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

Beyond the annotations, the description explains the crucial behavioral nuance: this tool does not itself charge money, it returns a price and payment link, and the fax is sent only after the user deliberately pays. It also discloses that the underlying action is irreversible and real-world, matching destructiveHint and openWorldHint.

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 front-loaded with purpose, immediately follows with the cost and irreversibility warning, then clarifies the payment flow. It is appropriately sized for a money-related destructive action, and each sentence contributes to preventing accidental use.

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 lack of an output schema, the description sufficiently explains what is returned: authorization instructions, price, and a payment link. It also covers the key risks and prerequisites an agent needs before calling a destructive, open-world fax tool.

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%, so the single quote_id parameter is already fully documented by the schema as coming from quote_fax. The description reinforces that this is for a previously quoted fax but does not add format or validation details beyond what the schema provides.

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 states a specific verb and resource: it returns authorization instructions for sending a previously quoted fax. It also explicitly clarifies that the tool itself does not send the fax or charge money, distinguishing its real behavior from the potentially misleading name send_fax.

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 makes clear this is used after a fax has already been quoted, and the schema reinforces that quote_id comes from quote_fax. It does not explicitly name alternatives such as quote_fax, get_fax_status, or get_fax_receipt, but the prerequisite context is clear.

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