Unassign a phone number from an agent while keeping it in your account. Use this to free a number for reassignment without losing ownership.
Detach a phone number from an agent. The number is kept in your account but becomes unassigned.
| Name | Required | Description | Default |
|---|---|---|---|
| agent_id | Yes | The agent ID that currently owns the number | |
| number_id | Yes | The phone number ID to detach |
Changes observed during successful MCP inspections.
v0.7.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotation idempotentHint=true already tells the agent that repeated detaches are safe. The description adds that the number is kept but becomes unassigned, which is useful (non-destructive in terms of data retention), but doesn't cover permissions, side effects on the agent, or what happens if the number is already detached.
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?
Two short sentences, front-loaded with the action and result. No wasted words, though it could be slightly more structured for usage guidelines.
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 mutation tool with full schema coverage and an idempotency annotation, the description covers the essential outcome. However, it lacks guidelines on when to use it and doesn't mention any side effects on the agent, leaving some gaps for an agent's decision-making.
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%, so the schema already fully documents both parameters. The description adds no additional parameter information, so baseline 3 is appropriate.
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 (detach) and resource (phone number), and clarifies the result. Clearly distinguishes from the sibling attach_number.
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 on when to use this tool versus alternatives. It doesn't mention prerequisites or when you might detach a number (e.g., before reassigning). The sibling attach_number is not referenced.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.