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

Goes well beyond the annotations, which only declare destructive/idempotent/open-world hints. The description discloses the read-then-write version check, that concurrent edits are refused rather than overwritten, that version-less events are left unchanged, that attachments are untouched, the one-hour undo_id lifetime, and the underlying PUT endpoint.

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 dense single paragraph, but front-loaded with the WRITE marker and ordered from semantics to permission to recurrence to side effects. Nearly every clause carries operationally useful information, with only minor run-on tendency.

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?

No output schema exists, and the description covers the return shape (event plus undo_id with its lifetime), the version-check behavior, recurrence handling, and side-effect scoping. An agent has everything needed to call this correctly.

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 47%, but the description compensates on the parameters that matter: partial-update semantics ('fields you leave out keep their value'), redit usage, and the occurrence-id format. Booleans like signup_enabled and comments_enabled remain unexplained, but those are largely self-describing.

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?

Opens with 'WRITE: change fields of an event', giving a specific verb, resource, and mutation type. It is immediately distinguishable from teamup_create_event and teamup_delete_event without opening 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 clear conditional guidance: pass redit with single/future for recurring events, use the occurrence id format, and modify permission is required. It routes to teamup_undo_event_action for the undo path, but does not state when to prefer a sibling like teamup_create_event instead of this tool, so routing is clear but not exhaustive.

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