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

Annotations only supply readOnly=false/openWorld=true/idempotent=false/destructive=false. The description goes well beyond them by disclosing that link creation charges nothing, that Stripe expires an unpaid link after 24 hours, that an abandoned checkout incurs no charge, and that a published invitation's payment_status stays paid.

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?

Dense but front-loaded: purpose first, then the no-charge/expiry behavior, then the event_id branching. Every sentence carries operational information, though the paragraph is long enough to be slightly demanding.

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?

An output schema exists, so return-format detail is unnecessary, and the description nonetheless covers the full purchase-to-confirm workflow including post-payment verification and retry steps. Nothing an agent needs to invoke it correctly is missing.

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% so baseline is 3, but the description adds real semantic value: it ties event_id to the draft publishing shortfall and instructs passing publishing_price.credits_to_buy as quantity, and specifies omitting event_id for account credits and guest changes.

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?

States a specific verb and resource (start a Stripe checkout link) and enumerates the concrete goods being bought (account credits, publishing, phone guests, design generations). It is clearly distinguishable from all siblings, none of which handle payment.

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?

Explicitly routes on event_id: use it to buy a draft's publishing shortfall, omit it for account credits or published-event guest changes. States a hard precondition ('Do not call it before the host has seen and agreed to the amount') and names the follow-up siblings (lemonvite_get_invitation, lemonvite_publish_invitation, lemonvite_get_account).

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