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

Description discloses that the row is deactivated (not deleted), aligning with 'destructiveHint: false'. Ownership enforcement is also noted. Annotations provide idempotentHint and readOnlyHint, and the description complements them 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?

Two sentences, front-loaded with the action, no wasted words. Every sentence provides essential information.

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 purpose, ownership, and behavioral effect (deactivation). It is complete given the 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%, so description adds minimal value. It mentions 'Subscription id (uuid) returned by subscribe,' which connects to a sibling but doesn't add significant meaning beyond the schema's own description.

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?

Description clearly states 'Cancel a subscription by id.' This is a specific verb+resource combination, and the name 'unsubscribe' distinguishes it from siblings 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?

States ownership enforcement ('you can only cancel your own subscriptions') and explains the effect ('deactivated, not deleted'). This provides context for when to use, though it could explicitly mention when not to use (e.g., for permanent deletion).

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