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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely new context beyond them: the nullable return shape ({ workspaceId: uuid | null }) and the required user-settings:read scope, which tells the agent an auth precondition 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?

Three compact clauses, front-loaded with the action and its meaning, then the return shape, then the scope requirement. No filler and nothing repeated from the schema.

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 present, the description steps in to state the return shape and nullability, plus the auth scope — the two things an agent would otherwise have to guess. Minor gap: no guidance on the account/workspace parameters or what a null result means operationally.

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?

Both parameters are optional and documented at 100% schema coverage, including the multi-account failure mode (ACCOUNT_REQUIRED) and workspace override semantics. The description adds nothing about them, but with full schema coverage the baseline of 3 applies.

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?

A specific verb+resource ('Get the user's default workspace') with an added functional gloss explaining what the default workspace actually controls (routing of unassigned calendar events). It does not, however, distinguish itself from the nearby sibling find_my_workspace or from hub_get_workspace, which an agent could easily conflate.

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?

Usage is implied through the routing explanation (call this when you need to know where unassigned events land), but there is no explicit when-to-use/when-not framing and no mention of the obvious alternative find_my_workspace or of the write counterpart hub_set_default_workspace.

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