Fluxmail

Read thread

get_thread

Read-only

Read paginated messages from an email thread, returning up to 50,000 body characters per page.

Instructions

Read a page of messages in an email thread, with at most 50,000 body characters per page.

Input Schema

Name	Required	Description
`pageSize`	No
`threadId`	Yes
`accountId`	No	Account to operate on. Optional when exactly one account is connected.
`pageToken`	No
`bodyFormat`	No

Output Schema

Name	Required	Description	Default
`data`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields 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"
+  }
+]

changedInput schema / properties / pageToken / anyOf

Previous value: -[
-  {
-    "minLength": 1,
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 1024,
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / threadId / maxLength
```
Added value: +512
```

Changed13 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"
```

addedInput schema / properties / bodyFormat / anyOf

Added value: +[
+  {
+    "enum": [
+      "text",
+      "html",
+      "both",
+      "none"
+    ],
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

removedInput schema / properties / bodyFormat / enum

Removed value: -[
-  "text",
-  "html",
-  "both",
-  "none"
-]

removedInput schema / properties / bodyFormat / type
```
Removed value: -"string"
```

addedInput schema / properties / pageSize / anyOf

Added value: +[
+  {
+    "maximum": 25,
+    "minimum": 1,
+    "type": "integer"
+  },
+  {
+    "type": "null"
+  }
+]

removedInput schema / properties / pageSize / maximum
```
Removed value: -25
```
removedInput schema / properties / pageSize / minimum
```
Removed value: -1
```
removedInput schema / properties / pageSize / type
```
Removed value: -"integer"
```

addedInput schema / properties / pageToken / anyOf

Added value: +[
+  {
+    "minLength": 1,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

removedInput schema / properties / pageToken / minLength
```
Removed value: -1
```
removedInput schema / properties / pageToken / type
```
Removed value: -"string"
```

Changed1 schema field changedv0.11.1Oct 1, 2026
- removedOutput schema / $schema
```
Removed value: -"http://json-schema.org/draft-07/schema#"
```

Changed4 schema fields changedv0.11.0Sep 26, 2026

addedInput schema / properties / bodyFormat

Added value: +{
+  "enum": [
+    "text",
+    "html",
+    "both",
+    "none"
+  ],
+  "type": "string"
+}

addedInput schema / properties / pageSize

Added value: +{
+  "maximum": 25,
+  "minimum": 1,
+  "type": "integer"
+}

addedInput schema / properties / pageToken

Added value: +{
+  "minLength": 1,
+  "type": "string"
+}

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "data": {
+      "additionalProperties": false,
+      "properties": {
+        "id": {
+          "type": "string"
+        },
+        "messages": {
+          "items": {
+            "additionalProperties": true,
+            "properties": {
+              "accountId": {
+                "type": "string"
+              },
+              "attachments": {
+                "items": {
+                  "additionalProperties": true,
+                  "properties": {
+                    "filename": {
+                      "type": "string"
+                    },
+                    "id": {
+                      "type": "string"
+                    },
+                    "mimeType": {
+                      "type": "string"
+                    },
+                    "sizeBytes": {
+                      "type": "number"
+                    }
+                  },
+                  "required": [
+                    "id",
+                    "filename",
+                    "mimeType",
+                    "sizeBytes"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              },
+              "body": {
+                "additionalProperties": false,
+                "properties": {
+                  "html": {
+                    "type": "string"
+                  },
+                  "text": {
+                    "type": "string"
+                  }
+                },
+                "type": "object"
+              },
+              "bodyTruncation": {
+                "additionalProperties": {
+                  "additionalProperties": false,
+                  "properties": {
+                    "nextOffset": {
+                      "type": "number"
+                    },
+                    "totalChars": {
+                      "type": "number"
+                    }
+                  },
+                  "required": [
+                    "totalChars"
+                  ],
+                  "type": "object"
+                },
+                "type": "object"
+              },
+              "date": {
+                "type": "string"
+              },
+              "flags": {
+                "additionalProperties": true,
+                "properties": {
+                  "draft": {
+                    "type": "boolean"
+                  },
+                  "read": {
+                    "type": "boolean"
+                  },
+                  "starred": {
+                    "type": "boolean"
+                  }
+                },
+                "required": [
+                  "read",
+                  "starred",
+                  "draft"
+                ],
+                "type": "object"
+              },
+              "id": {
+                "type": "string"
+              },
+              "subject": {
+                "type": "string"
+              },
+              "threadId": {
+                "type": "string"
+              },
+              "to": {
+                "items": {
+                  "additionalProperties": true,
+                  "properties": {
+                    "email": {
+                      "type": "string"
+                    },
+                    "name": {
+                      "type": "string"
+                    }
+                  },
+                  "required": [
+                    "email"
+                  ],
+                  "type": "object"
+                },
+                "type": "array"
+              }
+            },
+            "required": [
+              "id",
+              "threadId",
+              "accountId",
+              "to",
+              "subject",
+              "date",
+              "flags"
+            ],
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "nextPageToken": {
+          "type": "string"
+        },
+        "subject": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "id",
+        "subject",
+        "messages"
+      ],
+      "type": "object"
+    }
+  },
+  "required": [
+    "data"
+  ],
+  "type": "object"
+}

First observedv0.1.0Jul 26, 2026

TDQS

C2.9/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context — that results are paged and capped at 50,000 body characters per page — but says nothing about how to continue paging, what happens at the end, or whether the cap truncates message bodies.

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 tight sentence with the resource and the paging constraint front-loaded; nothing is redundant. It is arguably over-terse, but every word present earns its place.

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

Completeness2/5

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

An output schema exists, so return values need no explanation, but this is a 5-parameter paginated read with 20% schema coverage and the description leaves pagination mechanics, bodyFormat choices, and pageSize limits entirely undocumented. For a paging tool, the absence of continuation guidance is a material gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 20% (only accountId is documented), so the description must compensate and largely fails. It never explains pageToken continuation, the pageSize maximum of 25, or the bodyFormat enum values (text/html/both/none); the 50,000-character statement is the only parameter-adjacent detail.

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 (read) and resource (messages in an email thread) and clarifies that results are paged. It is distinguishable from get_email/get_email_body by its thread-level, paged scope, though it never names 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 guidance on when to use this instead of get_email, get_email_body, or search_emails, nor any mention of prerequisites such as needing a threadId obtained elsewhere. Usage is only inferable from the word 'thread'.

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