signupgenius_add_group_member

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

The description explicitly states 'Writes data' and adds a confirmation requirement, which is behavior beyond the readOnlyHint: false annotation. It also clarifies that first/last names are optional. It doesn't mention behaviors like duplicate handling or errors, but the confirmation instruction adds meaningful transparency for a write operation.

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 sentences: the first states the action and optionality, the second provides the write/confirm warning. It is front-loaded, free of fluff, and 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?

For a write tool with no output schema and low schema parameter coverage, the description is adequate but leaves gaps. It covers the primary action and confirmation, but does not explain return values, error cases (e.g., duplicate email, invalid group), or idempotency. These would be valuable for an agent to invoke correctly and handle outcomes.

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 only 25% (only emailaddress has a description). The description compensates by explaining the core semantic: the member is added by email address, and first/last names are optional. This adds meaning beyond the schema, though it does not detail groupId beyond its name, which is self-explanatory in context.

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: 'Add a member to a SignUpGenius group by email address.' It specifies the resource (member/group), the method (email address), and optional parameters (first/last name). This distinguishes it from sibling read tools like list_group_members and get_group_member.

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: this is for adding members, and it explicitly warns 'Writes data — confirm with the user before invoking,' which serves as a usage guideline. It does not explicitly name alternatives or exclusions, but the action verb and resource make the intended use unambiguous relative to the read-only sibling tools.

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