create_contact

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It does add useful context such as required authentication scope and the minimum input validation rule. However, it does not describe the return value, error behavior, or what happens if the required conditions are not met.

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?

The description is two concise sentences, front-loaded with the primary action. Every sentence provides meaningful context (what it does, requirements, permissions) with no filler.

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 tool has several nested parameters, no output schema, and no annotations. The description leaves important gaps: it does not state what the tool returns (e.g., the created contact), how invalid input is handled, or the behavior when the addressBookId is omitted. The schema documents parameters well, but the description is incomplete for an agent to fully anticipate the tool's behavior.

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 description coverage is 100%, so the baseline is 3. The description adds a cross-field validation rule (name or at least one email) that is not captured in any single parameter's schema description, which is valuable and pushes the score above baseline.

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 clearly states the action ('Create'), the resource ('a new contact'), and the scope ('in the address book'). It is easily distinguished from sibling tools like update_contact, delete_contact, and list_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?

The description provides explicit prerequisites: a name or at least one email address, and an API token with read-write contacts scope. This gives clear context for when the tool should be used, though it does not explicitly contrast it with sibling tools or mention when not to use it.

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