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Get Mailbox Identity

mailbox_get_identity

Read-onlyIdempotent

Retrieve the mailbox sender identity and display name before composing replies to ensure the sender matches the mailbox.

Instructions

Use this to read the mailbox sender identity and display name. Use it before composing replies when the sender should match the mailbox identity.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`mailbox_id`	No	Mailbox public ID to target when the credential grants access to more than one mailbox. Omit when the credential is scoped to exactly one mailbox.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv1.0.8Sep 15, 2026

addedOutput schema / $schema

Added value: +"https://json-schema.org/draft/2020-12/schema"

removedOutput schema / additionalProperties
```
Removed value: -true
```

addedOutput schema / properties

Added value: +{
+  "result": {
+    "allOf": [
+      {
+        "properties": {
+          "meta": {
+            "additionalProperties": {},
+            "properties": {},
+            "type": "object"
+          },
+          "ok": {
+            "enum": [
+              true
+            ],
+            "type": "boolean"
+          }
+        },
+        "required": [
+          "ok",
+          "meta"
+        ],
+        "type": "object"
+      },
+      {
+        "properties": {
+          "data": {
+            "additionalProperties": false,
+            "properties": {
+              "bcc": {
+                "items": {
+                  "additionalProperties": false,
+                  "properties": {
+                    "email": {
+                      "example": "agent@example.com",
+                      "format": "email",
+                      "type": "string"
+                    },
+                    "name": {
+                      "example": "Support",
+                      "type": [
+                        "string",
+                        "null"
+                      ]
+                    }
+                  },
+                  "required": [
+                    "email",
+                    "name"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              },
+              "email": {
+                "format": "email",
+                "type": "string"
+              },
+              "html_signature": {
+                "type": "string"
+              },
+              "id": {
+                "description": "Identity ID",
+                "type": "string"
+              },
+              "may_delete": {
+                "description": "Whether the mailbox service allows this identity to be deleted.",
+                "type": "boolean"
+              },
+              "name": {
+                "type": "string"
+              },
+              "reply_to": {
+                "items": {
+                  "additionalProperties": false,
+                  "properties": {
+                    "email": {
+                      "example": "agent@example.com",
+                      "format": "email",
+                      "type": "string"
+                    },
+                    "name": {
+                      "example": "Support",
+                      "type": [
+                        "string",
+                        "null"
+                      ]
+                    }
+                  },
+                  "required": [
+                    "email",
+                    "name"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              },
+              "text_signature": {
+                "type": "string"
+              }
+            },
+            "required": [
+              "id",
+              "name",
+              "email",
+              "reply_to",
+              "bcc",
+              "text_signature",
+              "html_signature",
+              "may_delete"
+            ],
+            "type": "object"
+          },
+          "meta": {
+            "additionalProperties": false,
+            "properties": {
+              "request_id": {
+                "example": "req_clxxxxxxxxxxxxxxxxxxxxxxxxx",
+                "type": "string"
+              }
+            },
+            "required": [
+              "request_id"
+            ],
+            "type": "object"
+          }
+        },
+        "required": [
+          "data"
+        ],
+        "type": "object"
+      }
+    ],
+    "unevaluatedProperties": {
+      "not": {}
+    },
+    "x-fastmcp-top-level-schema": "MailboxIdentityResponse"
+  }
+}

addedOutput schema / required
```
Added value: +[
+  "result"
+]
```

First observedv1.0.0Jul 13, 2026

TDQS

A3.8/5.0

Behavior3/5

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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds context about reading sender identity and display name before composing replies, but does not disclose additional behavioral details such as error conditions or auth requirements. No contradiction with annotations.

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?

Two short sentences carry the purpose and the key usage context without any filler. The information is front-loaded and every word contributes to the agent's understanding.

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?

For a simple read-only tool with one optional parameter, an output schema, and strong annotations, the description is nearly complete. It could slightly improve by mentioning when to prefer mailbox_list_identities, but this is not a major gap given the clear composing-replies scenario.

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?

The parameter schema has 100% coverage and already explains mailbox_id clearly, including when to omit it. The description does not add parameter-specific guidance, but with such strong schema coverage, a baseline of 3 is appropriate.

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?

The description clearly states the tool reads the mailbox sender identity and display name, using a specific verb and resource. It does not explicitly differentiate itself from sibling tools like mailbox_list_identities, but the singular 'mailbox identity' and the composing-replies context imply the intended use.

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?

The description gives an explicit use case: use this before composing replies when the sender should match the mailbox identity. It lacks explicit exclusions or alternatives, but the context is clear enough for an agent to select this tool for the stated scenario.

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