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

Annotations already declare non-read-only, non-idempotent, destructive, open-world. The description adds real context beyond them: the phone rings within seconds (latency), it burns one call from the user's quota (the actual cost), and it does not alter the schedule (bounded side effect). That is exactly the extra disclosure annotations cannot carry.

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 tight sentences plus a single arg line; the immediate-action summary and the guardrail are front-loaded, and every sentence adds 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?

Covers side effect (quota), reversibility (schedule unchanged), timing, and the parameter source; an output schema exists so return values need no explanation. Nothing needed to call it correctly is missing.

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 description coverage is 0%, so the schema documents nothing about reminder_id. The description compensates by stating it is the 'Reminder to test' and where to obtain it ('from list_reminders'), though it gives no format or validation details.

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?

States a specific verb and resource — 'Place an immediate test call for a reminder' — with the immediacy qualifier that separates it from create_reminder or list_reminders. An agent can distinguish this from every sibling without opening the schema.

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?

Gives explicit when ('only when the user has asked to test') and when-not ('never repeatedly'), plus a concrete constraint (consumes one quota call). It also routes the agent to list_reminders for the required ID.

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