purchase_credits

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

No annotations are provided, so the description must fully disclose behavior. It only mentions creating a session and returning a URL, but omits side effects (e.g., charge timing, idempotency, auth requirements, failure modes). For a payment tool, this is a significant gap.

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 sentence, no redundant words, important details front-loaded. Highly concise.

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 payment tool with no output schema and no annotations, the description is too brief. It lacks return format, error handling, security context, and post-session behavior. Incomplete given the tool's complexity.

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 50% (only pack has schema description). The description adds 'credit packs' context but does not explain api_key beyond its existence. The pack values are already listed in the schema. Baseline 3 is appropriate as the description adds minimal extra value.

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 it creates a Stripe Checkout session to buy credit packs and returns a payment URL. The verb 'Create' and resource 'Stripe Checkout session' are specific, and it distinguishes from sibling tools focused on agents, skills, balance, etc.

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?

No explicit guidance on when to use this tool vs alternatives is given. However, sibling tools are in different domains, so confusion is minimal. The description lacks prerequisites or scenarios for use.

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