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

Annotations already declare the safe-read, idempotent, closed-world profile, so the lower bar applies. The description still adds real behavior: default window of ±31 days, a hard 366-day cap, per-calendar scoping via calendarId, and the touching-endpoint rule that defines what counts as a conflict.

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?

Five dense sentences with no filler; the core purpose leads, and defaults, constraints, and edge-case semantics follow in priority order. Every sentence carries information an agent needs.

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?

An output schema exists, so return values need no explanation. With 5 parameters, 0 required, all described at 100% coverage, and the description adding defaults, caps, and the boundary rule, nothing needed to call this correctly 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 coverage is 100%, so the baseline is 3. The description goes beyond it by restating the ±31-day defaults and the 366-day window constraint inline, and by tying start/end to the pre-create check, giving the parameters workflow meaning the schema alone does not.

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: 'Find overlapping events in the authenticated user calendar.' It also pins down the conflict semantics ('Intervals that only touch at an endpoint are not a conflict'), which lets an agent distinguish this from get_free_slots or search_events without opening a schema.

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?

Gives two concrete usage modes: scanning a from/to window for existing overlaps, and checking a proposed start/end slot 'before create_event.' That routing to create_event is explicit. It stops short of naming when to prefer get_free_slots instead, so no exclusions are stated.

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