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

Annotations already cover readOnlyHint and openWorldHint, so the safety profile is set. The description adds non-obvious behavior: date bounds are inclusive and supplying exactly one date is an error, plus the underlying endpoint path. That is meaningful context beyond the annotations.

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 purpose is front-loaded, but the second sentence crams the endpoint path, parameter behavior, and a sibling cross-reference into one run-on clause. The raw '/calendar-service/events' detail adds implementation noise without helping an agent invoke the tool.

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 two-optional-param list tool with no output schema, it covers both invocation modes, the inclusivity rule, the single-date failure case, and where the same data appears elsewhere. Return format is left unstated, but no output schema exists and the annotations plus description are otherwise sufficient.

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% (baseline 3), but the description adds real meaning: startDate/endDate must be supplied together, are interpreted inclusively, and a lone date throws rather than being ignored. This coordinates the two optional params beyond their individual schema docs.

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 resource and scope: every calendar event between two inclusive dates, or all events when no dates are given. It is clear what the tool returns, though it does not explicitly distinguish itself from the singular get_calendar_event or get_all_day_events siblings.

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?

Explains the two invocation modes (both dates given -> filtered; no params -> all events) and warns that a single date throws. It also names the related getScheduledWorkouts month feed where events also surface, giving context for choosing between sources, though it states no explicit when-not condition.

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