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

Annotations already indicate a mutation (create). The description adds no further behavioral details beyond the creation action and segment type distinction. It does not disclose side effects, permissions, or idempotency considerations.

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?

Two sentences, front-loaded with the action and immediately providing key decision criteria. No redundant information.

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?

Despite an output schema and full parameter descriptions, the description lacks guidance on how to structure the criteria object for dynamic segments and does not mention that members must be set separately for static segments. The tool's complexity (nested object, multiple condition types) warrants more 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 parameter descriptions. The description adds value by explaining the semantics of segmentType (STATIC vs DYNAMIC), which goes beyond the schema's enum description.

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 tool creates a new customer segment and immediately distinguishes between STATIC (manual lists) and DYNAMIC (criteria-based auto-filtering), which differentiates from siblings like update_segment or set_segment_members.

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 guidance on when to use STATIC vs DYNAMIC segment types, but lacks explicit direction on when to prefer create_segment over update_segment or set_segment_members, and does not mention prerequisites or post-creation steps.

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