-by-id operation, but there is no explicit verb and no statement that it returns a single certificate record. Sibling names (arthur_get_property, arthur_list_certificates) make the single-record read inferable, so the purpose is recoverable 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?

No guidance on when to call this instead of arthur_list_certificates, and no prerequisite stated beyond the schema note that the id comes from 'the corresponding list tool'. The agent must infer the list-then-get workflow without the description confirming it.

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