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

The description goes beyond annotations by clarifying ownership enforcement, that the row is deactivated not deleted (aligning with destructiveHint=false), and that historical events stay accessible via recent_alerts. This adds significant behavioral context beyond the structured annotations.

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 two sentences with no wasted words. The first sentence states the core action and constraint, the second explains the side effect. Every sentence earns its place.

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 one-parameter tool with no output schema, the description covers all necessary aspects: purpose, ownership constraint, effect on data (deactivation vs deletion), and consequence for historical tracking. It is complete given the tool's simplicity.

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 has 100% coverage with a description for the required 'id' parameter stating it's a UUID returned by subscribe. The description restates 'by id', adding minimal extra value, but the schema already does well. Since coverage is high, baseline is 3, and the description adds the origin hint (returned by subscribe), so 4 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 starts with a specific verb 'Cancel' and resource 'subscription by id', clearly distinguishing it from its sibling 'subscribe'. It adds ownership enforcement and deletion behavior, making the purpose unambiguous.

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 states ownership enforcement and the deactivation vs deletion behavior, providing context for when to use this tool. It also mentions that historical events remain available via recent_alerts, guiding the agent on related tools. However, it does not explicitly list when not to use it or compare with alternative cancellation methods.

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