Create Contact

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

No annotations are provided, so the description carries full burden. It discloses the mutation behavior ('create') and optional features, but lacks details on idempotency, email validation, default behaviors, or response format. It is adequate but not thorough.

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 one sentence, front-loaded with the main action, and contains no filler. Every word is meaningful.

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 7 parameters (1 required), no annotations, and no output schema, the description covers the basic functionality but omits important context like expected return value, error conditions (e.g., duplicate email), and default behaviors. It is minimally complete.

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 coverage is 100%, so baseline is 3. The description adds minimal value beyond what the schema already provides, only implicitly grouping parameters like 'segments' and 'topics'. It does not enhance understanding of individual parameters significantly.

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 the verb 'create' and the resource 'contact in Resend', and distinguishes from sibling tools like 'update-contact' by adding optional capabilities (segments and topic subscriptions). It is specific and differentiates well.

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 implies the primary use case (creating a new contact) but does not explicitly state when not to use it or compare to alternatives like 'update-contact'. However, the context of sibling names and the phrase 'Optionally assign to segments' provides implicit guidance.

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