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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond that: no word on whether the folder set is flat or hierarchical, whether the list is paginated, or what happens when accountId is omitted, which is the main behavioral question for this tool.

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 with no filler is structurally fine, but at seven words it is terse to the point of under-specification rather than genuinely efficient.

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?

For a listing tool with an undocumented optional accountId, no output schema, and a crowded sibling namespace, the description leaves the key questions (which account, what the return looks like, how folders relate) unanswered.

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 0% and the description never mentions the single accountId parameter, so the agent gets no indication of what it does or that it is optional (required=0). It fails to compensate for the documentation gap.

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 clear verb and resource ('List the mailbox folders'), so the agent knows the operation immediately. It does not differentiate from siblings like list_labels, list_accounts, or list_emails, leaving room to doubt which listing tool applies.

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?

There is no when-to-use guidance, no mention of alternatives (e.g., list_labels for labels rather than folders), and no prerequisites such as whether an accountId is needed or which account is defaulted. The agent must infer all routing.

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