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

DestructiveHint=true is present, and the description reinforces mutation with 'MUTATES' and adds the key behavioral consequence that access can be shortened, not just extended. It also grounds the behavior in the specific Memberful GraphQL mutation, going beyond the annotation.

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?

One tight, well-structured description with no filler. The mutation warning and purpose are front-loaded, and the GraphQL signature adds useful precision in very few words.

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 two-parameter mutation with complete schema coverage and a destructive annotation, this is complete: it identifies the target, parameters, units, consequence, and underlying operation. No output schema exists, but the description does not need to explain return values for this simple mutation.

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% and both parameters are already described in the schema, so the description does not need to compensate. It reinforces 'expiresAt in SECONDS' and maps params to the GraphQL mutation, which is mildly useful but largely redundant with the schema.

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 action ('change WHEN a subscription expires'), marks it as a mutation, and clarifies it can extend or shorten access. This distinguishes it from read-only sibling tools like get_subscription and list_subscriptions.

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?

The intended trigger is clear: use this when you need to alter a subscription's expiration date. It does not explicitly name sibling alternatives or exclusions, but no other sibling is a direct alternative for this mutation.

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