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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered without the description. The description adds modest value by naming the specific folder roles that appear in results, but says nothing about ordering, completeness, or behavior when no account is connected.

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 front-loaded sentence that identifies the resource first and then the payload detail. No filler or repetition; the only mild inefficiency is that the role examples are illustrative rather than actionable.

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, full param coverage, and annotations covering safety, the description need only say what is listed and it does. It falls short of complete because it omits the folders-versus-labels distinction, the one disambiguation an agent actually needs given the sibling set.

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% and there is one optional parameter, so the schema fully documents accountId including the single-account default. The description mentions no parameters at all, leaving the baseline of 3 appropriate since the schema does all the work.

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?

Specific verb (list) plus resource (folders in a mailbox) with concrete examples of the roles returned. An agent can tell it apart from list_emails or search_emails, but it never distinguishes folders from the sibling list_labels, which is the most likely confusion point in this toolset.

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 only implied by the read-only, inventory nature of the tool. There is no statement of when to call this versus list_labels, nor any note that it is typically a prerequisite step before move_emails or archive_emails. No exclusions or prerequisites are given.

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