Purchase Credits

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

Description adds significant behavioral context beyond annotations: the async nature (not immediate charge/credit), the Stripe checkout session creation, automatic credit addition after payment, and authentication requirement. No contradiction with annotations.

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?

Two sentences with no filler. Front-loaded with the core purpose, then clarifies key behaviors. Every sentence is necessary and informative.

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 tool with one parameter and no output schema, the description covers authentication, workflow stages, and price reference. Annotations provide safety profile. Complete for selection and invocation.

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% with a well-documented enum parameter. The description lists the package options and references get_config for prices, which adds minor value. Baseline 3 is appropriate as the schema already fully describes the parameter.

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 clearly states the action: 'Starts a credit purchase: creates a Stripe checkout session and returns a payment URL.' It specifies the verb (starts), the resource (credit purchase), and the output (payment URL). It distinguishes from siblings by being the only purchase tool among retrieval/verification tools.

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 description explains the workflow: does not charge immediately, credits added after payment, requires authentication. It does not explicitly contrast with alternative tools, but the context of purchasing credits vs. other retrieval tools is clear.

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