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

With no annotations, the description carries the full behavioral burden. It discloses key consequences: invoices are charged on their due date or send date, failed charges are not retried, an email is sent, and the pay link remains available.

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 four sentences, front-loaded with the action, then the prerequisite, then billing mechanics, then failure behavior. Every sentence adds useful information without repetition.

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 two-parameter toggle with no annotations or output schema, the description covers purpose, prerequisite, billing timing, and failure handling well. It omits what happens to existing scheduled charges when auto-pay is turned off and does not describe permissions, leaving a modest gap.

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 explains what enabling means and that a saved card is required, and it clarifies that the customer can be an owner or office. It does not add detail about the customer_id format or what disabling does to pending scheduled charges.

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: turning auto-pay on or off for a customer. It is clearly distinct from siblings like customers_update or cards_setupLink because it names the exact setting being toggled.

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?

It gives a clear prerequisite for enabling auto-pay (a saved card) and explains the resulting billing behavior, which implies when to use it. It does not explicitly name alternatives or state when not to use this tool, so it falls short of full usage routing.

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