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

Annotations already declare readOnlyHint=false, openWorldHint=true, and destructiveHint=false, so the mutation and external-boundary profile is partly covered. The description adds valuable context beyond them: nothing is charged by this call itself and payment only occurs when a person opens the link.

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, purpose front-loaded, with the admin restriction and charging semantics following in order of importance. No wasted words, though 'upgrade from the free plan' is slightly narrowing context.

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 low-complexity two-parameter tool this covers the essentials, and there is no output schema to worry about. However it never states what is returned (presumably a link/URL) and leaves both parameters undocumented, so it is adequate but incomplete.

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% and the description says nothing about either parameter. planSlug (the required field) and the cadence enum (monthly/annual) are left entirely to the schema's type/enum hints, so the description fails to compensate for the coverage gap.

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+resource ('Create a hosted checkout link') with a clear qualifier ('to upgrade from the free plan'), which distinguishes it from the sibling billing_get. It does not name a sibling directly, but the checkout-link purpose is unambiguous.

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?

Provides a real precondition ('Workspace admins only') and scopes the use case to upgrading from the free plan. It gives clear context but names no alternatives or explicit when-not condition.

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