calendar_event_add

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

With no annotations, the description still discloses the key behavioral facts: the event is persisted locally and is not sent anywhere externally, and defaults are spelled out (time omitted → all-day, date_end omitted → single day, repeat defaults to none). It omits the return value (no output schema) and any duplicate/ID behavior needed for later removal.

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?

Purpose and storage scope are front-loaded in one sentence, then each parameter is documented in a single line with a formatting example where it matters. No filler; length is proportionate to five undocumented parameters.

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 5-parameter mutation tool with no annotations and no output schema, the description covers inputs, defaults, and side-effect scope well. The remaining gap is the response shape and how a created event is referenced later (e.g., for calendar_event_remove).

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 0%, so the description must carry the full parameter burden and does: concrete accepted date formats, time formats, the all-day fallback, date_end semantics for multi-day events, the full repeat enum, and note as optional. This is well beyond what the bare schema provides.

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 first sentence states a specific verb and resource ("カレンダーに自分の予定を追加する") and adds a scope qualifier (saved to a local accumulation store, never transmitted externally). That distinguishes it in behavior from list/remove siblings (calendar_events, calendar_event_remove), though no sibling is named explicitly.

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?

Usage is implied by "自分の予定" (personal events) and the local-store scope, but the description never says when to use this versus calendar_event_remove or a space-events tool, and gives no prerequisites or exclusions. An agent can infer the context but is given no explicit routing rule.

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