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

Annotations only provide flags; description adds crucial detail: row is deactivated, not deleted, and historical events remain via recent_alerts. Goes beyond structured fields.

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: first states main action, second covers ownership and behavioral consequence. No fluff, front-loaded with verb.

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 tool with one parameter and no output schema, the description fully covers purpose, side effects, and linkage to recent_alerts. No 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 coverage is 100% for the single parameter 'id' with description 'Subscription id (uuid) returned by subscribe.' Description does not add beyond schema but is consistent.

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?

Clearly states 'Cancel a subscription by id' – specific verb and resource. Distinguishes from siblings like subscribe and list_subscriptions by mentioning ownership enforcement and deactivation.

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'), providing clear context. No explicit when-not-to-use or alternatives, but sufficient for typical use.

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