sendContact

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

With no annotations, the description carries the behavioral disclosure burden. It states the key action and the success return, but it does not mention preconditions, failure modes, permissions, or chat restrictions. This is acceptable for a straightforward send operation but leaves some behavioral gaps.

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 short sentences with no filler. The core action is front-loaded and the return behavior is stated efficiently. 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?

Despite rich input schema coverage, the description is minimal for a tool with 15 parameters, nested objects, no annotations, and no output schema. It lacks guidance on when to choose this over sibling send tools and provides no behavioral context beyond the basic action and success return. An agent would need to infer most usage context from the schema alone.

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 schema already documents all 15 parameters, including phone_number, first_name, and vcard. The description adds no parameter-level semantics, which matches the baseline expectation given full schema coverage.

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 ('Send') and a specific resource ('phone contacts'), which clearly distinguishes it from sibling send tools like sendMessage, sendPhoto, or sendVenue. It also adds the return behavior ('the sent Message is returned'), reinforcing what the tool accomplishes.

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 clearly indicates the tool is for sending phone contacts, which gives an agent enough context to select it over alternatives such as sendMessage or sendAudio. It does not explicitly list when-not-to-use or mention alternative tools, but the resource specificity provides solid implicit guidance.

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