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

The description discloses key behavioral traits beyond the annotations: ownership enforcement ('only cancel your own subscriptions') and the non-destructive nature ('row is deactivated, not deleted'). This adds meaningful context that annotations alone do not provide, such as the persistence of historical events in recent_alerts.

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?

The description is three sentences, front-loaded with the core action, then efficient elaborations on ownership and deactivation. Every sentence earns its place with no filler or repetition of schema details.

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 simple single-parameter tool with no output schema, this description covers all necessary context: the action, the constraint (ownership), the side effect (deactivation), and the downstream availability of historical events. No significant gaps remain.

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?

The schema already describes the id parameter well ('Subscription id (uuid) returned by subscribe'). The description reinforces this by saying 'by id' and adds ownership semantics ('your own subscriptions'), which gives the parameter practical meaning beyond the schema's technical definition.

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 opens with a specific verb+resource: 'Cancel a subscription by id.' This clearly distinguishes it from siblings like subscribe and list_subscriptions, and the title confirms the alert context. It also adds ownership enforcement, further clarifying the tool's exact role.

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 when to use this tool (when you need to cancel a subscription) and provides important context about consequences (deactivation vs deletion, historical events remain via recent_alerts). It does not explicitly name alternatives or state exclusions, but the sibling set and clear purpose make the usage context obvious.

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