Send Message

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

The description adds an important behavioral instruction—'IMPORTANT: Always confirm with user before sending'—which is not captured in the annotations. This clarifies the required confirmation step. The annotations already mark readOnlyHint=false, so the write operation is expected, and the description complements this without contradiction.

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, front-loaded with the core action and a crucial warning. Every word earns its place, making it highly concise and well-structured.

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?

Given the tool's simplicity (3 params, no output schema), the description covers the essential action and the confirmation requirement. It omits potential failure modes or return values, but for a straightforward send operation, this is not a significant gap.

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 schema covers all three parameters with descriptions (100% coverage), so the description adds no additional parameter semantics. Baseline 3 is appropriate since the schema does the heavy lifting.

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 clearly states 'Send an iMessage or SMS' with a specific verb and resource. It distinguishes itself from siblings like send-email by specifying the messaging format (iMessage/SMS).

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 provides clear context (iMessage/SMS) but does not explicitly mention when to use this tool over alternatives like send-email. However, the medium is distinct enough to infer usage, and there are no exclusions or conditions provided.

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