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

With no annotations, the description does disclose meaningful behavior: it creates an external Stripe-hosted checkout and requires human action to complete payment. It omits whether the URL expires, whether repeated calls create duplicate sessions, and what permissions or account state are needed.

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?

One short sentence, front-loaded with the action and ending with the critical human-in-the-loop constraint. 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 one-parameter tool with no annotations and no output schema, the description covers the core purpose and the human payment step but leaves the parameter meaning, URL lifetime, and result shape unexplained. Adequate but with clear gaps.

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 0% for the single required parameter credits_amount, which is an undescribed integer. The description only hints that it corresponds to a 'pack', giving no units, allowed values, or relation to the packs listed by credit_packs, so it fails to compensate for the schema gap.

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: creating a Stripe Checkout URL for a credit pack. This distinguishes it from sibling read tools such as credit_packs and credits_history. It does not explicitly name those siblings, so it falls short of a 5.

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 clause 'a human must open it to pay' implies the tool only prepares a payment link and that the agent cannot complete the purchase itself, which is useful usage context. However, it never says when to call this versus credit_packs (to discover pack sizes) or what to do after the URL is returned.

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