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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuine value beyond that by disclosing the shape of the response (including attachment metadata, version and change history) and the occurrence-id semantics, though it says nothing about permissions or pagination/traversal for large collections.

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 resource in two tight clauses and follows with the occurrence-id rule. The return-field list is long but earns its place since no output schema exists; the trailing raw HTTP route is mildly redundant for an MCP tool but harmless.

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 single-parameter read tool with no output schema, the description compensates well by enumerating returned fields and clarifying the id format. Nothing an agent needs to invoke it correctly is missing.

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 meaning the schema pattern alone does not convey: the 'rid-<unix start>' structure is explained as selecting one occurrence of a recurring event. That interpretation of an otherwise opaque id format is a real contribution.

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 resource ('One event by id') and enumerates exactly what it returns, including title, times, sub-calendars, recurrence, signups, comments, attachments, version and change history. This makes it trivially distinguishable from siblings like teamup_list_events, teamup_search_events and teamup_list_changed_events.

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 concrete selection guidance for a key case: use the occurrence id ('123-rid-<unix start>') to fetch a single occurrence of a recurring event. It does not explicitly state when to prefer this over search_events/list_events or note that the id must already be known, but the context is clear.

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