Fluxmail

List sender addresses

list_send_as

Read-only

List the sender addresses available for a mailbox so you can choose the correct From address when composing or sending email.

Instructions

List the sender addresses available for a mailbox.

Input Schema

Name	Required	Description	Default
`accountId`	No	Account to operate on. Optional when exactly one account is connected.

Output Schema

Name	Required	Description	Default
`data`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.19.0Oct 30, 2026

changedInput schema / properties / accountId / anyOf

Previous value: -[
-  {
-    "minLength": 1,
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 512,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

Changed3 schema fields changedv0.15.0Oct 17, 2026
- addedInput schema / properties / accountId / anyOf
```
Added value: +[
+  {
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]
```
- removedInput schema / properties / accountId / minLength
```
Removed value: -1
```
- removedInput schema / properties / accountId / type
```
Removed value: -"string"
```
Changed1 schema field changedv0.11.1Oct 1, 2026
- removedOutput schema / $schema
```
Removed value: -"http://json-schema.org/draft-07/schema#"
```

Changed1 schema field changedv0.11.0Sep 26, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "data": {
+      "items": {
+        "additionalProperties": true,
+        "properties": {
+          "email": {
+            "type": "string"
+          },
+          "isPrimary": {
+            "type": "boolean"
+          },
+          "source": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "email",
+          "isPrimary",
+          "source"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "data"
+  ],
+  "type": "object"
+}

Addedv0.9.0Sep 16, 2026

TDQS

B3.2/5.0

Behavior3/5

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

Annotations already establish readOnly, non-destructive, closed-world semantics, so the safety profile needs no repetition. The description adds only the per-mailbox scoping concept and says nothing about ordering, pagination, or whether this reflects verified/aliased addresses.

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

Conciseness4/5

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

One front-loaded sentence with no filler. It is appropriately short but borders on under-specified rather than effortfully concise.

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

Completeness3/5

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

With an output schema present and the lone parameter well documented, the core call mechanics are covered. What is missing is the connective context — that these addresses are the valid 'from' values for sending tools — which matters for correct downstream use.

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 100% and the single optional accountId parameter is fully documented ('Optional when exactly one account is connected'). The description adds no further parameter meaning beyond implying mailbox scoping.

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

Purpose4/5

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

Names a specific verb ('List') and resource ('sender addresses'), scoped to a mailbox. It is clearly distinct from list_accounts, list_folders, and list_labels, though it does not name those siblings explicitly.

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

Usage Guidelines2/5

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

There is no indication of when an agent should call this versus related list tools, no mention that results feed into send_email/forward_email as the from-address, and no note on behavior when no sender addresses are configured.

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