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

Beyond destructiveHint=true, the description discloses that cancellation takes effect at period end rather than immediately, that the caller must be an owner, and that the call is confirm-gated so it previews unless confirmed. That is exactly the behavioral context the annotation cannot express.

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 compact clauses with zero filler; the operation and its timing are front-loaded and the confirm gate is placed as a trailing qualifier where it does not obscure the main action.

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 2-parameter destructive tool with no output schema, the description covers timing, permission, and the preview/confirm contract. It could still note reversibility (i.e. that resume_organization_subscription exists) or what the preview returns, but nothing essential for a correct call is missing.

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 50%: the 'confirm' parameter is well documented in the schema and reinforced by the '(confirm-gated: previews until confirm: true)' note, but 'organizationId' has no schema description and the description only implies it via 'a gym's ... subscription'. Marginal added value over 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?

Specific verb + resource + scope: 'Cancel a gym's Trainzilla seat subscription at period end (owner only)'. The 'at period end' qualifier and 'seat subscription' phrasing distinguish it from cancel_client_subscription, close_organization, and change_organization_subscription_tier.

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 '(owner only)' parenthetical sets a clear authorization precondition for use. However, it never names an alternative for adjacent intents — e.g. resume_organization_subscription, refresh_organization_subscription, or change_organization_subscription_tier — so the agent must infer routing from sibling names alone.

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