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

Adds substantial behavior far beyond the annotations: the tool never writes directly, returning status='confirmation_required' plus action_id and plan_token, with the write deferred to confirm_action. It also discloses per-item failure handling (failed items surface in 'skipped' with index and reason while the rest still land), which is critical for a batch mutation. Nothing here conflicts with readOnlyHint=false / destructiveHint=false.

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 batch purpose, then the item shape, then the exclusion, then failure semantics, then the confirmation requirement — each clause carries distinct, non-redundant information. Dense but no wasted sentences.

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?

Although there is no output schema, the description explains the relevant return surface (status, action_id, plan_token, skipped with index and reason), so an agent knows exactly what to expect. Combined with the confirmation flow and partial-failure rules, nothing essential for correct invocation 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?

With 0% schema coverage and the schema only declaring 'items' as an untyped array of objects, the description is the sole source of the item shape, enumerating title, start_at, end_at?, all_day?, availability?, event_type?, location?, notes? with optionality. It stops short of giving value formats or allowed values for start_at, availability, and event_type, and does not mention the maxItems=100 / minItems=1 bounds present in the schema.

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 and resource ('Create SEVERAL unrelated events') and pins down the batch scope, immediately separating it from the single-event sibling by noting that repeating events belong to create_event. An agent can distinguish create_events from create_event without opening either 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 explicit routing: unrelated events go here, a repeating event goes to create_event with 'recurrence'. It also describes the confirmation workflow (call confirm_action with the action_id/plan_token) and the partial-failure behavior, so the agent knows both when to choose this tool and what to do after calling it.

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