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

Annotations already declare readOnlyHint=false and destructiveHint=false, but the description adds substantial context: partial-update semantics ('changes the fields you pass and leaves the rest'), the fields it deliberately excludes, no guest notification, reversibility ('undone by calling it again with the old values'), safe-to-run-without-confirmation, and an API-key access requirement. This is well beyond what the annotations convey.

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-loads the action and field list, then layers exclusions, reversibility, and auth in a logical order. Efficient overall, though the 'Perfect Venue:' prefix and the 'so it runs without asking first' clause add mild verbosity.

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 10-parameter mutation tool with no output schema, it covers the essentials an agent needs: what changes, what is excluded, reversibility, notification behavior, and auth. The only minor gap is that per-field formats are left entirely to the schema.

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 100%, so the schema already documents all 10 parameters; baseline is 3. The description enumerates the updatable fields, which adds a light mapping layer, but it introduces no format or syntax detail (e.g. space IDs, owner email) beyond the schema.

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) and the exact set of updatable fields (date, time, guests, spaces, event type, owner, internal notes), which maps cleanly onto the resource. It distinguishes itself from the sibling set_event_status by name, so an agent can separate it from a status-mutation tool without opening either 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 scopes what it does not handle ('does not change the proposal items, prices or the status') and routes to the alternative 'use set_event_status for the status'. It also clarifies it reaches no guest, ruling out guest-notification side effects. This is genuine when/when-not guidance.

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