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

Annotations indicate a mutating operation (readOnlyHint=false), and the description adds important behavioral context beyond that: 'The tool only creates a payment link; the user must open and complete payment in Stripe.' This clarifies that the tool does not finalize the purchase. However, it does not mention potential side effects like whether credits are reserved or any authorization requirements.

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 four sentences, each earning its place: purpose, usage, exclusion, and behavioral limitation. It is front-loaded with the core function and contains no redundant 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?

The tool has no output schema, but the description implies the return is a Stripe Checkout URL and indicates user action is needed. This is sufficient for basic invocation. It lacks detail on the response format or any post-payment flow, but given the moderate complexity and strong annotations, completeness is adequate.

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% with every parameter documented. The description adds overall context but does not elaborate on parameter-specific semantics beyond the schema. Baseline 3 is appropriate since the schema carries the full parameter meaning.

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?

The description opens with a specific verb and resource: 'Create a hosted Stripe Checkout URL for buying Uwear generation credits.' This clearly distinguishes the tool from siblings like get_user_credits and estimate_cost. The scope is unambiguous.

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?

Explicit usage criteria are provided: 'Use only when the user explicitly asks to buy, add, top up, or purchase credits, or when they ask how to continue after insufficient credits.' It also states a clear exclusion: 'Do not call during photoshoot planning unless the user requested checkout.' This gives the agent strong decision guidance.

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