Buy credits — get a Stripe checkout link

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

Adds genuinely non-obvious behavior beyond the annotations: the call itself is free, checkout happens in the browser, and credits post automatically after checkout — this materially clarifies the destructiveHint=false and non-idempotent profile. It does not mention that repeat calls spawn multiple independent sessions, and there is mild tension with openWorldHint=false given the described Stripe hand-off, though that is a debatable interpretation rather than a clear 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 key fact (free to call, returns a link) before the pricing details, and every sentence is relevant. It is somewhat dense with dollar figures duplicated from the schema, which is the only waste.

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 correctly supplies the return value (checkoutUrl) and post-checkout outcome, which is what an agent needs to chain a payment flow. It omits precedence when both amount and package are supplied, a real ambiguity in a 0-required-parameter schema.

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 100% and the description largely restates the same amounts, package tiers and $0.001/credit conversion already documented in the schema properties. It adds little syntax or selection guidance beyond what the schema provides, so the 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 ('Top up your MyMedi-AI credits') and immediately names the concrete mechanism and return value ('Creates a Stripe Checkout session and returns a checkoutUrl'). No sibling tool touches billing, so an agent can identify it at a glance.

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?

Explains the crucial usage fact that calling it charges nothing and that the agent must open the URL for payment to complete, and presents the two acquisition paths (amount vs package) as alternatives. It does not state exclusions or prerequisites (e.g. account must be authenticated), which keeps it short of a 5.

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