provision_phone_number

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

Discloses credit deduction and optional auto-selection of phone number. No annotations provided, so description carries the behavioral burden. Lacks details on failure modes or rate limits, but core behavior is covered.

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?

Three clear sentences plus a brief argument list. Front-loaded with purpose and critical behavior (credit deduction). 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?

Given no annotations but an output schema (not shown), the description covers prerequisites, parameters, and credit usage. Adequate for a provisioning tool; could mention idempotency or post-purchase steps.

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 0%, but description explains all three parameters: phone_number with E.164 example and auto-selection, type with default and options, friendly_name as optional label. Adds significant meaning beyond schema.

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?

Description clearly states it purchases/provisions a phone number for SMS, with specific verb and resource. Differentiates from siblings like list_available_phone_numbers (browse) and release_phone_number (release), as seen in the sibling list.

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?

Explicitly advises to use list_available_phone_numbers first to browse options. Provides context for when to use, but does not explicitly state when not to use. Still clear enough.

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