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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so no contradiction exists. The description adds meaningful behavior beyond the annotations, especially the plan-dependent default date range ('a year back and a year forward on Pro, and the free window either side of today') and the cross-calendar search scope.

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, front-loaded with the core behavior and free of filler. However, the phrase 'and the free window either side of today' is slightly imprecise—it doesn't specify the window size or clearly frame the free-versus-Pro distinction—so it saves words at a small cost to clarity.

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 no output schema, the description covers the essential invocation details: searchable fields, calendar scope, required query, and default date behavior. It stops short of describing result shape, ordering, or pagination, but an agent has enough to select and call the tool 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, but the description adds real semantic value: it explains which fields query searches (title, description, location, attendees) and clarifies the runtime meaning of omitting from/to. This goes beyond the schema's bare 'Words to look for' and date descriptions.

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 uses a specific verb and resource: 'Find events whose title, description, location or attendees contain a phrase.' It also states the scope ('Searches every imported calendar'), which clearly distinguishes it from list-style siblings like events_list. The purpose is immediately unambiguous.

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 gives clear situational context: this is a full-phrase search across all imported calendars, and it explains the default time window when from/to are omitted. It does not explicitly name an alternative tool or exclusion, but an agent can infer when search semantics are appropriate versus a plain calendar list.

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