List all dynamic segments, whose members are computed from a filter expression at send time.
List dynamic segments. Segments compute their members from a filter expression at send time.
| Name | Required | Description | Default |
|---|---|---|---|
| apiKey | No | Send16 API key (overrides SEND16_API_KEY env var) |
Changes observed during successful MCP inspections.
v0.5.7Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Absent annotations, description adds context that segments compute members from filter expression at send time, but does not disclose pagination, return format, or any side effects.
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 concise sentences, front-loaded with the core action. No wasted words.
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 list tool with no output schema, description should indicate scope (all segments?), return format, or any filtering. It lacks completeness.
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 covers 100% of the single parameter (apiKey) with full description. Description adds no additional meaning beyond schema.
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?
Description clearly states verb+resource: 'List dynamic segments'. It distinguishes from sibling list tools (e.g., list_audiences, list_contacts) by specifying 'dynamic' and briefly explaining the concept.
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?
No guidance on when to use this tool vs. alternatives like preview_segment or other list tools. No exclusions or context provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.