list_received_emailsList inbound emails received on domains with inbound enabled.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Page size (1–100) | |
| cursor | No | Opaque cursor for the next page | |
| domain | No | Only messages received on this domain |
| Name | Required | Description | Default |
|---|---|---|---|
| has_more | No | True when another page follows | |
| next_cursor | No | Pass as cursor for the next page; null on the last page | |
| received_emails | Yes | Inbound emails, newest first |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "has_more": {
+ "description": "True when another page follows",
+ "type": "boolean"
+ },
+ "next_cursor": {
+ "description": "Pass as cursor for the next page; null on the last page",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "received_emails": {
+ "description": "Inbound emails, newest first",
+ "items": {
+ "properties": {
+ "attachment_count": {
+ "type": "number"
+ },
+ "attachments": {
+ "items": {
+ "properties": {
+ "content_id": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "content_type": {
+ "type": "string"
+ },
+ "data": {
+ "description": "Base64 content, when included",
+ "type": "string"
+ },
+ "filename": {
+ "type": "string"
+ },
+ "size": {
+ "description": "Bytes",
+ "type": "number"
+ }
+ },
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "auto_submitted": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "bounced": {
+ "type": "boolean"
+ },
+ "cc": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "created_at": {
+ "description": "ISO 8601",
+ "type": "string"
+ },
+ "domain_id": {
+ "type": "string"
+ },
+ "domain_name": {
+ "type": "string"
+ },
+ "from": {
+ "type": "string"
+ },
+ "html_body": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "id": {
+ "description": "Received email id",
+ "type": "string"
+ },
+ "in_reply_to": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "mail_from": {
+ "description": "Envelope sender",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "message_id": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "rcpt_to": {
+ "description": "Address it was delivered to",
+ "type": "string"
+ },
+ "received_at": {
+ "description": "ISO 8601",
+ "type": "string"
+ },
+ "received_with_ssl": {
+ "type": [
+ "boolean",
+ "null"
+ ]
+ },
+ "references": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "spam_status": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "status": {
+ "type": "string"
+ },
+ "subject": {
+ "type": "string"
+ },
+ "text_body": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "to": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "id"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "received_emails"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, establishing this is a safe read. The description adds the domain-scoping constraint but no pagination behavior, ordering, or empty-result semantics beyond what the schema hints. With annotations covering the safety profile, this is adequate but not rich.
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 with no waste. However, at this brevity it could afford one more clause to route the agent or clarify scope, so it's efficient but slightly under-informative.
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?
Output schema exists, so return values needn't be described, and annotations cover safety. What's missing is differentiation from list_emails and any pagination or ordering context. For a list tool with a rich schema and annotations, this is minimally complete but leaves the sibling-routing gap.
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 100%, so limit, cursor, and domain are fully documented in the schema. The description adds no syntax or format detail beyond what's already provided. Baseline 3 is appropriate when the schema does the heavy lifting.
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 (List) and resource (inbound emails) with a scope qualifier (domains with inbound enabled). Clear what it does, though it doesn't explicitly differentiate from sibling list_emails, which presumably lists outbound/sent emails. An agent can infer the inbound/outbound split, but it's not spelled out.
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 phrase 'on domains with inbound enabled' implies usage context (only meaningful when inbound is configured), but there's no explicit when-to-use vs alternatives. It doesn't say to use get_received_email for a single message or how this differs from list_emails. Guidance is implied rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.