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

Annotations only supply destructiveHint and a title, so the description carries real weight here and delivers: company-name uniqueness constraint, implicit company creation, the extra GetUser call as a side-effect/cost of omitting assigned_to, and the return shape { ContactId } with no output schema present. It does not discuss permissions or duplicate-name failure 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?

Four sentences, front-loaded with purpose and scope, each carrying operational information. The trailing 'LACRM: CreateContact.' API tag is marginal filler, but everything else 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 12-parameter creation tool with nested objects and no output schema, the description covers the return value, the person/company fork, the uniqueness rule, and the default assignment. It leaves out what happens on a duplicate-company-name collision and doesn't flag the required 'name' field, both of which would complete the picture.

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%, so the baseline is 3, but the description adds genuine meaning beyond the schema: company_name's create-if-missing side effect and the extra API call cost of omitting assigned_to are not stated in the schema. custom_fields guidance is largely duplicated from the schema.

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?

Opens with a specific verb and resource ('Create a new contact (person) or company record') and explicitly covers the two modes the tool supports. An agent can immediately distinguish this from siblings like lacrm_edit_contact, lacrm_get_contact, and lacrm_search_contacts.

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?

Gives concrete conditional guidance: company_name applies only when creating a person, is_company switches record type, and omitting assigned_to triggers the API-key user default. It never names an alternative (e.g. lacrm_edit_contact for existing records), so no explicit when-not guidance, but the context is clear.

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