Mailrith Email Marketing

Create a broadcast

broadcasts_create

Creates a broadcast draft in the authenticated workspace. Effect: workspace-change. Retry with the same idempotency_key. Permission: broadcasts:write. API reference: https://mailrith.com/developers/api-reference.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "body": "<body>"
    },
    "name": "broadcasts_create"
  }
}

Input Schema

Name	Required	Description	Default
`body`	Yes	The exact JSON request body defined by the Mailrith public API contract.
`idempotency_key`	No	Optional idempotency key to retry the request safely. It must not exceed 256 UTF-8 bytes.

Output Schema

Name	Required	Description
`error`	No
`response`	No
`request_id`	Yes	The stable correlation ID for this MCP tool invocation.
`operation_id`	Yes	The stable Mailrith public API operation ID.

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedNov 2, 2026

changedInput schema / $defs / BroadcastUpsertRequest / properties / reply_to_email / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "description": "Empty or null uses the sender's current Reply-To. With a Mailrith sending domain, a value must be the workspace owner's verified account email or an address on that sender's domain, or the request fails with invalid_reply_to_email.",
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

changedOutput schema / $defs / Broadcast / properties / reply_to_email / anyOf

Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "description": "An override for this email's Reply-To. Null uses the sender's current Reply-To when the email is sent.",
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

Changed12 schema fields changedSep 3, 2026

changedInput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedInput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedInput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

removedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / $ref
```
Removed value: -"#/$defs/BroadcastEmailDocument"
```
addedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / allOf
```
Added value: +[
+  {
+    "$ref": "#/$defs/BroadcastEmailDocument"
+  }
+]
```

addedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

addedInput schema / $defs / BroadcastUpsertRequest / properties / subject / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedInput schema / properties / idempotency_key / description

Previous value: -"Optional idempotency key for safe retries."New value: +"Optional idempotency key to retry the request safely. It must not exceed 256 UTF-8 bytes."

addedInput schema / properties / idempotency_key / maxLength
```
Added value: +256
```

changedOutput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedOutput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

Changed12 schema fields changedSep 3, 2026

changedInput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes."

changedInput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello from Mailrith.",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedInput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello from Mailrith.",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

addedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / $ref
```
Added value: +"#/$defs/BroadcastEmailDocument"
```
removedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / allOf
```
Removed value: -[
-  {
-    "$ref": "#/$defs/BroadcastEmailDocument"
-  }
-]
```

removedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / description

Removed value: -"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

removedInput schema / $defs / BroadcastUpsertRequest / properties / subject / description

Removed value: -"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedInput schema / properties / idempotency_key / description

Previous value: -"Optional idempotency key to retry the request safely. It must not exceed 256 UTF-8 bytes."New value: +"Optional idempotency key for safe retries."

removedInput schema / properties / idempotency_key / maxLength
```
Removed value: -256
```

changedOutput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes."

changedOutput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello from Mailrith.",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedOutput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello from Mailrith.",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

Changed2 schema fields changedAug 21, 2026

changedInput schema / properties / idempotency_key / description

Previous value: -"Optional idempotency key for safe retries."New value: +"Optional idempotency key to retry the request safely. It must not exceed 256 UTF-8 bytes."

addedInput schema / properties / idempotency_key / maxLength
```
Added value: +256
```

Changed10 schema fields changedAug 17, 2026

changedInput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedInput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedInput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

removedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / $ref
```
Removed value: -"#/$defs/BroadcastEmailDocument"
```
addedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / allOf
```
Added value: +[
+  {
+    "$ref": "#/$defs/BroadcastEmailDocument"
+  }
+]
```

addedInput schema / $defs / BroadcastUpsertRequest / properties / body_document / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

addedInput schema / $defs / BroadcastUpsertRequest / properties / subject / description

Added value: +"For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / description

Previous value: -"A structured email document. The root node must use type `doc` and contain supported block nodes."New value: +"A structured email document. The root node must use type `doc` and contain supported block nodes. For Subscriber personalization in email subjects and body text nodes, use Mailrith bracket tokens such as [Subscriber_Name, fallback=\"friend\"] or [Subscriber_Email, fallback=\"\"]. Before using a custom field, call custom_fields_list or custom_fields_get and copy its personalization_token exactly. Do not use Handlebars-style variables such as {{ subscriber.name }}; Mailrith sends them as literal text."

changedOutput schema / $defs / BroadcastEmailDocument / example / content

Previous value: -[
-  {
-    "content": [
-      {
-        "text": "Hello from Mailrith.",
-        "type": "text"
-      }
-    ],
-    "type": "paragraph"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+        "type": "text"
+      }
+    ],
+    "type": "paragraph"
+  }
+]

changedOutput schema / $defs / BroadcastEmailDocument / examples

Previous value: -[
-  {
-    "content": [
-      {
-        "content": [
-          {
-            "text": "Hello from Mailrith.",
-            "type": "text"
-          }
-        ],
-        "type": "paragraph"
-      }
-    ],
-    "type": "doc"
-  }
-]New value: +[
+  {
+    "content": [
+      {
+        "content": [
+          {
+            "text": "Hello [Subscriber_Name, fallback=\"friend\"].",
+            "type": "text"
+          }
+        ],
+        "type": "paragraph"
+      }
+    ],
+    "type": "doc"
+  }
+]

First observedJul 30, 2026

TDQS

A4/5.0

Behavior4/5

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

Adds real context beyond annotations: the workspace-change effect, the required scope broadcasts:write, and safe-retry via idempotency_key. This complements the annotations (which only declare non-read-only, non-destructive, non-idempotent) and clarifies that idempotency is conditional on key reuse rather than a contradiction.

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?

Four short clauses, front-loaded with purpose, followed by effect, retry note, permission, and reference — every sentence carries distinct operational information with no redundancy.

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 mutation tool with a rich input schema and an output schema, the description covers effect, permission, and idempotency well. It stops slightly short on lifecycle framing (what a draft enables next), but nothing needed to call it correctly is missing.

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 coverage is 100% and the nested body_document/subject carry their own detailed personalization-token guidance, so the schema does the heavy lifting. The description only reiterates the idempotency_key semantics already documented in the schema property; baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

"Creates a broadcast draft in the authenticated workspace" gives a precise verb, resource, and state (draft — not send, not schedule), which cleanly separates it from siblings like broadcasts_send, broadcasts_schedule, and broadcasts_update without needing their schemas.

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 word "draft" implies this is the first step before send/schedule, but the description never names broadcasts_preflight, broadcasts_send, or broadcasts_update as follow-ups, nor does it state prerequisites (e.g. sender identity, audience). Usage is inferable but not routed.

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

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Create a broadcast

Tool call template

Input Schema

Output Schema

Schema Changelog

TDQS

Glama MCP Gateway

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