list_foldersList top-level mail folders with IDs, display names, and unread/total counts. Retrieve folder IDs to access messages in inbox, sent items, drafts, or archive.
List the mailbox's top-level mail folders with their ids, display names, and unread/total counts. Use a folder id or well-known name (inbox, sentitems, drafts, archive) with list_messages.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool read-only, idempotent, and non-destructive. The description adds meaningful behavioral context by clarifying the listing is 'top-level' and by disclosing the exact returned information (ids, display names, unread/total counts). This goes beyond what annotations provide.
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?
Two sentences, no filler. The first sentence states the action and output shape; the second provides the most valuable follow-up instruction. The structure is well front-loaded and every sentence earns its place.
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?
The tool is a zero-parameter, safe, idempotent listing endpoint. The description fully covers return content and the natural next step (passing a folder id to list_messages). No output schema is present, but the description explicitly names the output fields, so nothing essential is missing.
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?
The tooool has zero parameters and the input schema has no properties, so there is no parameter semantics for the description to add. The 0-parameter baseline of 4 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?
The description states a specific verb ('List') and resource ('the mailbox's top-level mail folders') and lists the returned fields: ids, display names, and unread/total counts. It also distinguishes itself from message-level siblings like list_messages by specifying folder scope.
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?
The description gives clear follow-up guidance: 'Use a folder id or well-known name (inbox, sentitems, drafts, archive) with list_messages.' It implies when this tool is useful—when you need folder identifiers to query messages—and names list_messages as the relevant sibling. It does not explicitly exclude other siblings, but that is unnecessary for a simple top-level listing tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.