Lists visible mail accounts and mailboxes with message counts, helping you identify available folders before searching or reading messages without changing any data.
Lists the mail accounts and mailboxes that are visible under the current settings, with message counts. Changes nothing.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| note | No | ||
| accounts | Yes |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so "Changes nothing" largely restates structured data. The genuine added value is the visibility scoping ("visible under the current settings"), which signals results are permission-dependent, but nothing is said about result size or limits.
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 names the resource before its qualifiers, with no padding. The trailing "Changes nothing" clause is mildly redundant given the readOnly annotation, costing a perfect score.
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 zero-parameter, read-only listing tool with a full output schema and complete annotations, the description covers purpose, output content, and permission scoping. Only edge-case behavior (empty results, counting semantics) is left unstated, which is minor.
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 tool takes zero parameters and the schema is closed (additionalProperties: false), so there is no parameter semantics to document. Baseline 4 applies; the description correctly implies no inputs are needed.
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 specific verb ("Lists") and a specific resource ("mail accounts and mailboxes") plus what is returned ("message counts"). The resource is clearly distinct from the message-level siblings (search_messages, get_message, get_thread), though no sibling is named explicitly.
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?
"Visible under the current settings" implies a discovery/setup use, but the description never states when to prefer this over the sibling tools or what to do next. Usage is inferable rather than spelled out.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.