whatsapp_create_contact

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

Annotations already declare a non-destructive, idempotent, open-world write, and the description adds genuine value beyond them: it discloses the upsert semantics (a name update when the contact exists, consistent with idempotentHint) and bounds the blast radius to this account's address book. It does not cover auth requirements or what happens to the optional firstName on update.

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 tight sentences with zero waste; the core action and its upsert nature are front-loaded, followed by scope and return confirmation.

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 three-parameter mutation tool with no output schema, the description covers the essential what, scope, and return signal ('success confirmation'), and annotations carry the safety profile. Only minor gaps remain, such as behavior of the optional firstName on an existing contact.

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% and every parameter (id, fullName, firstName) is documented in the schema, so the baseline is 3. The description adds no parameter syntax, format, or required/optional detail beyond what the schema already states.

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 (save a contact) plus the upsert behavior (updates the name if it already exists), so the agent knows this is a create-or-update operation. It does not explicitly distinguish itself from the similarly named sibling whatsapp_send_contact, which also involves contacts, so differentiation is left to inference.

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 scope note 'Only affects this account's address book' implies the context of use and reassures the agent this is a local address-book write rather than a message send. However, there is no explicit when-to-use versus when-not-to-use guidance and no named alternative, so usage is only implied.

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