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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, so the description is not burdened with safety disclosure. It adds the purpose of obtaining event.id but does not disclose pagination, filtering semantics, or return format. Given the annotations cover the main behavioral profile, a 3 is appropriate – it adds some context but lacks deeper behavioral details.

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 exceptionally concise – two sentences with no filler. The primary purpose is stated first, and the secondary use case is added efficiently. Every word earns its place, making it easy to parse and act upon.

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?

Despite being a simple read-only tool, it has 18 parameters and no output schema. The description does not mention pagination (cursor, limit, offset), filtering options, or what the response looks like. An agent would need to infer much from parameter names and the few schema descriptions. For a tool of this complexity, the description is insufficiently complete.

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?

With only 22% schema description coverage and 18 parameters, the description was expected to compensate by explaining how to search or filter, but it does not. It merely says 'list or search' without detailing which parameters enable searching. The schema descriptions for calendar_id, start, end, and account_id help, but many parameters (e.g., title, location, attendees, is_cancelled) remain undocumented in both schema and description, leaving agents without guidance.

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 clearly states the tool's purpose: 'List or search events inside one resolved calendar.' It specifies a concrete action (list/search) and resource (events), and distinguishes its role by noting it is used to obtain event.id before reading, updating, or deleting an event, which separates it from event-specific operations like calendar_get_event.

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 clear context: it is the entry point for obtaining event IDs and implies the need for a resolved calendar (likely from calendar_list_calendars). However, it does not explicitly mention alternatives like calendar_get_event for when the ID is already known, nor does it state exclusions. Still, the guidance is actionable and implies the correct workflow.

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