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

Annotations only declare the read/create/destructive profile; the description goes well beyond them, disclosing that the link saves the card, holds one month per phone, that nothing is charged immediately, when the hold is actually charged (on assignment or admin confirmation), and that an admin must assign concrete phones. This is exactly the behavioral detail the annotations cannot convey.

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?

Front-loaded with the core action and then ordered logically (charge model, parameter choice, legal prerequisite, follow-up). It is dense but every sentence carries information, with only minor duplication of the accept_terms wording already present in the schema.

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?

With no output schema, the description carries the full burden and does so: it explains what the tool returns (a Checkout link), the post-call workflow, and how to observe results via get-billing-tool. An agent has everything needed to call this correctly and to tell the user what happens next.

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 schema already documents the phones/items mutual exclusion, quantity bounds, and the ISO-2 country default. The description restates the either/or choice without adding syntax or edge-case detail beyond the schema, so baseline 3 applies.

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 verb and resource — 'Order phones by returning a Stripe Checkout link' — and immediately clarifies the transactional semantics (no charge at the link). An agent can distinguish this from sibling order tools like request-phones-tool and the submission/account tools without opening any schema.

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?

Gives explicit context: choose `phones` (+ optional `country`) for one country or `items` to spread across several, plus the hard prerequisite of showing the terms/privacy URLs and obtaining agreement. It also names the follow-up (poll get-billing-tool). It does not, however, contrast itself with the similarly named sibling request-phones-tool, so the routing guidance is incomplete.

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