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

readOnlyHint=true already establishes this as a safe, non-mutating read, so the description's burden is lighter. It adds the fact that extra fields are opt-in and enumerates them, but says nothing about behavior on an invalid/unknown id, permissions required, or response shape. Adequate but not enriching.

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 compact sentences, front-loaded with the primary purpose and immediately followed by the optional behavior. The 'Elvanto: people/getInfo' endpoint reference is a compact, useful implementation anchor rather than filler.

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 two-parameter getter with full schema coverage and a readOnly annotation, this covers what an agent needs to call it correctly. The only gap is that no output schema exists and the description does not characterize the returned person object beyond the requested fields.

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 both parameters are fully documented in the schema, including the custom_<field id> convention and the cross-reference to elvanto_list_custom_fields. The description's field list largely restates the schema, so baseline 3 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 verb (Fetch), resource (one person), and access key (by id), with the optional expansion scoped explicitly. 'One person' cleanly separates it from elvanto_list_people and elvanto_search_people without needing to name them.

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: 'by id' signals that a known person id is the precondition, which implicitly routes the agent away from search/list tools. There is no explicit when-to-use statement and no named alternative (e.g. 'use elvanto_search_people if you only have a name').

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