list_messagesList incoming emails in a mailbox, newest first, with short previews. Use when automatic code extraction fails and you need to inspect the mail manually.
List what has arrived in a mailbox, newest first, with a short preview of each. Use it when the code extraction found nothing and you need to look at the mail yourself.
| Name | Required | Description | Default |
|---|---|---|---|
| mailboxId | Yes | Mailbox id from create_mailbox |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of disclosing side effects, permissions, or read-only nature. The description only implies a read-only list operation but does not explicitly state that it has no side effects or whether it requires special permissions. This lack of transparency is a significant gap.
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?
The description is concise, consisting of two sentences that front-load the primary action and then provide usage context. There is no unnecessary verbosity or repetition.
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 description gives a clear trigger scenario for use and describes the output format at a high level (newest first, short previews). It does not detail error conditions or pagination, but for a simple list tool this is acceptable and does not impede correct usage.
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 sole parameter 'mailboxId' is described as 'Mailbox id from create_mailbox', which provides cross-tool context and clarifies the expected value. The schema coverage is 100% for the single parameter, and the description adds meaningful information beyond the type.
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 clearly states the tool's purpose: listing messages in a mailbox, with explicit details about ordering ('newest first') and content ('short preview of each'). It also provides a concrete use case ('when the code extraction found nothing'), making the purpose unambiguous.
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 explicit guidance on when to use the tool ('Use it when the code extraction found nothing and you need to look at the mail yourself'), which is helpful. However, it does not explicitly mention when not to use it or contrast it with sibling tools like read_message, but the context is sufficient for most scenarios.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.