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

Adds substantial context beyond the annotations: the event is created without attendees because Microsoft auto-invites any event with attendees, the proposed attendees are placed in the body instead, the external attendee cap is 10, and the Calendars.ReadWrite scope is required. It also discloses the return payload since no output schema exists.

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?

Front-loads the critical constraint (draft, no attendees) in the first two sentences and keeps every sentence informational. It runs slightly long, but no sentence is filler given the non-obvious Microsoft invitation behavior it has to explain.

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?

With no output schema, the description usefully enumerates the return fields (event id, webLink, attendeesInvited, proposedAttendees) and covers the safety/scope profile. Only a few low-salience parameters (location, reminderMinutes, bodyContentType) remain undocumented, which is a minor gap.

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 only 38%, and the description clarifies the semantically tricky 'attendees' parameter (proposed, listed in body, not invited) and adds the 10-external-attendee cap. However, subject, body, location, bodyContentType, reminderMinutes and the UTC datetime formats get no additional explanation, leaving half the parameters on the schema alone.

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 (Compose) plus resource and scope (a draft meeting in the authorized user's own Outlook calendar). The 'draft only, nobody is invited' clause sharply distinguishes it from send_outlook_message, post_teams_channel_message, and compose_meeting_brief.

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?

Explicitly defines the workflow: create the draft, open it via the returned webLink, add attendees and send from Outlook. It also states the negative case — 'Onplana has no step that sends a meeting invitation' — so an agent knows not to look for a follow-up send tool.

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