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

Although annotations already indicate a mutating, external-world action (readOnlyHint=false, openWorldHint=true), the description adds valuable context: the tool returns a URL and does not process payment within the LLM. This clarifies the exact nature of the side effect and prevents the agent from attempting to complete a transaction.

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 two sentences: the first states purpose, the second adds a critical constraint (payment cannot happen internally). No wasted words, and the structure is front-loaded with the core action.

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 a simple schema, full schema coverage, annotations, and an output schema, the description covers all necessary context: what the tool does, the key limitation, and the expected deliverable (a URL). Nothing essential is missing for an agent to invoke it correctly.

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?

The schema provides 100% coverage for both parameters (tier and billing_period) with clear descriptions, so the description itself adds no additional parameter semantics. Baseline 3 is appropriate as the schema does the heavy lifting; no further elaboration is needed.

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?

Description clearly states the tool creates a Stripe Checkout URL for upgrading a clariBI subscription, using a specific verb ('Create') and resource ('Stripe Checkout URL'). It distinguishes itself from sibling tools like check_pricing and get_billing_status by focusing on the upgrade/payment action, leaving no ambiguity about its function.

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 implies use when a user needs to upgrade their subscription and explicitly warns that payment cannot happen inside the LLM, guiding the agent to return the URL instead of simulating payment. It lacks an explicit mention of when not to use (e.g., for downgrades) or reference to alternative tools, but the context is clear enough for most cases.

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