calendar_upsert_event

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

Annotations already mark readOnly=false, idempotent=true, destructive=false. The description adds valuable context beyond these: it clarifies the write target (secondary calendar only), the in-place update behavior for existing iCalUIDs, and the prevention of duplicate events on re-runs. This meaningfully supplements the structured hints without contradiction.

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?

The description is three sentences long, front-loaded with the primary purpose, and every sentence adds meaningful detail (idempotency, secondary calendar scope, update-vs-create behavior). There is no fluff or repetition of schema content.

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 a rich schema and output schema present, the description adequately covers the core behavioral context: idempotency mechanism, calendar routing, and side effects. It does not cover authentication or error specifics, but those are not essential given the schema and annotations. The sibling list clearly separates read vs write tools.

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?

The tool description does not mention any parameter names, and schema description coverage is 0%. However, the input schema itself provides rich descriptions for every parameter (calendar_key, start_iso, ical_uid, etc.), including the stable UID derivation and calendar routing. The description's idempotency statement is conceptually helpful but largely redundant with the schema's ical_uid explanation, so a baseline score is appropriate.

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 clearly states 'Create or update an event in the secondary calendar' with the specific resource (calendar event), action (create/update), and scope (secondary calendar). It distinguishes from sibling tools like calendar_list_events (read-only) and emphasizes idempotency by iCalUID.

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 description provides clear context: it is for writing to the secondary calendar, never the primary, and is idempotent for repeat runs. It does not explicitly name alternative tools for read operations, but the contrast with calendar_list_events is implied and the 'never the primary calendar' guidance prevents misuse.

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