buy_numbers

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses that real purchases are billable, that test=True avoids charges, that dry_run makes no write calls, that there is no undo except release_numbers, and that the return rows contain tpn_id. This is excellent transparency for a mutating, money-spending tool.

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?

The description is well-structured and front-loaded with the most critical warning and workflow requirement. The Args block is compact and each line adds value. The return-value note is brief and actionable. No sentence is wasted.

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 the tool's complexity, lack of annotations, and lack of output schema, the description is nearly complete: it covers purpose, mandatory dry-run workflow, cost, irreversibility, parameter semantics, and the next step. The only notable gaps are the undocumented account_id and token_name parameters, which prevent a perfect score.

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 0%, so the description must compensate. It adds meaningful semantics for phone_numbers, area_code, quantity, test, and dry_run, including the 1-500 range, the mode distinction, and the exact source for phone numbers. However, account_id and token_name are not explained at all, which is a noticeable gap given the schema provides only titles and defaults.

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?

The description opens with a specific verb and resource: 'Purchase CTM tracking numbers.' It clearly distinguishes this from sibling tools by positioning it as the purchasing step, and even references the downstream configure_numbers and the undo path release_numbers. The cost warning ('Real purchases cost money unless test=True') further clarifies the tool's real-world effect.

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?

The description gives explicit, actionable usage rules: ALWAYS call with dry_run=True first, show the user the plan, and get explicit confirmation before dry_run=False. It also explains the relationship to search_available_numbers and configure_numbers, and names release_numbers as the only undo path. This is model behavior for guiding an agent through a high-stakes workflow.

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