Add Zero Contact

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

Annotations already signal a write operation with destructiveHint true and readOnlyHint false. The description adds meaningful behavioral context by noting the contact is created for the signed-in user and that explicit user consent is required, which goes beyond 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?

The description is a single, front-loaded sentence with no filler. It states the core action first and then the usage condition, making it easy to parse quickly.

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 simple two-parameter create operation with annotations covering the safety profile, the description is largely sufficient. It does not mention return values or duplicate behavior, but no output schema exists and this omission is not critical for basic invocation.

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 description provides no parameter-level guidance, and schema description coverage is 0%. The schema itself documents name and email with constraints, but the description does not compensate for the low coverage by explaining how the parameters should be supplied or what they represent beyond their names.

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 states a specific verb and resource: 'Add a contact for the signed-in user.' This clearly identifies the operation and scope, and distinguishes it from sibling tools like search_contacts and other read-oriented tools.

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 an explicit trigger: 'Call only after the user explicitly asks to save the contact.' This is a clear when-to-use and when-not-to-use statement, though it does not explicitly name alternative tools for related actions such as searching contacts.

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