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

Annotations are empty, so the description carries the full disclosure burden. It delivers: async-only behavior, approval link, immediate-application exception, `applied: true` semantics (order placed and hold, not charge), card-decline outcome, and a required terms-consent step. This is exemplary transparency.

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 dense yet every sentence earns its place: core purpose, examples, async behavior, exception, financial semantics, and required consent. It front-loads the action and examples before edge cases, and there is no filler.

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 tool with no output schema and no annotations, the description covers invocation semantics, return-link behavior, follow-up action, conditional immediate application, authorization flow, card handling, and required user consent. Nothing essential is missing for correct selection and calling.

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 already 100%, but the description adds value with natural-language usage examples, the additive vs. total-distinction, mutual exclusivity implied by examples, and the significance of `applied: true` for interpreting the result. It enriches rather than repeats the 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?

States a specific action ('Change how many phones the rental covers') tied to a clear resource, then gives concrete examples (`add: 1`, `add: -2`, `phones: 5`). This makes it clearly distinct from sibling tools like start-rental-tool or phone-control-tool.

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?

Describes when the change is only filed versus applied immediately (standing allowance), explicitly instructs polling get-billing-request-tool for approval, and mandates accept_terms before calling. It lacks an explicit 'use start-rental-tool for initial rentals' exclusion, but the provided context is strong.

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