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

Annotations already flag openWorldHint=true and idempotentHint=false; the description adds the non-obvious behavioral facts an operator cares about — no deduplication is performed and no notifications/e-mails are triggered ('Sends nothing'). It stops short of saying what a successful call returns (no output schema exists), so the agent cannot anticipate the created contact's identifier.

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 short sentences, front-loaded with the WRITE/count scope, then the duplicate caveat, then the notification caveat, then the underlying API. No filler and nothing buried.

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 9-parameter create with rich schema descriptions and no output schema, the description covers the two things the schema cannot: no duplicate check and no side-effect messaging. The remaining gap is type-dependent field requirements and the shape of the returned contact, neither of which is stated anywhere.

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 89%, so nearly every parameter is already documented in the schema, including the note that email/phone become the primary values. The description only restates that email and phone are optional, adding no format, conditional-requirement, or type-specific guidance (e.g. that Individual contacts generally need a last name).

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 and resource ('WRITE: creates ONE new contact') and lists the covered entity types (individual, organization, household) plus side-record creation. Naming the underlying APIv4 entities (Contact.create, Email.create, Phone.create) further pins down the exact operation and distinguishes it from civicrm_update_contact or civicrm_add_contact_to_group.

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?

Explicitly gives the when-not and the alternative: 'Does not check for duplicates: search first with civicrm_search_contacts.' An agent knows to call the search sibling before creating when duplicates are plausible, which is the main misuse risk for a create tool.

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