create_segment

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

Annotations already indicate non-idempotent (idempotentHint=false). The description adds a warning about flexibility and segment-builder compatibility, which is useful. However, it does not disclose return values, error scenarios, or side effects beyond duplicate creation.

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 relatively concise but includes some redundancy (e.g., 'Creates a new record' after 'Create a Segment'). The front-loaded emoji and endpoint are good, but the warning could be more succinct.

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 complex nested schema and lack of output schema, the description is insufficient. It does not explain what the response looks like, error handling, or required permissions. The warning about segment-builder is helpful but does not cover the missing context.

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% with detailed descriptions for all nested properties. The description adds a high-level caution about the data structure but does not enhance understanding of individual parameters beyond the schema. Baseline score 3 applies.

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 states it creates a Segment and includes the HTTP method and endpoint. It is clear that the tool creates a new segment resource, but it does not explicitly distinguish from other create tools like create_a_new_contact. However, the name and context make the purpose sufficiently clear.

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 mentions non-idempotency and warns that only segment-builder-supported configurations work, advising users to refer to the builder page. However, it does not specify when to use this tool over alternatives like update_segment or retrieve_a_segment, nor does it mention prerequisites or authorization.

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