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

The description adds the explicit confirmation requirement ('requires explicit confirmation') and reiterates destructiveness, which goes beyond the annotations that already declare destructiveHint=true. It also states 'Side effects: deletes contact group,' which is redundant but harmless. It provides useful behavioral context for the confirmation_text parameter.

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, front-loaded with the action and side effects. Every word adds value, and it is concise without being under-specified.

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 simple delete operation, the description covers the core purpose, side effects, and confirmation requirement. It does not detail error handling or return values, but the output schema exists and the tool is straightforward. The lack of explicit alternative guidance is a minor 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 input schema already describes both parameters (group_id and confirmation_text) with 100% coverage. The description does not add any extra meaning about the parameters themselves; it only mentions that confirmation is needed, which is already implied by the schema's description of confirmation_text. Baseline 3 is appropriate.

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 and resource: 'Delete a contact group (Fax.Plus tag).' It is specific and not a tautology. However, it does not differentiate from sibling tools like 'delete-contact' or 'delete-fax', so a slight deduction for lack of distinction.

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 notes that the action is destructive and requires explicit confirmation, which is a usage caution, but it does not specify when to use this tool versus alternatives or provide any context for when it is appropriate. No mention of alternatives or conditions.

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