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

With no annotations supplied, the description carries the full burden and does disclose the most important trait: this creates a draft and will not send without confirmation. It omits other relevant behavior such as whether the event is persisted to the calendar, whether attendees are notified on creation, whether invitation emails are suppressed, and what permission scope is needed.

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?

Two short sentences, zero filler, with the core action stated first and the critical safety constraint second. Nothing in it is redundant or wasteful.

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 write tool with no annotations and no output schema, the description covers the action and the confirmation gate but leaves gaps: it does not describe what is returned (e.g., a draft or event identifier the agent would need to later send), nor what happens to attendees. Given the absence of an output schema, some indication of the result would have closed the loop.

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% with per-field descriptions including ISO-8601 format examples, so the schema already does the heavy lifting. The description adds no parameter-level meaning beyond that, which is the baseline 3 case.

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 gives a specific verb (Draft) and resource (Google Calendar meeting invite), so an agent immediately knows what object is being produced. It is distinguishable from calendar_list_events by implication, but it does not explicitly differentiate itself from other drafting siblings such as gmail_create_draft or github_create_pr_draft.

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?

The sentence 'Does NOT send invites without explicit user confirmation' effectively tells the agent a confirmation step is required before sending, which is implied usage guidance. However, there is no explicit when-to-use versus when-not-to-use guidance and no pointer to check_action_safety, a sibling that likely governs exactly this kind of write action.

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