reach_createANewContactSegmentV1

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

With no annotations provided, the description carries the full burden. It discloses the deprecation status, the fallback to the default profile, and the inability to create segments in other profiles. These are meaningful behavioral details beyond the schema. However, it does not mention response behavior, idempotency, or authentication, so it is not fully transparent.

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 well-structured and front-loaded with the core action. The first sentence is a concise summary, but the second sentence repeats much of the same information, creating minor redundancy. The deprecation note is clear and purposeful. Overall, it is appropriately sized without unnecessary fluff.

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?

The description covers the main purpose, the criteria configuration, and the crucial deprecation limitation with a direct alternative. There is no output schema and no annotations, so the description could be expected to explain return values or error scenarios, but the deprecation warning reduces the need for full detail. It is reasonably complete for a deprecated 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. The description adds a high-level hint that segments can be configured with 'criteria like email, name, subscription status', which relates to the attribute enum, but it does not explain the `conditions` structure or `logic` parameter beyond what the schema already provides. The generic schema descriptions ('name parameter', 'logic parameter') are not enhanced substantially.

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 opens with 'Create a new contact segment' and expands on the purpose: organizing contacts with configurable criteria. It clearly distinguishes itself from the sibling tool `reach_createAProfileSegmentV1` by explicitly noting it is deprecated and cannot target a profile, which differentiates its scope.

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 explicit usage guidance: it states the endpoint is deprecated, cannot target a profile, and falls back to the client's default profile. It also gives a direct alternative: `POST /api/reach/v1/profiles/{profileUuid}/segmentation/segments`. This clearly explains when not to use the tool and what to use instead.

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