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

Description adds significant value beyond annotations by explaining that the row is deactivated (not deleted) and that historical events remain available via recent_alerts. This clarifies the non-destructive nature and lifecycle impact, which annotations only hint at with destructiveHint=false.

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 action, no wasted words. Efficiently conveys the core purpose and key behavioral 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?

Given the simple single-parameter tool, the description covers ownership, the deactivation behavior, and the tie to recent_alerts. No output schema needed; the description 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?

Schema coverage is 100% and the parameter description already states 'Subscription id (uuid) returned by subscribe.' The tool description does not add new semantic meaning beyond what the schema provides, so baseline 3.

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' with a specific verb and resource. It distinguishes from siblings like subscribe and list_subscriptions by mentioning ownership enforcement and deactivation vs deletion.

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 provides clear context: ownership enforced (only your own subscriptions) and explains the behavioral outcome (deactivated, not deleted). It does not explicitly list when not to use or compare to alternatives, but the context is sufficient for an agent.

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