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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no behavioral context beyond purpose - no pagination, filtering behavior, or return shape for a tool flagged openWorldHint.

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?

A single front-loaded sentence with the action first and the rationale trailing. No wasted words and nothing buried.

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 trivial read-only, one-parameter list tool with no output schema, the description covers what is needed to invoke it. It could say more about what the list contains or how to use the returned calendar IDs, but the gap is minor.

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?

The single required parameter location_id has no description in the schema (0% coverage). The description's mention of a 'HighLevel sub-account' weakly implies location_id identifies that sub-account, but it adds no format or sourcing guidance. Baseline 3 given one undocumented param.

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 and resource ('List the calendars') scoped to a HighLevel sub-account, and hints at the relationship to appointment filtering, which separates it from siblings like highlevel_appointments. It stops short of naming a sibling directly, so it is clear but not maximally differentiated.

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 clause 'so appointments can be filtered to one of them' implies when the tool is useful, but there is no explicit when-to-use, when-not-to-use, or named alternative. Usage must be inferred from the downstream purpose.

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