Fluxmail

update_draft

Replace an existing draft's content completely, not just patch it. Overwrite body, subject, recipients, and attachments in a single operation.

Instructions

Replace the content of an existing draft (full replacement, not a patch).

Input Schema

TableJSON Schema

Name	Required	Description
`cc`	No	Recipients, each "Name <a@x.com>" or "a@x.com"
`to`	No	Recipients, each "Name <a@x.com>" or "a@x.com"
`bcc`	No	Recipients, each "Name <a@x.com>" or "a@x.com"
`from`	No	Connected address or an available send-as address
`draftId`	Yes
`subject`	No	Defaults to "Re: ..." when replying
`bodyHtml`	No	HTML body
`bodyText`	No	Plain-text body. Line breaks appear in the sent email. Keep each prose paragraph on one continuous line and separate paragraphs with blank lines.
`replyAll`	No	With replyToMessageId: reply to all original recipients
`accountId`	No	Account to operate on. Optional when exactly one account is connected.
`attachments`	No
`replyToMessageId`	No	Message being replied to; threads correctly and computes recipients if "to" is omitted

Output Schema

TableJSON Schema

Name	Required	Description	Default
`data`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

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

Changed2 schema fields changedv0.11.0Sep 26, 2026

changedInput schema / properties / bodyText / description

Previous value: -"Plain-text body"New value: +"Plain-text body. Line breaks appear in the sent email. Keep each prose paragraph on one continuous line and separate paragraphs with blank lines."

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "data": {
+      "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"
+    }
+  },
+  "required": [
+    "data"
+  ],
+  "type": "object"
+}

Changed1 schema field changedv0.9.0Sep 16, 2026

addedInput schema / properties / from

Added value: +{
+  "description": "Connected address or an available send-as address",
+  "format": "email",
+  "type": "string"
+}

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?

With no annotations, the description carries the full behavioral burden. It usefully discloses the destructive semantic that this overwrites content wholesale rather than merging — an important trait beyond the schema — but says nothing about whether unspecified fields are cleared, error behavior, or account/auth requirements.

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?

A single tight sentence with no waste and the key semantic front-loaded in parentheses. Appropriately sized, though it could have used one more sentence for usage context at little cost.

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?

An output schema exists so return values need no explanation, and the schema covers most parameters. However, for a 12-parameter mutation tool with zero annotations, the description leaves gaps around failure modes, field-clearing behavior, and when to prefer alternatives.

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 83%, so the schema already documents nearly all 12 parameters with formats and examples. The description adds no parameter-level detail; the 'full replacement' note only indirectly hints that all content fields must be re-supplied.

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 (replace) and resource (draft), and crisply distinguishes itself from a partial-update tool. It implicitly separates from siblings like create_draft and delete_draft, though it doesn't name them.

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 'full replacement, not a patch' clause gives useful preconditions for how to invoke it, but there is no explicit guidance on when to choose this over create_draft or a modify tool, nor any mention of required preconditions such as the draft already existing.

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