List the phone numbers your account has proven it controls. Only these numbers (and Word Is Bond DIDs) may be used as a "pstn" targetAgent.toNumber. Revoke one with DELETE /api/numbers/{id}.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full transparency burden. It discloses the scope (numbers your account controls) and the constraint on PSTN target usage, but does not describe return structure, pagination, or other behavioral traits. It clearly implies a read operation but lacks explicit safety guarantees or side-effect disclosure.
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 valuable context about usage constraints. Every sentence earns its place, with 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?
The tool is simple with no output schema, so the description must explain the return value. It states it lists phone numbers and implies an ID via the DELETE reference, but does not explicitly describe response fields or format. This is a minor gap for a simple listing tool, hence a neutral score.
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 tool has zero parameters, so the schema is fully self-explanatory. The description adds no parameter details needed, and the baseline of 4 is appropriate since no parameter clarification is necessary.
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 verb 'List' and the resource 'phone numbers your account has proven it controls', making the purpose unambiguous. It also distinguishes from sibling verification tools by focusing on the list of confirmed numbers rather than the verification process.
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 clear context that these numbers (and Word Is Bond DIDs) are the only valid PSTN targets, implying when this tool should be used. It mentions revoking via DELETE but does not explicitly exclude alternatives or state when not to use this tool, though the usage context is strong.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools are clearly distinct by resource (monitors, suites, flows, numbers, recordings), but run_test and test_flow could be confused since both execute tests, though their scopes differ. The descriptions help disambiguate them.
All tool names follow a consistent verb_noun snake_case pattern (create_, get_, list_, run_, verify_, etc.), with no camelCase or mixed conventions. Even compound names like get_monitor_health and verify_number_confirm remain predictable.
At 16 tools, the set is slightly above the optimal 3-15 range, but the breadth of the voice-agent testing/monitoring domain justifies each tool's existence. It feels well-scoped rather than bloated.
The tool set lacks update/delete operations for most entities (monitors, suites, flows) and omits a get_run tool to retrieve individual live test results, leaving significant gaps that agents cannot work around. This will cause failures in lifecycle management and live-run result retrieval.
