Add guests to an appointment

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

Annotations are all false (readOnlyHint, idempotentHint, destructiveHint all false). The description adds that guests receive invitations and updates, which discloses a side effect (notifications sent) beyond the schema. However, it does not fully disclose other behaviors like whether the operation can be undone or if there are limits. With no annotations, the description partially carries the burden.

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?

The description is just two short sentences with no redundant information. It gets straight to the point and is appropriately sized.

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 2 required parameters and no output schema, the description covers the core action and effect. It lacks mention of potential errors or explicit prerequisites beyond 'existing appointment,' but overall adequate.

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?

The description mentions 'guest email addresses' hinting at the emails parameter and 'existing appointment' hinting at appointmentId, but does not explain format, requiredness, or constraints. With 0% schema coverage, the description should compensate but does so only minimally.

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 uses a specific verb 'Add' and resource 'guest email addresses to an existing appointment' and mentions the consequence 'They receive the invitation and updates.' This clearly distinguishes it from sibling tools like book_appointment (creates new) or cancel_appointment (removes).

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?

The description states the tool adds guests to an existing appointment, implying the appointment must already exist. However, it does not explicitly contrast with alternatives like book_appointment for adding guests during creation or reschedule_appointment for modifying guests. No when-not-to-use guidance is provided.

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