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

Annotations only say readOnlyHint=false, destructiveHint=true, openWorldHint=false; the description goes further by clarifying no charge/transfer occurs, that payment happens in the human's browser, that the same connector and usr_live_ key are reused, and that no new wallet is created. The 'does not charge and does not transfer funds' claim sits in mild tension with destructiveHint=true, but it reads as disambiguation of an over-conservative hint rather than a direct contradiction.

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 action and price, followed by effect disclosure and sibling routing. 'Same connector and same usr_live_ key. Not a new wallet.' is slightly cryptic/redundant but still earns its place as scope clarification.

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 zero-param, no-output-schema tool, it covers the return value (a session URL), the effect (no funds moved), and the next step. It omits details like session expiry or what else the response contains, which are minor.

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?

Zero parameters, so the schema carries no semantic load; the description usefully explains that the target wallet is implicit ('this connected wallet') and that the same credentials are reused.

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 (create) and resource (a $26 / 13 Stripe Checkout session URL) scoped to 'this connected wallet', which an agent can immediately distinguish from the read-only get_credits sibling.

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?

Explicitly routes the agent: 'Do not call this to read balance — use get_credits', naming both the exclusion and the correct alternative. It also implies the trigger condition (a human must open the URL and pay on Stripe).

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