create_contact

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

Annotations already show this is not read-only and not destructive; the description adds meaningful downstream behavioral context by warning that an invoice issued without `tax_id` will be rejected by Quipu. This is useful beyond the schema, though it doesn't describe return values or duplicate-contact behavior.

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 concise sentences front-load the action, then cover the required field and the conditional field. Every sentence earns its place, and there is 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?

The schema fully documents all 8 parameters, and the description covers the one significant conditional, `tax_id`, with a clear failure mode. The only notable omissions are an explicit pointer to update_contact for modifications and any indication of the response format, but these are minor for a simple create operation without an output schema.

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?

All 8 parameters are documented in the schema, so the baseline is 3. The description adds real value by explaining the `tax_id` requirement with concrete consequences and reinforcing that `name` is required. This goes beyond the schema's generic field description without needing to restate every parameter.

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 uses a specific verb and resource ('Create a contact in Quipu') and is clearly distinguishable from sibling tools like update_contact, delete_contact, list_contacts, and get_contact. It also immediately signals that `name` is required, removing ambiguity about the minimum valid invocation.

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 a clear decision rule: include `tax_id` whenever the contact will be invoiced, because Spanish invoices require it and Quipu will reject the invoice later without it. It doesn't explicitly name alternatives like update_contact for existing contacts, but the create action and thetax_id condition provide solid context for when this tool is appropriate.

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