reach_listSegmentContactsV1

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

With no annotations provided, the description fully discloses the critical behavioral trait: the endpoint is deprecated, cannot target a profile, and falls back to the default profile. It also notes that it cannot read segments of any other profile, which is important context. It does not cover output format, but the most impactful caveat is transparently stated.

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 short paragraphs, starting with a clear purpose statement followed by essential deprecation context. Each sentence adds value—there is no filler or redundancy. The structure is front-loaded and easy to scan.

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 tool is a simple list endpoint with pagination parameters, and the schema covers parameter semantics. The description provides the crucial deprecation warning and directs users to the correct replacement. While it doesn't describe the response format, the tool's purpose of retrieving contacts is clear, making it adequate.

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 provides descriptions for all three parameters (100% coverage), so the tool description doesn't need to add much. It only reinforces that the segment is identified by UUID, which the schema already implies. No additional parameter semantics are provided, so the baseline score of 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 opens with 'Retrieve contacts associated with a specific segment,' clearly stating the action and resource. It explicitly identifies the segment by UUID and distinguishes this deprecated tool from the recommended alternative endpoint, making the purpose unambiguous.

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 explicitly labels the tool as 'Deprecated' and explains the key limitation: it 'cannot target a profile' and 'always falls back to the client's default profile.' It provides a direct replacement endpoint, giving clear when-to-use versus when-not-to-use guidance.

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