hail

Official

by hail-hq

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Python

Hybrid

List numbers

list_numbers

Read-onlyIdempotent

Retrieve a workspace's dedicated phone numbers, newest first, and paginate through results with limit and cursor parameters.

Instructions

List the workspace's dedicated phone numbers, newest first.

    ``limit`` is 1..200 (default 50). Pass the returned ``next_cursor``
    as ``cursor`` for the next page.

    Returns ``{"items": [{"id", "e164", "country_code",
    "number_type", "capabilities", "provisioning_state", "voice_agent_id",
    "sms_agent_id", ...}], "next_cursor"}``, or ``{"error": "<message>"}``.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_numbers"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No
`cursor`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.29.0Oct 21, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the description needn't restate safety. It adds real context beyond that: default ordering (newest first), the 1..200 limit bound with default 50, cursor-based pagination, and the error return shape.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the purpose, then pagination rules, then return shape — easy to scan and free of filler. The detailed return-value block is somewhat redundant given an output schema exists, costing a little tightness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a two-parameter read listing, everything needed to invoke it correctly is present: scope, ordering, pagination loop, and error behavior. The only excess is restating the response object that the output schema already defines.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden and does: it gives the limit range (1..200, default 50) and explains that cursor takes the previously returned next_cursor. Both parameters are fully operable from the prose alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource ('List the workspace's dedicated phone numbers') and adds a meaningful scope/ordering detail ('newest first'). It implicitly distinguishes from siblings like list_number_regions or quote_numbers by saying 'dedicated' numbers, but never names an alternative explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: an agent infers this lists provisioned numbers in the workspace. There is no explicit 'use this when…' or exclusion such as 'for a single number use get_number, for purchasable numbers use quote_numbers', even though the sibling list is crowded with number-related tools.

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