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

Annotations indicate idempotentHint=true and destructiveHint=false. The description adds that the row is deactivated (not deleted) and historical events stay, consistent with non-destructive behavior. It also mentions ownership enforcement, which is not in annotations. No 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?

Two concise sentences. First sentence gives the purpose. Second sentence adds key behavioral details. No wasted words, front-loaded.

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?

Describes input (id), behavior (ownership, soft delete), and side effects (historical events preserved). No output schema exists, so return value not required. Slight gap: no mention of success/error response, but overall adequate for a cancellation tool.

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 100% with one parameter 'id' described as 'Subscription id (uuid) returned by subscribe.' The description adds 'by id' but no additional meaning beyond the schema. Baseline 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 states 'Cancel a subscription by id.' The verb 'Cancel' and resource 'subscription by id' are specific. It clearly distinguishes from sibling tools like 'subscribe' and 'list_subscriptions'.

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?

It states 'Ownership is enforced — you can only cancel your own subscriptions.' This provides context on when to use (own subscriptions) and implicitly when not (others'). It also explains the deactivation behavior. However, no explicit alternatives or when-not scenarios beyond ownership.

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