Create a new contact

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

The description discloses a meaningful behavioral trait beyond the annotations: when double opt-in is enabled, the contact is created with pending status and a confirmation email is sent. This is useful and not available from the readOnlyHint/destructiveHint annotations. It does not cover response shape or duplicate handling, but the disclosed behavior adds real value.

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 short and front-loaded with the core purpose. However, the second sentence restates the first ('Create a new contact' vs. 'This endpoint allows you to create a new contact'), which is mild redundancy. Overall it is still appropriately sized and easy to scan.

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 create operation with no output schema, the description omits what the endpoint returns or how success is indicated. It also does not address duplicate emails or other edge cases, and it does not help distinguish this tool from bulk/similar create siblings. The double opt-in behavior is helpful, but the description is not fully complete for an agent choosing and invoking the tool.

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 baseline is 3 even though the description does little parameter-level explanation. The description only mentions name, email, and surname as examples, and many schema descriptions are tautological ('name parameter'). The schema itself does provide meaningful info for phone format and tag_uuids, so the description does not need to compensate heavily.

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 action and resource: 'Create a new contact in the email marketing system.' It also gives a sense of scope with 'basic information like name, email, and surname.' However, it does not distinguish this singular create tool from the similarly named siblings reach_createNewContactsV1 and reach_createContactsInBulkV1.

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?

There is no explicit guidance about when to use this tool versus alternatives. The double opt-in note is behavioral context, not usage direction, and no exclusions or alternative tool names are mentioned. An agent must infer from the tool name that this is for a single contact creation rather than bulk creation.

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