get_user_phone_numbersRetrieves all phone numbers for a specified user by user ID, helping you look up contact numbers from Rootly.
Retrieves all phone numbers for the specified user
| Name | Required | Description | Default |
|---|---|---|---|
| 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=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered without the description. The description adds only the word 'all,' hinting at an unfiltered full listing, but says nothing about auth requirements, result ordering, or what happens when the user has no numbers.
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 front-loaded sentence with no filler, hedging, or redundant restatement of the title. Every word carries information about the operation and its scope.
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?
With an output schema present to explain return values and annotations covering safety, a one-parameter read tool needs little more than this. The remaining gap is minor: nothing about the user not existing or about the relationship between this tool and create_user_phone_number.
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 description coverage is 100% and the single user_id parameter is fully documented in-schema, including its path-template role. The description's 'specified user' merely restates the schema rather than adding format, validation, or sourcing guidance (e.g., where to obtain the user ID).
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 (retrieves) and resource (phone numbers) scoped to a single user, so the operation is unambiguous. It does not explicitly contrast with nearby siblings such as get_user_email_addresses or create_user_phone_number, relying on the tool name for that distinction.
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?
Usage is only implied: an agent infers 'call this when you need a user's phone numbers.' There is no statement of when not to use it, no mention of pagination limits, and no pointer to alternatives like get_user or list_users for broader profile data.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.