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

With no annotations, the description carries the full burden. It usefully discloses the key non-obvious behavior — no email is sent to anyone — but leaves open whether fetching a Checkout link creates a Stripe session, whether links expire, whether it is idempotent, and what permissions are needed. Those are real open questions for a tool that touches Stripe state.

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?

Three short sentences, zero filler, with the core purpose front-loaded before the usage clarification and the 'does not email' exclusion. Every sentence earns its place.

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 one-parameter read tool with no output schema, the description covers what the tool produces (a payable Checkout link) and the key behavioral caveat (no email). The remaining gap is the return shape — a bare URL string versus a structured object — which is not stated and no output schema compensates for it.

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% for the single 'id' parameter, so the schema already documents it as 'Invoice id.' The description adds no guidance on id format, whether it accepts a number or a Stripe id, or what happens with an unknown id. Baseline 3 applies when the schema does the heavy lifting.

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 — 'Get the payable Stripe Checkout link for an invoice' — and names the concrete artifact returned (a payable link). The follow-up sentence clarifies the distinct purpose versus a generic invoice read like invoiceflow_get_invoice: it produces something a human can act on.

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?

'This is what you give a human so they can actually pay' gives a clear selection context, and 'Does not email anyone' rules out the mistaken assumption that this sends a payment request. It stops short of naming an explicit alternative sibling, but the contrast with the email-sending behavior is stated outright.

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