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

Annotations only supply destructiveHint=true, which says little about a create operation, so the description carries useful extra weight: it discloses that the call returns a new person id and family id and that no login is created — a non-obvious side effect. It still omits permission requirements, duplicate-person handling, and failure behavior, so it is not fully transparent.

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 short sentences, all front-loaded: purpose, return shape, and a key negative behavior. No filler, no repetition of schema content.

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 13-parameter mutation tool with no output schema, the description covers purpose, return values, and the no-login caveat well, and the schema fully documents parameters. It could still say more about authorization, duplicate detection, and family_id interactions, which are the main residual gaps.

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%, so the schema already explains all 13 parameters, including the fields object with its *_replace / *_remove variants and the access_permissions refusal. The description adds no parameter-level guidance of its own, so the baseline 3 is appropriate.

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+resource ('Add a new person to the church database'), gives a concrete use case (first-time guest), and disambiguates from siblings like elvanto_update_person and elvanto_add_person_to_group. It also names the underlying API endpoint (people/create), which pins the semantics precisely.

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?

The 'first-time guest' example implies a usage context, but there is no explicit when-to-use vs. when-not, and no mention of the natural alternatives (update_person for existing people, add_person_to_group / add_person_to_flow_step for post-creation placement). Preconditions such as required permissions or duplicate handling are left implicit.

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