list_foldersLists folders in a mailbox with message and unread counts, helping you identify where messages are stored and which folders have unread email.
Lists the folders in a mailbox with message and unread counts.
| Name | Required | Description | Default |
|---|---|---|---|
| account | No | Which mailbox to use, by its name or email address. Configured: "Example". Can be left out, there's only one. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The readOnlyHint=true annotation already establishes the safety profile and the description is consistent with it. The description does add one piece of behavioral value beyond annotations — that results include message and unread counts — but it says nothing about folder hierarchy (flat vs nested), depth, or scope of the counts.
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?
One front-loaded sentence with no filler; the core action and the returned fields are both stated immediately.
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 simple single-optional-parameter read tool with no output schema, the description is minimally adequate and partly compensates for the missing output schema by naming the returned counts. However, it omits whether folder structure is hierarchical, which matters given siblings like move_emails that target folders.
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 the single 'account' parameter is fully documented in the schema, including that it may be omitted. The description adds no further parameter meaning, which is acceptable at a baseline of 3.
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 and resource ('Lists the folders in a mailbox') plus the useful detail that results carry message and unread counts. It does not distinguish itself from siblings like list_mailboxes or check_inbox, so an agent must infer the difference from names alone.
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 statement of when to use this versus list_mailboxes, check_inbox, or search_emails, and no prerequisites are mentioned. Usage is only inferable from the tool name; a mailbox-vs-folder distinction would have been the natural place to add routing guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.