update_event

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It reveals that passing None leaves a field unchanged and imposes a time_zone requirement when changing datetime fields. Yet it does not disclose what happens if fields are omitted (as opposed to passed as None), whether the operation is destructive, or how errors are handled (e.g., invalid event_id). The disclosed behaviors are useful but incomplete for a mutating operation.

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 two sentences long, with the purpose front-loaded and a critical constraint following. It avoids redundancy and uses precise language ('Pass None to leave a field unchanged'). The structure is efficient and easily parsed, though it could include more detail without sacrificing conciseness.

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 12 parameters, no annotations, and no output schema, the description is severely under-specified. It does not explain return values, error conditions, or provide usage examples. It covers only the null semantics and the time_zone rule, which is insufficient for an agent to reliably invoke the tool across all scenarios. The complexity demands far more contextual detail than provided.

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 is the only source for parameter meaning. It adds the null semantics for all fields and the time_zone dependency, but it does not explain the format of start_datetime/end_datetime, the meaning of body_type, is_all_day, is_online_meeting, or include_raw. Many parameters are self-explanatory by name, but the description provides minimal additional value beyond the null behavior, leaving agents to guess at specifics.

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 states a specific verb and resource: 'Patch fields of an existing event.' This distinguishes it from create_event and delete_event by focusing on modification of an existing entity. However, it does not enumerate which fields can be patched, leaving some ambiguity about scope. Sibling tools like list_events, get_event, and create_event are clearly separate in purpose.

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 a specific usage rule: 'If you change start_datetime or end_datetime, you must also pass time_zone.' This is a conditional instruction for correct invocation. However, it does not explicitly guide the agent on when to choose this tool over create_event (e.g., when the event already exists) or when to avoid it. The usage guidance is limited to a single dependency and lacks alternative selection context.

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