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

Annotations already cover readOnly/idempotent/destructive, but the description adds real behavioral context beyond them: the overlap rule (any part of an event inside the window puts it on both days), the ambiguity of an empty list vs. no calendar connected, and the read-only guarantee restated as user-facing scope.

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?

Four short sentences, front-loaded with what the tool does, then scope, then defaults, then edge-case semantics. No sentence is filler; each carries a distinct operational fact.

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?

With an output schema present, return values need no explanation, and the description covers the remaining gaps an agent needs: default window, overlap behavior, empty-result ambiguity, and the complementary tasks tool.

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%, so the baseline is 3; the description nevertheless adds window semantics not in the schema — the ANY-overlap matching rule and the explicit contrast with xtiles_list_tasks' single-due-date matching. It does not add further detail on page/per_page, which the schema already handles.

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 (events from the user's connected Google and Outlook calendars), and explicitly contrasts the tool with xtiles_list_tasks. An agent can distinguish it from the ~37 siblings without opening the 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 explicit defaults ('with no dates, returns today'), states what an empty result does and does not mean, and routes the agent to call both this and xtiles_list_tasks for a complete day view. When-to-use and when-to-combine are both covered.

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