Fluxmail

List labels

list_labels

Read-only

Lists Gmail labels or Outlook categories in a connected mailbox, optionally for a specific account, so you can inspect available organization options before assigning mail.

Instructions

List the Gmail labels or Outlook categories in 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": {
+          "id": {
+            "type": "string"
+          },
+          "name": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "id",
+          "name"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "data"
+  ],
+  "type": "object"
+}

First observedv0.1.0Jul 26, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, covering the safety profile. The description adds that the resource is Gmail labels or Outlook categories in a mailbox, which is useful provider context, but it does not disclose any additional behavioral details like system label inclusion or result ordering.

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?

A single, front-loaded sentence with no unnecessary words. It conveys the core action and provider nuance efficiently.

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?

Given the simple read-only nature, full parameter schema coverage, annotations, and an output schema, the description is nearly complete. The only minor gap is the lack of differentiation from list_folders, which could help an agent choose correctly.

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 description coverage is 100%, so the single optional accountId parameter is fully documented in the schema. The description does not add any meaning beyond what the schema provides, which is the baseline expectation when coverage is high.

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?

States a specific verb and resource ('List the Gmail labels or Outlook categories') and clarifies the provider-specific naming distinction. It is clear what the tool does, but does not explicitly distinguish itself from the sibling list_folders tool.

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?

The description gives no guidance on when to use this tool versus alternatives like list_folders, and no exclusions or prerequisites. It only implies basic usage from the verb.

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