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

With no annotations, the description carries the full behavioral burden. It usefully discloses that this creates an external Stripe Checkout link and the £2.99 price, but it omits whether link creation itself charges the user, link expiry, authentication needs, and handling of invalid postcodes.

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?

A single front-loaded sentence with no waste. The action, price, and scope are stated immediately.

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 simple one-parameter tool, the description covers the action, cost, and subject. But with no output schema and no annotations, it should clarify the returned link's form or lifetime and the required postcode format to be fully 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 for the single parameter. It says 'one postcode' but does not add format, validation, or regional expectations, adding only minimal meaning beyond the parameter name and string type.

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 states a specific verb ('Create') and resource ('Stripe Checkout link') with the price and subject ('full report on one postcode'). It distinguishes the purchase-link action from sibling report/summary tools implicitly, but does not explicitly name or contrast them.

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?

Usage is implied: create this link when a user wants to buy the full report for a postcode. However, the description does not state when not to use it, prerequisites, or how it relates to postcode_report and postcode_summary.

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