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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false. The description adds meaningful context: the link is for a person to open externally, and cancel=true opens the cancellation flow directly, specifying that cancellation takes effect at the end of the paid period while a trial ends immediately.

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?

Two sentences, front-loaded with the core purpose and then the parameter behavior. Slightly awkward phrasing ('or cancelling, for the person to open') but no wasted content.

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 tool with no output schema and annotations covering safety, the description provides enough: it explains what is returned (a link), the parameter effect, and the external open-world nature. No critical gaps for correct invocation.

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 does: the single boolean parameter 'cancel' is explained in detail, including that true opens straight on cancelling and the timing consequence (end of paid period vs. immediate trial end).

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 it returns a link to Stripe's billing page covering card, invoices, and cancellation. It distinguishes the tool from siblings like remove_payment_account or cancel_scheduled by being a link generator rather than an action on the account, though it doesn't explicitly name an alternative.

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: 'for the person to open' and the cancel flag detail signal when to call it (when the user needs to access billing directly). However, there is no explicit when-to-use/when-not-to-use guidance or named sibling alternatives.

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