Get Calendar Event

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: the required calendar.read scope and the instruction to retain the concurrency token for the next conditional mutation, which is exactly the kind of behavioral detail an agent needs.

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?

Three terse sentences with zero filler: the action, the prerequisite permission, and the follow-up obligation are each front-loaded in order of need. Nothing is repeated from the schema or annotations.

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 three-parameter read tool with an output schema and full annotation coverage, the definition supplies the remaining essentials: scope requirement and concurrency-token handling. Only the absence of explicit alternatives keeps it from being fully complete.

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 100%, so event_id, mailbox_id and If-None-Match are already documented. The phrase "concurrency token" loosely connects to the ETag parameter, but the description adds no format or syntax detail beyond what the schema states, so the baseline 3 applies.

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?

The description uses a specific verb and scope ("Read one event"), which cleanly separates it from sibling listing tools like mailbox_list_calendar_events. It stops short of naming those siblings explicitly, so differentiation is inferred rather than spelled out.

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?

"Read one event before editing or deleting it" gives a concrete when-to-use trigger tied to the update/delete workflow, which is genuine routing guidance. It never states when not to use it (e.g., for bulk reads, use the list or changes tool), so it falls short of the top score.

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