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

The readOnlyHint=true annotation already tells the agent this is a safe, non-mutating read. The description adds the useful scope detail that the full record (all fields) is returned, but does not disclose anything beyond that, such as error behavior for a missing id or pagination/format concerns.

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?

A single front-loaded sentence that opens with the resource and enumerates the returned fields, followed by the endpoint. No wasted words, though the raw 'GET /v1/relation/{id}' string is borderline implementation detail.

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 one-parameter read tool there is no output schema, so the description usefully enumerates the returned field groups, covering the main completeness need. It is largely sufficient against the annotations and full schema coverage, with only sibling-routing missing.

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% and the single id parameter is already documented as coming from eboekhouden_list_relations. The description adds no format or constraint meaning beyond what the schema provides, so the baseline 3 for high coverage applies.

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 ('One relation with all its fields') and enumerates what is returned (addresses, e-mail, VAT/KvK, IBAN, payment term, ledger), which is more than a tautology. It implicitly contrasts with the list_relations sibling by emphasizing a single relation, but never names any 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?

There is no explicit when-to-use or when-not-to-use guidance. The only routing hint ('from eboekhouden_list_relations') lives in the schema's parameter description, not the tool description, and it never distinguishes this from update_relation or get_member. Usage is only implied by the singular 'get by id' pattern.

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