List all contacts with optional filtering by subscription status and tag. Supports pagination.
| Name | Required | Description | Default |
|---|---|---|---|
| page | No | Page number | |
| tagId | No | Filter by tag ID | |
| apiKey | No | Send16 API key (overrides SEND16_API_KEY env var) | |
| pageSize | No | Results per page (max 100) | |
| subscribed | No | Filter by subscription status |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It discloses pagination support and the ability to filter, implying a read-only operation. However, it does not explicitly state if it is destructive or what return format to expect.
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 extremely concise with two sentences, front-loading the main purpose and then adding key features. No extraneous information or repetition.
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?
Considering there is no output schema and no annotations, the description covers basic functionality but lacks details on authentication (apiKey), default ordering, and return format. Additionally, it does not clarify when to use this tool over siblings like search_contacts.
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%, so baseline is 3. The description adds value by grouping parameters into functional categories ('filtering by subscription status and tag' maps to subscribed and tagId; 'pagination' maps to page and pageSize). This enhances understanding beyond the schema alone.
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 lists all contacts with optional filtering, which directly indicates the verb and resource. It distinguishes from siblings like search_contacts by focusing on listing all with simple filters.
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 optional filtering and pagination but does not provide explicit guidance on when to use this tool versus alternatives such as search_contacts. No exclusion criteria or context for when not to use it is given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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