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

Beyond annotations (readOnlyHint=false, destructiveHint=false), the description adds meaningful behavioral details: ownership enforcement, soft-delete (deactivated not deleted), and the side effect that historical events remain available via recent_alerts. This enriches understanding of the tool's side effects.

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, front-loaded with the primary action. Every sentence contributes essential information (action, ownership, soft-delete behavior, and link to recent_alerts). No redundancy or fluff.

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?

With a single parameter, no output schema, and informative annotations, the description covers all necessary operational context: how to cancel, restrictions, and post-effects. It is complete for the tool's complexity.

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 input schema already provides complete description for the single parameter ('Subscription id (uuid) returned by subscribe'), with 100% coverage. The description only repeats 'by id' without adding new syntax or format details, so it doesn't elevate beyond the schema baseline.

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 the action ('Cancel a subscription') and the resource ('by id'), which is specific and unambiguous. It distinguishes itself from sibling tools like subscribe (opposite operation) and list_subscriptions (listing) by focusing on cancellation.

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 clear context: ownership is enforced (only your own subscriptions), and the deactivation behavior is explained. It implicitly guides when to use this tool (to stop alerts) and references recent_alerts for historical events, though it doesn't explicitly compare with alternatives.

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