create_user_phone_numberCreates a new phone number for a specified user from provided data, allowing phone contact details to be added to Rootly users.
Creates a new user phone number from provided data
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | ||
| user_id | Yes | Required. ID of the user (fills `{user_id}` in /v1/users/{user_id}/phone_numbers). |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v2.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=true, so the mutation profile is known. The description adds nothing beyond that — it does not say what happens on duplicate phone numbers, whether the user must exist, or any auth/scope requirement.
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?
A single short sentence with no wasted preamble, but it is under-specified rather than concise — "from provided data" occupies space without conveying 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?
An output schema exists, so return values need not be described, but for a write tool with a nested payload the description omits everything an agent would want to know before calling: user existence, phone uniqueness, and the required request shape.
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 only 50%, and the uncovered portion (the nested `data`/`type`/`attributes` wrapper) is already fully structured in the schema. The description contributes no meaning to `user_id`, `phone` format, or the required JSON:API-shaped payload, so it fails to compensate for the low coverage.
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?
States a specific verb and resource ("Creates a new user phone number"), so an agent can tell it is a write counterpart to get_user_phone_numbers. However, "from provided data" is filler and no sibling differentiation (e.g., vs. create_user_email_address or the phone-number list tool) is offered.
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 when-to-use guidance, no prerequisites, no mention of the related read tool (get_user_phone_numbers) or of duplicate/rate-limit considerations. The agent must infer everything from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.