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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description goes beyond that by disclosing the payload detail that the call returns — the guest list with each guest's address and acceptance status — which is genuinely useful since there is no output schema.

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?

A single well-formed sentence, front-loaded with the verb and scope, with no filler. It is efficiently sized, though it spends its only sentence on return content rather than routing or parameter guidance.

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 two-parameter read tool whose annotations cover the safety profile, this is minimally adequate, and the return-content note helps in the absence of an output schema. It still omits how an eventId is sourced and says nothing about the mailbox requirement beyond what the schema already states.

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 only 50%: mailbox is documented in the schema but eventId has no description at all. The description never mentions either parameter, so it does nothing to compensate for the undocumented eventId (e.g. its format or where to obtain it).

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 ("Read one event in full") and scopes it to a single event, which distinguishes it from the list/search siblings. It doesn't explicitly name those siblings, but the singular scope makes the distinction clear.

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?

Usage is only implicit: reading one event in full implies you use this when you need complete detail for a single known event rather than a listing. There is no explicit when-to-use statement, no mention of the list/search alternatives, and no note that an eventId must first be obtained from list_outlook_calendar_events or search_outlook_calendar_events.

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