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

Beyond the annotations, it discloses meaningful behavior: repeated calls reschedule rather than duplicate, and whatsapp/telegram are rejected for free users. This adds real context about side effects and restrictions without contradicting the 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?

Three sentences, each earning its place: the operation, the reschedule semantics, and the plan-based restrictions. The example is compact and informative with no filler.

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 four-parameter mutation with no output schema, the description covers the essential call semantics, source of ids, rescheduling behavior, and failure condition for Pro-only methods. It could additionally state what a successful response returns or whether deliveryMethod defaults to email, but those are minor 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 75%, and the description adds value by explaining that itemId comes from search/fetch, giving a full example shape, and clarifying deliveryMethod plan restrictions. It does not repeat the schema's message limits, but it supplements rather than duplicates.

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 opens with a specific verb plus resource: 'Set (or reschedule) a reminder on a saved item, by its id'. It also tells where ids come from and differentiates itself from siblings like cancel_reminder and list_reminders by framing the operation as set/reschedule.

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?

It gives clear usage context: ids come from search/fetch, one reminder per item, and calling again reschedules. It does not explicitly state when to use a sibling alternative such as cancel_reminder, so it falls just short of fully explicit when/not guidance.

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