list_foldersRetrieves an account's mail folders and shows each folder's role, total messages, and unread count, so you can inspect mailbox structure before choosing a folder.
List folders of an account with their special-use role (inbox, sent, drafts, trash, junk, archive, all, flagged) and message/unread counts.
| Name | Required | Description | Default |
|---|---|---|---|
| account | Yes | Account id from list_accounts |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful behavioral context by naming the returned fields (special-use roles plus message/unread counts), though it omits ordering or nesting behavior.
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 zero preamble; the parenthetical list is dense but informative rather than wasteful.
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 one-parameter read-only listing tool with no output schema, the description supplies enough return-value detail: folders, special-use roles, and message/unread counts. The only minor omission is whether folders are nested or ordered, which does not block correct invocation.
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?
There is one parameter and schema coverage is 100%, with 'account' already documented as an id from list_accounts. The description only restates 'of an account' and adds no syntax or selection detail beyond the schema.
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?
The description opens with a specific verb ('List') and resource ('folders of an account'), then enumerates the special-use roles and counts it returns. This clearly distinguishes it from siblings like list_accounts and search_messages, which target different resources.
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?
It implies the tool is for enumerating folders for a given account, but never states when to choose it over list_accounts or search_messages, nor any prerequisites beyond the schema's account reference. Usage is only inferable from the purpose, so it meets the minimum viable bar.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.