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

Annotations already indicate non-readOnly, idempotent, and non-destructive. The description adds valuable context: ownership is enforced, the row is deactivated (not deleted), and historical events remain accessible via recent_alerts. No contradiction with annotations.

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 with no wasted words. The action is front-loaded, and key behavioral details are included efficiently.

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?

Given the single parameter and no output schema, the description covers purpose, ownership, and side effects. It could mention the response or that it's idempotent, but annotations cover that. Overall quite 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 for 'id' is adequate ('Subscription id (uuid) returned by subscribe'), and schema coverage is 100%. The description does not add extra meaning beyond what schema provides, so a baseline score of 3 is appropriate.

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 'Cancel a subscription by id', specifying the verb and resource. It differentiates from sibling tools like 'subscribe' and 'list_subscriptions' by describing the action as cancellation and ownership enforcement.

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 description implies usage for canceling a subscription and mentions ownership enforcement, but does not explicitly state when not to use it or provide alternatives beyond the implicit sibling context.

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