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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: cancelled appointments are excluded by default and must be opted into, and the result set includes times, services, clients and ids (helpful since no output schema exists).

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 dense sentence that front-loads the action and resource, then packs the accepted input formats and the cancelled-inclusion switch without a wasted clause.

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-parameter read-only tool with no output schema, the description covers input formats, default behaviour and returned fields, which is nearly everything an agent needs. The only gap is the absence of any sibling routing or pagination/volume hint for a week-range query.

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 only 50% and include_cancelled has no schema description at all, so the description must compensate. It does: it enumerates every accepted "when" format including the range syntax ("2026-10-01 to 2026-10-07") and explains what include_cancelled toggles, adding meaning beyond the bare boolean type.

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 (List) and resource (the owner's appointments) with the scoping dimension (day or week) and the returned fields (times, services, clients, ids). It is clear on its own, but does not explicitly distinguish itself from near-siblings like my_calendar or my_bookings.

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 list of accepted "when" values (today, tomorrow, week, date, range) implies how to query, and include_cancelled implies the cancelled-case. However there is no statement of when to prefer this over my_calendar, my_bookings, or find_open_times, so the routing guidance is only implied.

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