Send message to phone

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

Annotations set destructiveHint and openWorldHint. Description adds behavior: temporary contact creation and deletion (contact_was_new/contact_removed), which aligns with annotations and provides useful transparency beyond the hints.

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 sentences with front-loaded action, no filler, and a link to detailed docs. 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?

With 8 params, output schema, and annotations, description covers core behavior and return values. Relies on external documentation for comprehensive details, but is sufficient for standard use.

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 baseline is 3. Description does not add new param info beyond schema; it mentions return values but not parameter meanings. No additional semantic value.

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?

Description clearly states the tool sends to a phone number, may create a temporary contact, and sends text or files. It distinguishes from sibling 'send_message' by focusing on phone numbers rather than chat IDs.

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?

Description gives clear context (sending to phone, temporary contact creation) but does not explicitly exclude alternatives or mention when not to use. It includes a link to full documentation for more details.

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