Check if a phone number is opted out or suppressed, optionally scoped to a specific list.
Check whether a phone number is currently opted out / suppressed. Optional list_uuid scope.
| Name | Required | Description | Default |
|---|---|---|---|
| phone | Yes | Phone number to check | |
| list_uuid | No | Optional opt-out list UUID |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry the full burden of behavioral disclosure. It implies a read-only operation but does not explicitly state safety, authentication requirements, or the response format. The description adds little beyond what the name and schema already imply.
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 a single concise sentence that is front-loaded with the primary action and includes the optional scope. There is no filler or 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?
For a simple check tool with two parameters and no output schema, the description covers the purpose and optional scope but omits the response format or any behavioral details such as whether it checks global opt-out by default. Without annotations, more context on the return value would be helpful.
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 descriptions for both parameters. The description adds context that list_uuid is an optional scope, which clarifies its purpose beyond the schema's 'Optional opt-out list UUID' by indicating it scopes the check. This adds meaningful value.
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 action ('Check') and the resource ('whether a phone number is currently opted out / suppressed'), and mentions the optional list_uuid scope. This distinguishes it from sibling tools that manage opt-out lists or entries rather than check status.
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 is provided on when to use this tool versus alternatives such as list_opt_out_entries or create_opt_out_entry. The description implies usage but does not specify exclusions or recommend this tool over others for checking a single number.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.