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

Annotations already declare readOnly/idempotent/non-destructive, so the burden is reduced; the description still adds real value by disclosing the required calendar:read scope and the ownership model ('events belong to the user across all workspace assignments'). It does not mention result caps or pagination, which is the main remaining gap.

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?

Four sentences, front-loaded with purpose, then usage, then return contents, then scope/auth. No filler, and the reader's most important question (what do I get back) is answered before the operational caveats.

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?

There is no output schema, and the description compensates by enumerating the returned fields (subject, start/end, recording-bot subscription, event/series custom prompts). Combined with the ownership and auth notes, an agent has everything needed to call it 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 100%, so the baseline is 3, but the description adds non-obvious semantics for `workspace`: it is processing context, not an ownership filter, so passing it will not narrow results. That clarification meaningfully changes how an agent uses the parameter.

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, and scope: 'List the actor user's calendar events in a date range.' It is unmistakably distinct from the hub_list_calls / hub_search_calls siblings that operate on calls rather than calendar 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?

'Use this to find the eventId or seriesMasterId a prompt should attach to' gives a concrete selection context that routes the agent toward the hub_set_event_custom_prompt / hub_set_series_custom_prompt family. It stops short of naming an explicit alternative or a when-not-to-use case, so it falls just below the top band.

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