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

Adds substantial context beyond annotations: partial-update semantics ('fields you leave out stay as they are'), series-wide effect on recurring events, immediate member visibility, default confirmation per call with an opt-out, and an owner-approval wait. These traits materially change how an agent should invoke it and are not recoverable from the hints.

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?

Front-loaded with the core action and mutation scope before the operational caveats. Almost every clause earns its place, though the confirmation/approval sentences are slightly compressed and could read ambiguously at first pass.

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 12-parameter mutation with no output schema, the description covers the essential unknowns: partial update, recurring-series scope, approval/confirmation flow, and admin restriction. An agent has enough to call it correctly.

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 earns more by disclosing cross-parameter behavior — 'a new start keeps the old length unless duration_minutes is given' — which the schema alone does not express. It does not otherwise elaborate on individual parameter formats.

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/update) plus the resource (a calendar event) and enumerates the mutable facets (title, time, place, access). 'Edits one event' cleanly separates it from create_event/delete_event siblings without opening any schema.

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?

Explicitly marks the tool as admins-only and explains that recurring events change the whole series, which drives when-to-use decisions. It does not name sibling alternatives (create_event, delete_event) as the ideal bar requires, but the operational context is clear.

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