Create or update a contact profile

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

Beyond annotations (readOnlyHint=false, idempotentHint=false), the description discloses the critical full-overwrite behavior ('the API clears anything omitted'), the return value, and the scope of change (future orders only, not existing domains). This is exactly the kind of non-obvious behavioral trait an agent must know before invoking.

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 sentences, zero filler, with the main verb front-loaded and the most dangerous caveat (field clearing) immediately following it. Every sentence earns its place.

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 tool with an 18-field nested body, create/update branching, and a full-overwrite semantics, the description covers all the risky decision points and points to the read sibling for the update workflow. With an output schema present and no need to detail return values, it is nearly complete; it could optionally note whether creating a profile triggers contact validation, but nothing an agent needs to call it correctly is 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 coverage is 100%; the id parameter description already explains 'Omit it to create a new profile' and the body description already states the overwrite rule. The description adds the get_profile workflow hint, but otherwise repeats semantics the schema provides, so 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?

The description states a specific verb and resource: 'Creates a contact profile when id is omitted, or updates the profile with that id, and returns the saved profile.' It precisely defines the create/update branching and differentiates the tool from siblings like eurodns_contact_get_profile (read) and eurodns_contact_set_as_default_profile (role assignment).

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 description gives an explicit workflow directive — 'start from eurodns_contact_get_profile' — for the update path, and clarifies the effect scope ('Domains already registered keep their contacts; this changes what future orders use'). It doesn't explicitly name alternatives to avoid, but the create/update decision rule and the get-first workflow are clear enough for an agent.

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