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

The description goes beyond annotations by disclosing ownership enforcement, deactivation rather than deletion, and preservation of historical events via recent_alerts. This adds meaningful behavioral context that complements the readOnlyHint and destructiveHint annotations without contradiction.

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?

Three concise sentences, front-loaded with the core action, and every sentence adds value: operation, ownership rule, and lifecycle behavior. No redundancy or filler.

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 single-parameter tool with rich annotations, the description is fully complete. It covers what the tool does, who can use it, the effect (deactivation), and how historical data is preserved, leaving no significant gaps.

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 coverage is 100%, with the id parameter already described as 'Subscription id (uuid) returned by subscribe.' The description repeats 'by id' but adds no new parameter-level meaning, so the baseline of 3 applies.

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 by id') with a specific verb and resource. It distinguishes from sibling tools like subscribe and list_subscriptions by specifying the unsubscribe operation, and adds ownership and deactivation details that clarify its scope.

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 context: to cancel a subscription you own. It mentions ownership enforcement as a prerequisite, but does not explicitly contrast with alternatives like 'use subscribe to create' or 'list_subscriptions to view'. Still, the context is clear and actionable.

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