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

Beyond the annotations, the description adds a crucial behavioral nuance: 'it never sends a message on the caller's behalf.' This prevents an agent from misusing the WhatsApp direct link by assuming the tool initiates contact. It also discloses the read-only nature in practical terms and describes what the response contains, adding real value over the raw 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?

Three sentences, front-loaded with purpose, then returns, then safety/no-arguments. The enumeration of channels is slightly detailed but earns its place because it sets agent expectations about the response. No wasted words.

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 zero-parameter, annotation-covered, read-only tool with an output schema, the description is fully sufficient. It covers purpose, content of the response, the behavioral caveat, and argument requirements. Nothing an agent needs to call it correctly is missing.

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?

With zero parameters, the schema has nothing to document and the description confirms this with 'No arguments.' Baseline 4 applies for a no-parameter tool; the explicit confirmation removes any doubt about optional arguments.

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 opens with a specific verb+resource ('tell a person how to contact Alexandre Caramaschi') and enumerates exactly what is returned (WhatsApp link, e-mail, form URL, CTA). This clearly distinguishes it from all siblings, which cover business info, courses, content, and location — none of which provide contact channels.

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 opening phrase 'Use to tell a person how to contact Alexandre Caramaschi' gives a clear trigger condition for when to invoke the tool. It does not name explicit exclusions or alternatives, but the sibling set is sufficiently distinct that the usage context is unambiguous.

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