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

Beyond the annotations it discloses a real auth constraint (owners only, sign-in needed) and the important non-destructive nuance that overlapping bookings 'stay until moved' rather than being cancelled, plus what the response contains. Missing are idempotency/duplicate handling and how conflicts or errors are surfaced for this mutating tool.

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?

Dense and front-loaded: the permission requirement and purpose come first, then the parameter rules, then the return behavior. The telegraphic phrasing ('who is a team member's id') is efficient, though a touch terse.

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 mutating, 5-parameter tool with no output schema, the description covers purpose, permissions, the core optionality rules, and return content. It still leaves the note parameter and the date parameter unexplained, and says nothing about what happens when the block cannot be created.

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 0% schema description coverage the description carries the burden, and it does add real meaning for start/end (local HH:MM, both omitted means the whole day) and who (team member id, omitted means the whole business). However date and note are never explained, leaving two of five parameters undocumented anywhere.

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 makes clear this creates a busy-time block for either time off or externally booked time, and that the response reports overlapping bookings. It is specific about the resource and its effect, though the creating verb is carried mostly by the title/name rather than an explicit sentence.

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 states the conditions for use directly: owners only, sign-in required, and the two legitimate cases (time off, or time booked elsewhere to prevent double-booking). It does not name the counterpart tool (unblock_time) or state when to prefer add_booking instead, so no explicit alternatives or exclusions are given.

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