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

readOnlyHint=true already declares this is a safe read, so the description is not carrying the safety burden. It does add genuine behavioral context by disclosing that 'services' can be passed as a calendar value to fold services into the results, but says nothing about pagination limits or result ordering.

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 tight sentence with the core scope (date range) front-loaded before the optional filter, plus a compact endpoint reference. Nothing is wasted or padded.

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 6-parameter read tool with an output schema absent but every parameter fully documented in the schema and the read-only profile covered by annotations, the description supplies the essential framing. It could mention pagination behavior or that results omit extra fields unless requested, but nothing critical for a correct call is missing.

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% – dates, page, page_size, fields, and the 'services' calendar value are all documented in the schema. The description's calendar note largely restates the schema's own '"services" for services' wording, so it adds little beyond the structured fields; baseline 3 applies.

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 calendar events') plus scope ('between two dates, optionally for specific calendars'), so an agent immediately knows this is a read of event records rather than calendars or services. The distinction from elvanto_list_calendars and elvanto_create_calendar_event is implicit in the resource name but never called out explicitly.

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?

It conveys the required shape of a call (a start/end date range, optional calendar filter) which implies usage, but there is no explicit 'when to use this vs alternatives' guidance and no note that calendar IDs must first come from elvanto_list_calendars. No exclusions or prerequisite notes are given.

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