calendar_update_event

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

With no annotations, the description carries the full burden. It does disclose two non-obvious behavioral traits: patch semantics ('Only the fields you pass change') and that recurring events with exceptions are updated as a whole series. But it says nothing about permissions, behavior on an unknown uid, timezone handling, or what the call returns.

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?

Two sentences, no filler, and the core patch semantics are front-loaded ahead of the exclusion caveat. Every clause carries information an agent needs.

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 mutation tool with 8 parameters, zero schema descriptions, and no annotations or output schema, the description leaves too much undefined — most critically the date/time format and timezone semantics of the required data. The series caveat is valuable, but the parameter-level gap is large.

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% across 8 parameters, so the description must compensate and largely does not. Only uid gets any treatment (implicitly, via the list-events hint); start/end formats, timezone_name vs. start timezone interaction, and calendar_name scope are all left undefined.

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 ('Change fields of') and resource ('an existing event'), and identifies the lookup key (uid, sourced from calendar_list_events). This clearly separates it from calendar_create_event and calendar_delete_event by implying mutation of an existing entity, though it never names those siblings 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?

Gives a clear operational prerequisite (obtain uid from calendar_list_events) and an explicit when-not: 'Not for recurring events with exceptions.' That exclusion is genuinely selective guidance. It stops short of naming an alternative tool for the recurring-with-exceptions case, so it isn't a full 5.

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