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Get Mailbox Connection

mailbox_get_connection

Read-onlyIdempotent

Validate mailbox credentials and get connection details: team, label, permissions, and authorized mailboxes. Requires no mailbox storage access.

Instructions

Validate the current Mailbox credential and read its team, connection label, permissions and authorised mailboxes. No mailbox selection or mailbox storage access is required.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`If-None-Match`	No	ETag from a previous response. A match returns 304 with no body after rechecking authentication.

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": {
+              "credential": {
+                "additionalProperties": false,
+                "properties": {
+                  "id": {
+                    "type": "string"
+                  },
+                  "name": {
+                    "type": [
+                      "string",
+                      "null"
+                    ]
+                  },
+                  "type": {
+                    "enum": [
+                      "api_key",
+                      "oauth",
+                      "agent_token"
+                    ],
+                    "example": "api_key",
+                    "type": "string"
+                  }
+                },
+                "required": [
+                  "id",
+                  "type",
+                  "name"
+                ],
+                "type": "object"
+              },
+              "label": {
+                "description": "Display label for this connection.",
+                "type": "string"
+              },
+              "mailboxes": {
+                "items": {
+                  "additionalProperties": false,
+                  "properties": {
+                    "email": {
+                      "format": "email",
+                      "type": "string"
+                    },
+                    "id": {
+                      "type": "string"
+                    }
+                  },
+                  "required": [
+                    "id",
+                    "email"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              },
+              "permissions": {
+                "items": {
+                  "type": "string"
+                },
+                "type": "array"
+              },
+              "team": {
+                "additionalProperties": false,
+                "properties": {
+                  "id": {
+                    "type": "string"
+                  },
+                  "name": {
+                    "type": "string"
+                  }
+                },
+                "required": [
+                  "id",
+                  "name"
+                ],
+                "type": "object"
+              }
+            },
+            "required": [
+              "team",
+              "credential",
+              "label",
+              "permissions",
+              "mailboxes"
+            ],
+            "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": "ConnectionResponse"
+  }
+}

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

Addedv1.0.3Sep 8, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds meaningful behavioral context: it validates the current credential, reads specific connection-level data, and explicitly states that no mailbox selection or storage access is required. This is consistent with the annotations and goes beyond what they state.

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?

The description is two sentences with no wasted words. It front-loads the core purpose, lists the specific data returned, and adds a relevant scope constraint about mailbox selection and storage access. Every sentence 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?

For a simple read-only tool with one optional parameter, an output schema, and strong annotations, the description is largely sufficient. It explains the purpose, scope, and key behavioral constraint. It does not explicitly route agents to sibling tools, but that gap is minor given the tool's simplicity and rich structured metadata.

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 schema has one optional parameter, If-None-Match, with a description covering its ETag behavior, so schema description coverage is 100%. The tool description adds no additional parameter semantics beyond the schema, so the baseline score 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 states a specific action: validate the current Mailbox credential and read team, connection label, permissions, and authorised mailboxes. It clearly distinguishes itself from mailbox-content tools by noting that no mailbox selection or mailbox storage access is required, though it does not explicitly name or contrast sibling tools like mailbox_get_session.

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

Usage Guidelines3/5

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

The description implies its use for credential validation and connection metadata retrieval, and the 'no mailbox selection or mailbox storage access is required' line hints at when it is not appropriate. However, it provides no explicit guidance about when to prefer this tool over alternatives such as mailbox_get_session or sending_get_connection.

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