Proton Suite Agent

List emails in a mailbox

proton_list_emails

Read-onlyIdempotent

Lists recent emails newest first from a mailbox with offset and limit pagination, returning UID, sender, recipient, subject, date, flags, and size; for message bodies, use proton_get_email.

Instructions

Lists recent emails in a mailbox, newest first. Use pagination with offset+limit. Returns UID, from, to, subject, date, flags, size. Does NOT return the body — use proton_get_email for that.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "proton_list_emails"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No
`offset`	No
`mailbox`	No		INBOX
`response_format`	No	markdown table, json, or concise bullet list (fewer tokens)	markdown

Output Schema

Name	Required	Description	Default
`count`	Yes
`items`	Yes
`total`	Yes
`offset`	Yes
`mailbox`	Yes
`has_more`	Yes
`next_offset`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv1.6.0Sep 30, 2026

addedInput schema / properties / response_format / description

Added value: +"markdown table, json, or concise bullet list (fewer tokens)"

changedInput schema / properties / response_format / enum

Previous value: -[
-  "markdown",
-  "json"
-]New value: +[
+  "markdown",
+  "json",
+  "concise"
+]

First observedv0.8.0Jul 28, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish readOnly/idempotent/openWorld, so the bar is low. The description adds real behavioral context beyond them: newest-first ordering, that pagination is offset+limit based, and the exact shape of returned metadata with the body excluded.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences with the core action front-loaded, followed by the pagination mechanic and then the exclusion. No filler, every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values need not be spelled out, and annotations cover the safety profile; the description still volunteers the field list and body exclusion. The remaining gap is mailbox scoping semantics, which is left entirely to the schema default.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 25%, so the description must carry weight and it partially does by naming offset+limit as the pagination pair. However the mailbox parameter (default INBOX) and the limit bounds/behavior are never explained, and the listed fields (UID, from, to, subject...) are return values, not parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Lists recent emails in a mailbox') plus ordering ('newest first'), and explicitly carves itself away from proton_get_email by declaring it does not return the body. An agent can distinguish this from the sibling fetch tool without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit alternative for the body case ('use proton_get_email for that') and states the pagination mechanism. It stops short of routing the agent against proton_search_emails, which is the other obvious sibling for email retrieval, so guidance is clear but not exhaustive.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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