List recent messages in an iCloud Mail mailbox and return headers only, so you can review email without changing read status.
List the most recent messages in a mailbox (newest first). Returns headers only.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| mailbox | No | Mailbox path, e.g. INBOX | INBOX |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only supply readOnlyHint=true; the description adds two genuinely behavioral facts beyond that: results are ordered newest-first and contain headers only (no message bodies). It stops short of noting pagination or that only the default limit is returned.
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 short sentences, front-loaded with the action and scoping, and the return-content caveat placed at the end. No filler or redundancy.
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?
With no output schema, the description correctly covers what comes back ('headers only') and the ordering, which is the essential information for a list tool. Missing only detail about paging or how to get full message bodies (get_message).
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 50% – 'mailbox' is documented in the schema, 'limit' is not (only its type/default/bounds). The description's 'most recent' wording loosely implies the limit's role but adds no paging or format semantics, so it neither compensates nor regresses.
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 ('List') plus resource ('messages'), with scope qualifiers: 'most recent', 'in a mailbox', 'newest first'. An agent can tell it apart from get_message and search_messages by the recency/listing framing, 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?
Usage is implied rather than stated – the recency-scoped phrasing suggests browsing a mailbox rather than targeted retrieval (search_messages) or fetching a single item (get_message). There is no explicit when-to-use, when-not-to-use, or named alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.