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

Annotations already mark the tool as mutating but not destructive (readOnlyHint=false, destructiveHint=false), and the description's 'Create' action is consistent with those flags. The description adds no additional behavioral details such as behavior on duplicates, required-field constraints, or response format, but it does not contradict the annotations.

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 tightly scoped sentences with no filler; the action is front-loaded and the purpose clause is a single useful addition. 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?

The description is minimal but adequate for a create tool whose full parameter semantics live in the schema and whose safety profile is covered by annotations. It does not mention that only first_name is required or what the call returns, but the schema carries the required-field information and no output schema was expected.

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?

The input schema documents all 13 parameters with descriptions, so schema description coverage is 100% and the baseline of 3 applies. The description names three business-relevant fields (birthday, relationship, contact_frequency_days), which slightly emphasizes which parameters matter, but adds no semantic detail beyond 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?

The description opens with the specific action 'Create a new contact', a clear verb-plus-resource pair with the CRM context. It does not explicitly differentiate from siblings like update_contact or list_contacts, though the verb makes the intended operation unambiguous.

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 implies the tool is for adding people to a personal CRM and highlights the tracking features (birthdays, relationship types, contact frequency reminders), suggesting when it should be used. It lacks explicit when-not-to-use guidance or routing to alternatives such as update_contact or list_contacts.

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