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

Beyond the annotations (readOnlyHint=false, idempotentHint=true, openWorldHint=true), the description discloses the two-step activation state machine: a new address receives one confirmation email, and the reminder is only switched on once the link is clicked. It also describes the divergent beep.me signed-in path where no confirmation is needed, which is exactly the kind of behavioral detail 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?

Purpose is front-loaded in the first clause, and each following sentence adds a distinct constraint (email confirmation, event-source restriction, beep.me exception). Slight redundancy remains: the beep.me 'leave email out' rule appears in both the description and the email property description.

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 six-parameter mutation with no output schema and a conditional confirmation flow, the description covers the mechanics an agent needs: prerequisite prompting, event sourcing, and the activation gate. It does not address re-submission behavior for an already-registered address or how to later modify/cancel, though stop_reminder exists as a sibling for part of that.

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 the baseline is 3, but the description adds real meaning for the two most consequential parameters: event_id must come from search_events, and email must be the user's exact address or omitted entirely under beep.me sign-in. Country, timezone, language, and remind_before_minutes are left to the schema, which is acceptable given full coverage.

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+resource pair: signing the user up for an email reminder tied to a public event. It also pins the input source ('an event that search_events returned'), which separates it from stop_reminder and my_reminders without needing to open any 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-to-use (events from search_events), explicit when-not ('never for personal appointments'), and a named alternative path (beep.me connected with sign-in → omit email, no confirmation). It also specifies the prerequisite interaction: ask the user for their email and never guess it.

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