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

The description adds substantial behavioral transparency beyond annotations. It explicitly states that the tool does not process payment ('they pay on Stripe'), which clarifies a critical side effect. It also instructs to keep a session header ('Keep X-LyricPatch-Session privately saved in transport headers') and warns about retrying with the same session, aligning with idempotentHint. None of these details are present in annotations, and there is no 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?

The description is concise, with three sentences that front-load the core purpose and then add workflow details. Every phrase earns its place: price, credit amount, non-payment, authorizations, header handling, and retry guidance. No redundancy or fluff.

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?

Given the tool's complexity (6 required params, no param descriptions) and the existence of an output schema, the description covers the essential workflow: create/recover, require authorizations, keep header, give link, retry same session. It does not mention when to avoid using this tool (e.g., when a user has an account), but the signup-free context implies the appropriate use case. The output schema presumably handles return details, so the description is reasonably complete.

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 0%, so the description must compensate. It states 'Require explicit user authorizations,' which explains the boolean parameters as consent flags. However, it does not explain 'legal_version' or map each parameter to its role. While parameter names are self-explanatory (e.g., adult_attested, terms_accepted), the description's generic authorization note provides only partial compensation for the missing schema descriptions.

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 tool's purpose with a specific verb ('Create/recover'), a concrete resource ('signup-free Stripe checkout'), and precise details ($1.99 / 40 credits). It explicitly notes that the tool 'does not pay,' distinguishing it from payment-processing tools. This sets it apart from siblings like prepare_stripe_checkout and prepare_credit_purchase.

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 provides clear usage context: it says 'signup-free' and 'No wallet or website signup needed,' indicating when to choose this over account-based alternatives. It also gives retry guidance ('Retry with the SAME session, not a new purchase') and explains the workflow (give link to human, they pay on Stripe). However, it does not explicitly name alternatives or state when NOT to use this tool, so it falls 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.