update_event

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

With no annotations, the description carries the full burden and does so well. It discloses partial update behavior ('Only the fields you specify will be changed'), recurrence handling via apply_to, the confirmation response with event ID and updated field names, and specific error conditions (event ID not found, start_date not before end_date). This is rich, non-obvious behavioral context beyond a simple update statement.

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 front-loaded with the core purpose and each subsequent sentence delivers distinct value: partial update behavior, recurrence, return format, error conditions, and a pointer to get_event. There is no redundancy or filler; every sentence earns its place.

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?

Given 8 parameters, no output schema, and no annotations, the description covers the essential operational context: what updates, how partial updates work, recurrence handling, return value, and error cases. It stops short of a 5 because it does not clarify how to clear a field (omission leaves unchanged, so no obvious mechanism) or discuss calendar scope/permissions, but these are minor gaps given the schema already covers parameter definitions.

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 coverage is 100%, so the baseline is 3. The description adds important semantic context about parameter usage: omitted fields remain unchanged, apply_to distinguishes instance vs series updates, and start_date must precede end_date. These enrich understanding beyond the individual property descriptions, earning a 4.

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 starts with 'Update a calendar event in Outlook', using a specific verb and resource. It clearly distinguishes update semantics from sibling create/delete/get tools by highlighting partial updates, and the context of recurring events with apply_to. This makes the tool's purpose unmistakable.

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 useful guidance: it explains when to use apply_to for recurring events, warns that event_id must exist, and explicitly suggests 'Use get_event to review current values before updating.' However, it does not explicitly contrast with create_event or offer when-not-to-use exclusions, so it stops short of a full 5.

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