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

Annotations already declare a non-read-only, non-destructive, non-open-world write. The description adds one behavioral fact beyond them: that the created calendar is a secondary one, not the primary. It says nothing about permissions, quota limits, or whether the new calendar is immediately usable, so it is only modestly additive.

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 sentence with the action front-loaded and the rationale following a dash. No filler, no repetition of the title.

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 no output schema, the description omits what the call returns — notably the new calendar's ID, which the agent would need to add events to it. Combined with 50% parameter coverage and minimal annotations, a competent but incomplete picture.

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 only 50%: mailbox and timeZone are documented in the schema, but name and description are bare. The description mentions no parameters at all, so it does not compensate for the undocumented half or clarify naming conventions for the calendar.

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 ("Create a new secondary calendar") and adds the scope qualifier "secondary," which distinguishes it from primary-calendar operations. It does not explicitly differentiate itself from the near-identical sibling create_outlook_calendar, so it falls short of a 5.

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 clause "useful for keeping a client's or project's events separate from the personal one" implies a use case but never states when to use this versus create_outlook_calendar, or that the mailbox must be authorized first. Usage is inferred rather than directed.

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